Journal of Biomedical Science

Summary Background Severe dengue reflects a temporally regulated interaction between viral burden, NS1 antigenaemia, cytokine and chemokine amplification, endothelial activation, glycocalyx injury, and organ stress. Although individual cytokines, endothelial markers, viral-burden measures, and clinical markers have been widely studied, the integrated pathogen-host evidence base remains fragmented. We synthesised evidence for cytokine, endothelial, and viral-burden signatures associated with severe dengue and assessed whether paired pathogen-host measurement provides a biologically coherent framework for severity assessment. Methods We searched MEDLINE, Embase, Scopus, Web of Science, Cochrane Library, Global Health, WHO Global Index Medicus, and medRxiv from database inception to 30 April 2026, without language restriction, for studies reporting viral burden, NS1 antigenaemia, cytokine, chemokine, endothelial, glycocalyx, inflammatory, or routine host-response markers in laboratory-confirmed dengue with severity outcomes. Eligible designs were prognostic-factor association studies, cross-sectional biomarker studies, and multivariable prediction-model studies. Risk of bias was assessed using QUIPS for prognostic-factor studies, PROBAST for prediction-model studies, and the relevant JBI critical appraisal checklist for cross-sectional biomarker studies, with the Newcastle-Ottawa Scale used selectively for cohort or case-control designs not amenable to QUIPS. Random-effects meta-analysis pooled standardised mean differences using restricted maximum likelihood with Hartung-Knapp adjustment. The protocol was registered with PROSPERO (CRD420261396923) before final extraction and synthesis. Findings Of 4,180 records identified, 79 studies including 47,612 participants met eligibility criteria. Forty-nine studies evaluated paired pathogen-host markers, 14 evaluated viral burden or NS1 antigenaemia alone, nine evaluated host biomarkers alone, and seven reported multivariable prediction models. Pathogen-side markers showed modest pooled severity associations whose magnitude depended on day of illness, immune status, and infecting serotype. Cytokine and chemokine markers, particularly IL-10, IL-6, IL-8, and CXCL10/IP-10, showed larger pooled effects favouring severe disease, while endothelial and glycocalyx markers, including angiopoietin-2 and syndecan-1, provided the most direct mechanistic link to plasma leakage. Routine clinical markers, especially platelet count, AST, ferritin, ALT, and lactate, retained substantial discriminatory value. Prediction models reported areas under the curve of up to 0{middle dot}96 in internal validation and 0{middle dot}97 in discovery analyses, but three had been externally validated, calibration was reported in two, and decision-curve analysis in none. Interpretation Current evidence supports severe dengue as an integrated pathogen-host injury syndrome in which viral burden and NS1 antigenaemia interact with cytokine amplification, endothelial dysfunction, glycocalyx injury, and routine markers of organ stress. The strongest translational direction is not a single biomarker but a parsimonious cytokine-endothelial-pathogen panel requiring prospective external validation across age groups, serotypes, immune-status strata, and endemic regions. Existing evidence supports candidate marker prioritisation and mechanistic synthesis, but not immediate routine clinical deployment.

Herpes Simplex virus type 1 (HSV-1) is a highly prevalent neurotropic virus from the alphaherpesviruses family. In recent years, a growing body of research has focused on the potential role of HSV-1 infections and recurrent reactivations in the pathophysiology of Alzheimers disease (AD). In particular, it has been hypothesized that HSV-1 could initiate or amplify the formation of neuropathological lesions characteristic of AD. To explore further this hypothesis, we adopted an integrated approach aiming at deciphering the impact of HSV-1 infection on AD molecular markers (A{beta} and Tau pathologies) and combining experimental animal models of in vivo infection, postmortem neuropathological analysis of AD brains, as well as in-vivo clinical analysis in AD patients. In animal models of peripheral (labial) infection with HSV-1 virus, we analyzed viral dissemination from peripheral tissues to the CNS, and the associated neuropathological consequences. Histological and molecular analyses revealed the occurrence of viral material (RNA, proteins) in the brainstem, the primary site of viral neuroinvasion, and in more anterior regions of the brain. Viral signatures were accompanied by early abnormal deposits of A{beta} peptides and accumulation of phosphoTau (pTau) proteins in various brain areas. Neuropathological examination of AD/control participants also underlined the presence of HSV-1 DNA in the human brainstem (pons) that was always associated with local A{beta}/Tau aggregates. Finally, in AD patients, associations were found between HSV-1 seropositivity and neuropathological lesion burden (region-specific Tau and A{beta} deposition detected by neuroimaging). Taken together, these data provide new evidence in favor of the involvement of HSV-1 in the pathophysiology of AD, stressing a possible causal link between HSV-1 infection, neuroinvasion and AD neuropathological hallmarks (A{beta} lesions and tauopathy).

