Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease

Wolfram syndrome is a rare autosomal recessive disorder characterized by antibody-negative early-onset diabetes mellitus, optic atrophy, sensorineural hearing loss, arginine-vasopressin deficiency, and progressive neurodegeneration of the brainstem and cerebellum. It is caused primarily by pathogenic variants in the WFS1 gene, which encodes a transmembrane endoplasmic reticulum-resident protein involved in the unfolded protein response and cellular calcium homeostasis. Although multiple rodent models of Wolfram syndrome have been developed and shown to exhibit visual defects, some studies have reported significant vision loss prior to any detectable axonal degeneration or myelin abnormalities, and the mechanisms underlying these early visual deficits remain poorly understood. Recent in vitro studies have demonstrated altered synaptic contacts and aberrant neurite morphology in WFS1-deficient cerebral organoids and human iPSC-derived neurons, respectively. These findings prompted us to investigate, for the first time in vivo, whether synaptic and dendritic abnormalities occur in the retina of Wfs1 knockout mice. Using confocal microscopy, we examined retinal and optic nerve histology in Wfs1 knockout mice at 4 and 7 months of age. Our analysis reveals progressive synaptic alterations in the inner plexiform layer, driven by early presynaptic compartment failure. These