Cyclooxygenase-1 (COX-1) is classically regarded as a constitutive enzyme that produces eicosanoids with housekeeping functions, but recent evidence indicates that it may also be involved in the acute phase of severe systemic inflammation. There is evidence indicating that COX-1 is selectively activated in the spleen via post-translational mechanisms early the course of LPS-induced systemic inflammation. However, the mechanistic link between COX-1 and the spleen has not yet been demonstrated in direct experiments. The present study was conducted to fill this gap. The effects of the COX-1 inhibitor SC-560 on the LPS-induced severity triad (hypotension, hypothermia and acidosis) were evaluated in rats subjected to splenectomy or in sham-operated controls. In the sham-operated group, SC-560 significantly attenuated the severity triad independently of changes in plasma cytokines (TNF and IL-1{beta}). In the splenectomized rats, SC-560 completely lost its ability to attenuate the hypotension and the acidosis induced by LPS. The effect of SC-560 on LPS-induced hypothermia was also impaired by splenectomy, though not completely. We then conducted a lipidomic screening to identify which COX-1-derived eicosanoids might be responsible for mediating the severity triad. Based on spleen-blood correlations, the screening identified PGE2 and PGD2 as putative candidates. In conclusion, the present study provides direct evidence for a mechanistic link between the spleen and COX-1 in the mediation of severity in systemic inflammation, and identifies PGE2 and PGD2 as putative candidates involved.

Background: Vascular contributions to cognitive impairment and dementia (VCID) are thought to arise from distributed neurovascular unit (NVU) dysfunction rather than focal pathology, yet the transcriptional architecture of human VCID brain tissue and the status of endogenous counter-regulatory signaling within it remain incompletely characterized. Defining whether protective pathways are engaged and why they may be insufficient is critical for identifying therapeutic entry points in a disease lacking approved treatments. Methods: We performed differential gene expression analysis (DESeq2 v1.38.0) and pre-ranked gene set enrichment analysis (fgsea v1.24.0) on bulk RNA-sequencing data from superior parietal lobe tissue (GEO:GSE303449; n = 40; 19 VCID, 21 controls; model: age_scaled + Sex + condition), followed by Spearman correlation analysis, PI3K-Akt pathway level, leading-edge decomposition, and single-nucleus RNA-seq endothelial cell characterization (GEO:GSE282111). Results: No individual gene reached FDR < 0.05 for differential expression between VCID and control across 51,962 genes tested. Gene set enrichment analysis nonetheless identified eight significantly enriched pathway programs (all FDR < 0.05) that were upregulated, encompassing inflammatory, stress-response, cytoskeletal, and apoptotic signaling, consistent with distributed network-level dysregulation rather than dominant single-gene effects. The MAS1/ANG1-7 associated signaling gene set (54 genes) was the only counter-regulatory pathway achieving significance (NES = 1.381, FDR = 0.0127). MAS1 receptor expression was strongly (absolute Spearman's rho >= 0.64) and inversely associated with NF-kB pathway drivers TLR4 (Spearman's rho = -0.804) and IKBKB (Spearman's rho = -0.797; both FDR = 4.73 x 10^-9). Further, 9 of 12 correlations between MAS1 downstream effectors and endothelial activation markers were FDR-significant and positive, indicating that the downstream protective effector program is co-activated by inflammatory stress rather than directed by its receptor. Single-nucleus RNA-seq supports endothelial enrichment of the MAS1 pathway enrichment signal in VCID brain tissue. PI3K-Akt leading-edge decomposition revealed 96% gene-level non-overlap between inflammatory and vasoprotective arms. Conclusions: Human VCID brain tissue exhibits coordinated pathway-level dysregulation in the absence of dominant individual-gene effects, consistent with a disease driven by distributed transcriptional network stress. The MAS1/ANG1-7 vasoprotective axis is transcriptionally engaged and endothelially enriched, yet receptor expression is inversely associated with inflammatory signaling while downstream effectors remain transcriptionally engaged. This pattern suggests a failed compensatory state in the VCID superior parietal lobe. This architecture is consistent with a transcriptionally primed but receptor-constrained protective program. These findings suggest that therapeutic strategies restoring MAS1 receptor-level input to an already engaged downstream program may represent a plausible therapeutic strategy for VCID, pending experimental validation.

Abstract Background: The Chikungunya virus (CHIKV), a re-emerging mosquito-borne alphavirus, is responsible for acute febrile illness and severe polyarthralgia. Although both innate and adaptive immune responses influence the disease outcomes, the detailed cellular immunopathogenesis of CHIKV in peripheral blood is not yet fully elucidated. Methods: We conducted single-cell RNA sequencing (scRNA-seq) on peripheral blood mononuclear cells (PBMCs) obtained from patients acutely infected with CHIKV and from healthy control subjects. Cellular interactions were inferred, and the transcriptomic results were orthogonally validated through quantitative real-time PCR (qPCR) and Enzyme-Linked Immunosorbent Assay (ELISA) to assess systemic interferon-stimulated responses. Furthermore, a comparative analysis was performed using publicly available single-cell data from Dengue virus (DENV) infections. Results: CHIKV infection significantly altered the immune system, increasing monocytes and dendritic cells while reducing T and B lymphocytes. Monocytes and NK cells showed strong activation of interferon-stimulated genes (ISGs). Monocytes were identified as key in driving inflammatory and immune responses. In adaptive immunity, CHIKV led B cells to become plasmablasts with antiviral immunoglobulins and caused T cells and NK-like T cells to show signs of cytotoxicity and exhaustion. Validation showed increased levels of IFN-{gamma}, IFN-{beta}1, MX1, and ISG15. CHIKV triggered a more intense, monocyte-driven interferon response than DENV. Conclusions: Acute CHIKV infection induces a systemic interferon response predominantly centered on monocytes, accompanied by significant alterations in adaptive immunity. Circulating ISG products, including MX1 and ISG15, reflect the transcriptomic activation and may serve as potential biomarkers for assessing the early intensity of innate antiviral responses.

The APOE gene is a critical determinant of human healthspan and longevity, with the rare{varepsilon} 2 allele traditionally viewed as a universal protective factor against Alzheimer s disease (AD) and a driver of exceptional lifespan. However, this protective paradigm is predominantly derived from European-centric cohorts, leaving the evolutionary and clinical impacts of{varepsilon} 2 across diverse, highly admixed populations largely unknown due to a lack of local ancestry (LA) resolution. To investigate how local genomic backgrounds modulate APOE survival dynamics we analyzed two Brazilian sample collection of older adults from Sao Paulo city: the Biobank for Aging Studies (BAS, n = 716), a post-mortem autopsy study of naturally deceased individuals; and the Health, Well-being and Aging Study (SABE, n = 952), a census-based elderly sample collection. We evaluated deviations from Hardy-Weinberg equilibrium (HWE) using robust permutation-based models to capture ongoing selective and mortality pressures at the APOE locus. While global APOE frequencies adhered to HWE, integrating LA unveiled striking, mirrored ancestral deviations. Our findings reveal that APOE {varepsilon}2 homozygotes with African ancestry significantly contribute to deviations from HWE in the BAS, with an excess of {varepsilon}2AFR/{varepsilon}2AFR homozygotes observed (p = 0.0196). These distinct HWE deviations demonstrate that an African LA background acts as a genetic buffer, attenuating the phenotypic extreme effects of APOE alleles. Furthermore, we observed an excess of the{varepsilon} 4 European haplotypes in the BAS, which is consistent with a mortality pressure allelic effect in the European LA context. Conversely, the{varepsilon} 4AFR/{varepsilon}4AFR combination was overrepresented in the SABE. While this buffering mechanism mitigates{varepsilon} 4 toxicity, it simultaneously dampens the exceptional longevity advantage typically conferred by the{varepsilon} 2 allele, leading to its neutral accumulation in the post-mortem cohort. Our study challenges the "one-size-fits-all" assumption of APOE biomarkers, demonstrating that{varepsilon} 2 protective mechanisms are context-dependent and modulated by local genomic backgrounds in admixed populations.

Background: Parkinson's disease (PD) is the second most common progressive neurological disorder that is pathologically characterized by the loss of dopaminergic neurons within the substantia nigra (SN). However, disease progression probably involves coordinated changes across both neuronal and glial cell populations. Although single-nucleus RNA-seq resolved cell-type-specific transcriptional profiling, differential expression and regulatory interpretation are commonly reported separately; however, they may limit the mechanistic prioritization to uncover novel therapeutic targets. Methods: Here, we performed sample-aware pseudobulk framework analysis on single-nucleus transcriptomes obtained SN of PD and control donors. Cell-type-specific differential expression for PD vs. control was identified using edgeR quasi-likelihood modeling (FDR < 0.05; |log2FC| > 0.5). Further, to quantify disease-specific remodelling, we computed one-vs-rest cell-type specificity scores in each condition and defined delta-specificity as the PD-control shift. We further prioritized the gene-set for dopaminergic neurons and microglia based on edge R significance and delta-specificity shifts, followed by upstream regulatory assessment using transcription factor enrichment and subnetwork visualization using ChEA-KG. Moreover, we used Cellchat to identify altered cell-cell communication networks to infer differences between both conditions. Results: Dopaminergic neurons demonstrated upregulation of neuronal-state remodeling transcriptional programs related gene sets in PD group, including receptor signaling and contact/guidance pathways (e.g., CHRM3, ROBO1, PLXNA4, UNC5D, EFNA5), neuronal excitability homeostatsis, RNA components, cellular traffickings and proteostasis, suggesting coordinated remodeling in surviving neuronal population. Microglia exhibited a compact PD-associated signature enriched for regulatory and activation state-related genes. TF networks analysis revealed distinct regulatory subnetwork in each population,including BNC2-centered network in microglia and an NPAS3-centered network in dopaminergic neurons with embedded ZNF804A and chromatin-associated components. Conclusions: In summary, integrating pseudobulk, delta-specificity scoring and TF-network enrichment analysis provides coherent dopaminergic and microglial programs in PD substantia nigra. This framework prioritizes cell-type-specific potential candidate mechanisms for downstream validation. The inferred regulatory networks and interactions are hypothesis generating and need orthogonal validation, such as spatial or proteomics approaches and independent cohorts.

HIV-associated neurocognitive disorders (HAND) have become a major clinical concern, particularly among the aging HIV-1-seropositive population, which is generally characterized by persistent viral reservoirs and a lower level of chronic inflammation. NLRP3 inflammasome activation exhibits its unique role in the progression of many chronic inflammatory diseases. Furthermore, pyroptosis, an inflammatory form of programmed cell death, has been implicated in numerous neurological diseases. However, the mechanisms linking EcoHIV infection, microglial pyroptosis, and NLRP3 inflammasome activation remain incompletely understood. In this study, EcoHIV was retro-orbitally injected into C57BL/6J wild-type mice and analyzed at 14-, 30-, 60-, and 90-days post-infection to establish a NeuroHIV model. Additionally, in vitro, BV2 microglial cell line was infected with EcoHIV and treated with MCC950, an inhibitor of the NLRP3 inflammasome, for three days. Pyroptosis marker GSDMD, NLRP3 inflammasome components, Caspase-1 (a marker of inflammasome activation), HLA-DR (an immune activation marker), Programmed-death 1 (PD-1, an immune checkpoint molecule), and Ki67 (a cellular proliferation marker) were assessed by immunofluorescence staining. Results showed that EcoHIV-infected mice showed a peak in NLRP3 expression at 14 days post-infection, compared with controls, followed by a modest decline at 30 days, while GSDMD expression increased progressively across 14 and 30 days. These findings demonstrate dynamic changes in microglial pyroptosis and NLRP3 inflammasome activation over the course of EcoHIV infection. In vitro, EcoHIV-infected BV2 cells exhibited significantly increased EcoHIV-eGFP fluorescence compared with controls, confirming the utility of BV2 cells as an in vitro model of microglial EcoHIV infection. Expression levels of GSDMD and NLRP3 were elevated following infection, indicating enhanced pyroptosis and neuroinflammation. Treatment with MCC950 significantly reduced the expression of GSDMD, NLRP3, HLA-DR, PD-1, and Ki67, suggesting that inhibition of NLRP3 inflammasome activity suppresses both pyroptosis and microglial activation and proliferation. Together, elucidating the interplay between microglial pyroptosis and NLRP3 inflammasome activation may provide new insights into the pathogenesis and potential therapeutic strategies for NeuroHIV in the aging HIV-1-seropositive population.

IntroductionReduced or absent capillary blood flow (termed no-reflow) even after arterial recanalization is associated with poorer neurological outcomes following ischemic stroke. The aim of the current study was to test whether acute administration of peptidylglycine -amidating monooxygenase (PAM) can increase capillary blood flow and improve brain recovery after ischemic stroke. MethodsA 60-minute ischemic stroke was induced using middle cerebral artery occlusion (MCAO) in rats. A modified, long-acting PAM enzyme was administered 30 minutes after induction of ischemia and rats were recovered for either 24 hours or 7 days. In all animals, real-time cerebral blood flow was assessed before, during and after MCAO using trasncranial contrast enhanced ultrasound (tCEU). For rats in the 7-day protocol, a modified neuroscore test was used to assess neurological deficit following MCAO. At the end of each experiment, a transcardiac perfusion was used to generate a fluorescent vascular cast and histology was used to examine capillary diameters and determine infarct volume. ResultsFollowing MCAO and arterial recanalization, untreated rats had reduced cerebral blood flow across brain regions affected by ischemia, indicative of no-reflow. PAM administration led to enhanced cerebral blood flow in affected regions, and this was associated with increased capillary diameters 24 hours after ischemic stroke. Although there was no difference in infarct volume at 24 hours, by day 7, infarct volume was markedly reduced in the PAM group and these animals exhibited improved neurological function compared to the untreated group. ConclusionAdministration of PAM improves capillary blood flow after ischemic stroke leading to enhanced neurological and brain recovery. This work highlights PAM as a novel theraputic approach to improve brain blood flow and recovery after ischemic stroke. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/732201v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@1637bdeorg.highwire.dtl.DTLVardef@59548aorg.highwire.dtl.DTLVardef@bd365borg.highwire.dtl.DTLVardef@3baf84_HPS_FORMAT_FIGEXP M_FIG C_FIG

BackgroundMicroglial heterogeneity is a fundamental feature of brain homeostasis and pathology. The purpose of this study was to investigate the complexity of microglial plasticity by characterizing specialized oligodendrocyte-like microglial subsets. MethodsThe study was performed utilizing single-cell transcriptomics analyses and immunofluorescence staining to identify and profile microglial subpopulations. Additionally, spatial transferring and morphological analyses were conducted to determine the anatomical distribution and structural features of these specific cells. ResultsWe identified a distinct microglial subset termed dual-phenotype microglia (DPM), which co-expresses microglial and oligodendrocyte markers. DPM consisted of two subtypes with distinct functions: myelin-associated DPM (mDPM) and neuron-associated DPM (nDPM). Spatial and morphological evaluations revealed that mDPMs were sparsely distributed across the whole brain and exhibited a highly ramified architecture, whereas nDPMs were enriched in the hippocampal dentate gyrus. Mechanistically, we found that mDPM function was driven by the Sox10 regulon to modulate myelin maintenance and axonal ensheathment, while nDPM was orchestrated by Glis2, facilitating essential neuron-glia crosstalk and synaptic regulation. Furthermore, we demonstrated that nDPM and mDPM were predicted to undergo significant alterations in multiple sclerosis and Alzheimers disease. Notably, mDPMs were selectively enriched in active multiple sclerosis lesions, revealing that DPM were closely related to neuropsychiatric disorders. ConclusionsBy comprehensively characterizing the morphology, molecular signatures, and spatial logic of these oligodendrocyte-like microglial subsets, our study elucidated the complexity of microglial plasticity. These findings provided new insights into their diverse roles in central nervous system health and disease. Graphical abstractIdentification, Molecular Profiling, and Functional Modeling of Dual-Phenotype Microglia (DPM). (1) Discovery: Identification of the dual-phenotype microglia (DPM) population through single-cell transcriptomics. (2) Molecular Signatures: The transcriptomic identity of DPM subtypes is governed by specific regulatory networks. (3) Distribution & Pathology: Spatial mapping reveals divergent anatomical logic and disease relations for DPM subtypes. (4) Mechanism/Theory: A proposed functional model of mDPMs as "metabolic relay" and support units. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/724239v2_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@b7db1dorg.highwire.dtl.DTLVardef@9265e7org.highwire.dtl.DTLVardef@1605d82org.highwire.dtl.DTLVardef@19b048f_HPS_FORMAT_FIGEXP M_FIG C_FIG

The blood-brain barrier (BBB) plays a central role in brain function and is increasingly implicated in neurodegenerative disease. Major neurodegenerative disorders, including Alzheimer's disease (AD), frontotemporal dementia (FTD), and Huntington's disease (HD), share overlapping pathological features. Yet, the extent to which these diseases converge or diverge at the level of BBB-associated cell types remains poorly understood. Here, we performed a comparative analysis of vessel-enriched human brain transcriptomic datasets across AD, FTD, and HD to define shared and disease-specific neurovascular alterations. We identify a partially conserved transcriptional signature of vascular dysfunction across all three diseases, alongside disease-specific changes in endothelial, pericyte, and perivascular cell populations. Endothelial remodeling was most prominent in capillary and venous segments, highlighting segment-specific vulnerability along the arteriovenous axis. Notably, we identified two molecularly distinct human pericyte subtypes across all three datasets and found a consistent reduction in the matrix-type pericytes (M-peri) fraction, suggesting a selective decline. Cell-cell communication analysis further revealed reorganized endothelial-pericyte signaling networks, with prominent alterations in extracellular matrix-associated pathways, including LAMININ, COLLAGEN, FN1, and NCAM, together with changes in contact-dependent and vascular signaling pathways such as NOTCH and VEGF. Together, our findings define shared and disease-specific neurovascular mechanisms across major neurodegenerative disorders and highlight BBB-associated pathways as central features of neurodegeneration, providing a framework for future diagnostic and therapeutic strategies.

Blood-brain barrier (BBB) breakdown is a critical pathological event driving secondary brain injury and poor outcomes following intracerebral hemorrhage (ICH). However, the mechanisms governing acute BBB breakdown after ICH remain incompletely understood. Here we demonstrate that the Sphk1-S1P-S1PR3 signaling plays a pivotal role in this process. Sphk1 expression was significantly upregulated in the perihematomal endothelial cells of both ICH patients and mice, with levels positively correlating with BBB dysfunction severity and poor clinical outcomes. Using endothelial-specific genetic gain- and loss-of-function approaches, we found that Sphk1 knockdown attenuated BBB leakage, reduced hematoma volume and brain edema, preserved tight junction integrity, and improved neurological function at 1-day post-ICH, whereas Sphk1 overexpression exacerbated these pathological features. Mechanistically, transcriptomic profiling of perihematomal endothelial cells revealed that prior to its established role in Nlrp3-mediated pyroptosis, Sphk1 promotes early BBB breakdown by regulating the Bsg-MMP-9 axis. Endothelial-specific Bsg deletion completely abrogated the deleterious effects of Sphk1, confirming Bsg as an indispensable intermediary through which Sphk1 signals to MMP-9. ATAC-seq and dual-luciferase assays further demonstrated that Sphk1-generated S1P signals through S1PR3 to activate HIF-1, which directly binds the Bsg promoter to drive its transcription, ultimately promoting MMP-9-mediated tight junction degradation. These findings delineate a complete hierarchical signaling cascade from metabolic enzyme to transcriptional regulation and subsequent barrier injury, establishing the Sphk1-Bsg-MMP-9 axis as a promising therapeutic target for ICH. One sentence summaryThis work identifies an early and pivotal mechanism of blood-brain barrier breakdown after intracerebral hemorrhage, demonstrating that Sphk1-generated S1P signals through S1PR3 to activate HIF-1, which directly transactivates Bsg expression, leading to MMP-9-mediated tight junction degradation, thereby establishing a novel hierarchical axis with therapeutic potential.

ObjectiveLong-term sequelae following viral infections, such as Chikungunya and SARS-CoV-2, are associated with persistent symptoms, with a notably higher prevalence in women. This study investigated the early determinants of progression to chronic chikungunya (CC) and examined the specific role of biological sex on disease outcomes. MethodsWe analysed peripheral blood mononuclear cells (PBMCs) sampled within seven days of disease onset, recruited between 2016 and 2020. The study compared patients who eventually recovered (RC, n = 11) with those who progressed to develop CC (n = 24). We analysed gene signatures through transcriptomics and validated the results using qRT-PCR and flow cytometry ResultsTen genes were differentially expressed between the cohorts. Specifically, the study identified an upregulation of IKZF2 (encoding Helios) in CC patients, which was confirmed by qRT-PCR. Conversely, ACKR3 (encoding a CXCL12 scavenger in the ACKR3/CXCR4/CXCL12 axis) was upregulated in RC patients and validated by flow cytometry. Furthermore, CC cases demonstrated higher viral loads and downregulation of IFN- and IFN-{gamma} pathways. We also found that immune profiles differed between men and women; specifically, interferon /{gamma} and TNF signalling pathways were upregulated in women with CC but downregulated in men with CC relative to recovered individuals. DiscussionImmune profiles differed significantly between men and women within both the CC and RC groups. These findings suggest that progression to chronic disease is influenced by an impaired early antiviral response combined with sex-specific immune regulation. Furthermore, ACKR3 and IKZF2 are identified as potential prognostic biomarkers for chronic chikungunya.

Familial Amyotrophic Lateral Sclerosis (fALS) is a fatal neurodegenerative disease, mainly caused by mutations in the superoxide dismutase 1 (SOD1) protein. Mitochondrial dysfunction is a primary hallmark of ALS pathogenesis. However, the molecular mechanism by which SOD1 mutants impair organellar health remains enigmatic. This study demonstrates that mutant SOD1 associates with the TIM23 complex in Saccharomyces cerevisiae via its intermembrane space (IMS) domain. In ALS-associated SOD1 mutants, both binding and expression of TIM23 complex proteins were downregulated, leading to altered translocation of the substrate protein Sdh3, a component of the electron transport chain (ETC) complex II. Disrupted Sdh3 translocation leads to mitochondrial dysfunction, evidenced by decreased ETC complex II activity, reduced functional mass, and compromised organelle integrity. Overexpression of Tim23 partially rescued mitochondrial integrity by increasing ETC complex activity and functional mass and restoring reticular morphology. Strikingly, the improved mitochondrial homeostasis in Tim23-overexpressing cells partially rescued the growth defects caused by mutant SOD1. Collectively, these findings reveal a previously unrecognized regulatory axis between mutant SOD1 and the mitochondrial pre-sequence translocase machinery, highlighting this pathway as a promising target for future ALS therapies and opening new avenues for mechanistic and translational research. Author SummaryFamilial Amyotrophic Lateral Sclerosis (fALS) is a progressive, fatal neuromuscular disorder marked by motor neuron degeneration. The exact cause of ALS remains unclear. Previous research links familial ALS to mutations in the superoxide dismutase 1 (SOD1) gene. SOD1 mutants in ALS disrupt mitochondrial protein translocation, a key mitochondrial process. The mechanism by which SOD1 mutants affect mitochondrial function and integrity by modulating presequence translocase (TIM23 complex) import is not yet understood. The current study addresses a critical gap in ALS research by demonstrating a novel, direct interaction between SOD1 and Tim23 that regulates mitochondrial function in yeast. We found that SOD1 binds Tim23 via Tim23 IMS domain, stabilizes the Tim23CORE complex, enabling Sdh3 import. Loss of SOD1, Tim23, or Tim50 destabilizes the TIM23CORE complex, leading to impaired Sdh3 import and decreased ETC complex-II activity. These changes disrupt mitochondrial structure, causing fragmentation and a loss of functional mitochondrial mass in {Delta}sod1. ALS-linked SOD1 mutants show similar effects: they diminish Sdh3 import by weakening SOD1-Tim23 interaction and lowering TIM23 complex stability, resulting in punctate mitochondria and reduced mitochondrial mass. Collectively, our study identifies the SOD1-TIM23 interaction as a key regulator of mitochondrial health through Sdh3 import via the TIM23CORE complex and indicates this pathway as a potential early intervention target for ALS therapy.

Efficient cerebrovasculature is vital to neuronal health and cognition and evidence shows most dementia patients have cerebrovascular abnormalities. Brain vasculature is regulated by Vascular Endothelial Growth Factors (VEGFs) binding VEGF receptor2 (VEGFR2) and stimulating angiogenesis, and neuroprotection. Presenilin1 (PS1) is the main proteolytic component of {gamma}-secretase and PS1 mutants are the most common cause of Familial Alzheimer Disease (FAD). Here we show that an ADAM17 cleavage of extracellular VEGFR2 produces the membrane-bound {gamma}-secretase substrate VEGFR2/CTF1 (called VCTF1), comprising the transmembrane and intracellular domains of VEGFR2. PS1 FAD mutants and {gamma}-secretase inhibitors both accumulate VCTF1 and suppress VEGF-A-induced brain angiogenesis. Moreover, PS1 FAD mutants, {gamma}-secretase inhibitors, and PS1 downregulation, all decrease {gamma} secretase processing of VCTF1, thereby increasing its accumulation and impairing VEGF-A-induced VEGFR2 dimerization/activation, signaling, and endothelial cell (EC) functions. Importantly, VCTF1 binds fulllength VEGFR2 monomers suppressing VEGFR2 dimerization/activation, signaling, and EC functions. These data show that VCTF1 suppresses VEGFR2 dimerization and downstream signaling and functions of the brain VEGF-A-/VEGFR2 system. PS1 FAD mutants increase vulnerability of brain neurons to ischemic stress and exert antimorphic effects on {gamma}-secretase cleavage of VCTF1, increasing its concentration and abolishing VEGF-A-induced VEGFR2 dimerization/activation, signaling, neuroprotection and cognition. Importantly, we detected molecular markers of decreased VEGFR2 dimerization and angiogenic dysfunction in human brain tissue from PS1 FAD mutant genotypes. Together, our data suggest a pathway through which FAD mutants promote dementia by increasing VCTF1 and decreasing brain angiogenesis and neuroprotection, suggesting that PS1 FAD patients may benefit from therapeutic methods that decrease brain VCTF1.

Background: Age is the most important risk factor for coronary artery disease (CAD) independent of traditional risk factors. Aging induces classic pro-inflammatory and prothrombotic vascular phenotypic changes whose molecular mediators remain poorly understood. Medin is a common cleavage product protein that accumulates in vasculature with aging and shown to cause endothelial dysfunction. Its role in CAD is unknown. The study aimed to evaluate the effects of medin on human coronary artery endothelial cell (HCAEC) pro-inflammatory and prothrombotic activation and establish the relationship between medin and coronary atherosclerosis in human decedents. Methods: HCAECs were exposed to physiologic dose of medin (5 M) for 20 hours and ribonucleic acid sequencing (RNAseq) with signaling pathway analyses and reverse transcription polymerase chain reaction of select pro-inflammatory and prothrombotic genes performed. Corresponding protein expression was measured by Western blot or enzyme linked immunosorbent assay in HCAECs exposed to medin (5 M) without or with nuclear factor-{kappa}B (NF{kappa}B) inhibitor RO106-9920 (10 M). Coronary arteries from 40 deceased individuals underwent immunohistochemistry and medin and plaque burden were quantified and their relationship evaluated. Results: RNAseq showed predominant pro-inflammatory gene expression changes induced by medin. HCAECs treated with medin showed increased phosphorylated NF{kappa}B, elevated protein expression of interleukin (IL)-6, IL-8, monocyte chemotactic protein (MCP)-1, intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1 and plasminogen activator inhibitor (PAI)-1 and reduced protein expression of thrombomodulin; these changes were reversed by RO106-9920 co-treatment. In human tissues, coronary artery medin strongly correlated with plaque burden (R=0.76, p<0.0001) and coronary macrophage content (R=0.72, p<0.0001). Coronary arteries from decedents with myocardial infarction had higher medin than those without (5.53{+/-}2.67% versus 0.02{+/-}0.02%, p=0.0005). Conclusions: Medin induced NF{kappa}B-mediated endothelial cell pro-inflammatory and prothrombotic activation and was strongly associated with coronary plaque burden and inflammation. Medin is a novel candidate mediator linking aging and coronary atherosclerosis.

Chaperonins complex into double-ringed octamers to aid peptide folding. Recent evidence implicates dysfunctional chaperonin subunits in cancer and neurodegenerative diseases because their deregulation exacerbates cellular injury. Nevertheless, a gap of knowledge exists regarding the expression and localization of chaperonin subunits in relation to amyloidogenic processes in Alzheimers disease (AD). Here, we show that reduced levels of chaperonin-containing TCP-1 subunits 2 (CCT2) and 3 (CCT3) stratify AD, with the subcellular distribution of their residua being mutually exclusive with both {beta}-amyloid and hyperphosphorylated tau in neurons. We find CCT3 localized to a subset of glial fibrillary acidic protein-positive astrocytes in AD. Increased oxidative stress in vitro upregulated CCT3 expression in astrocyte-like U251 cells. Conversely, CCT3, but not CCT2, loss-of-function in neuron-like SH-SY5Y cells increased intracellular {beta}-amyloid load. These data suggest that CCT2/CCT3 are faithful disease-state indicators and implicate CCT3 in oxidative stress-dependent cellular damage pathways.

Defects in lysosomal lipid handling provoke fatal disorders presenting neurovisceral symptoms with variable onset and life spans. A prime example is Niemann-Pick type C disease (NPCD), where export of cholesterol and other lipids from the endosomal-lysosomal system is impaired due to variants of either NPC intracellular cholesterol transporter 1 (NPC1) or NPC intracellular cholesterol transporter 2 (NPC2). Therapeutic options for NPCD are limited to palliative care and disease-modifying drugs, and there is an unmet need for new treatments. Based on positive effects in patient-derived fibroblasts in vitro, we explored how inhibition of bromodomain and extra-terminal domain (BET) proteins affects a well-established mouse model bearing the frequent I1061T variant of NPC1. Treatment with JQ1, a hydrophobic prototype BET protein inhibitor, induced beneficial but sex-dependent molecular and behavioral changes in mice. Our results indicate bromodomain proteins as therapeutic drug target for NPCD and reveal sex-dependent BET protein signaling in mice.

Overexpression of -synuclein (-syn), an inherently disordered protein, triggers chronic activation of the mitochondrial unfolded protein response (UPRmt) pathway in Caenorhabditis elegans with enhanced dopaminergic (DAergic) neurodegeneration. Introduction of a loss-of-function(lf) mutation in atfs-1, the main transcriptional regulator of the UPRmt, into -syn nematodes results in significant neuroprotection from -syn-induced DA neuron loss, indicating that compensatory mechanisms provide neuroprotection. We performed a F3 forward genetic screen in C. elegans atfs-1(lf) mutants to identify molecular components associated with the modulation of neurodegeneration via UPRmt signaling in -syn-expressing DA neurons. Homozygous mutant animals were examined for enhanced neurodegeneration; multiple independent alleles were uncovered. Among these, we identified new nonsense alleles encoding the histone lysine demethylases (H3K27me3), jmjd-1.2 and jmjd-3.1. Another line carried a nonsense allele of twk-14. This gene encodes a conserved protein termed KCNK12 in mammals that facilitates passive background K+ leak currents to set and stabilize resting membrane potential. To further examine the association of these gene products in DA neurodegeneration, mutants and/or RNA interference were employed. DA neurodegeneration was observed in the -syn + atfs-1(lf) background when jmjd-1.2, jmjd-3.1, or twk-14 were individually depleted. These results provide evidence that jmjd-1.2 and jmjd-3.1, which encode previously characterized H3K27me3 demethylases, and the uncharacterized twk-14 gene product, orthologous to human KCNK12, naturally confer protection from -syn neurotoxicity.

ObjectivesPrior studies have shown that cyclin D1 regulates diverse aspects of liver metabolism during cell cycle progression. Interestingly, this protein is induced in hepatocytes by feeding, but its function in modulating hepatic postprandial physiology is poorly characterized. The aim of this study was to evaluate the contribution of cyclin D1 to the hepatic response to feeding and to gain insight into its potential non-proliferative roles in other conditions. MethodsMice with or without hepatocyte cyclin D1 (D1fl/fl or D1{Delta}Hep) were fasted and refed a high-carbohydrate diet. Mouse and human liver in the setting of aging and MASLD were analyzed. The C. elegans model was used to evaluate the role of cyclin D1 (CYD-1) in response to overnutrition. ResultsCyclin D1 regulated hepatic gene networks involved in glucose and lipid metabolism, protein synthesis, immune response, and other pathways after feeding. Induction of acute phase response proteins was markedly inhibited in D1{Delta}Hep mice, which was associated with corresponding changes in histone acetylation on key genes. In aged liver, hepatocyte cyclin D1 was induced without associated proliferation; this was markedly pronounced in progeroid Ercc1-deficient mice. Cyclin D1 was upregulated in MASLD and diminished with successful treatment. CYD-1 was induced by overnutrition in the intestine of Caenorhabditis elegans (which performs metabolic functions similar to liver) and regulates key nutrient-responsive proteins. CYD-1 inhibition prolonged lifespan in this setting. ConclusionsCyclin D1 regulates nutrient-mediated physiology in the liver and C. elegans, indicating that it has unexpected and highly conserved metabolic functions. Further study is warranted to define its role in hepatic disease and aging. HighlightsO_LICyclin D1 is induced in hepatocytes with feeding and broadly regulates hepatic gene expression. C_LIO_LIAcute phase response (APR) and senescence-associated secretory phenotype (SASP) proteins are markedly regulated by cyclin D1. C_LIO_LIHepatocyte expression of cyclin D1 is substantially upregulated in aging, premature aging, and MASLD without associated proliferation. C_LIO_LICyclin D1 (CYD-1) regulates nutrient-mediated signaling and lifespan in response to overnutrition in C. elegans. C_LI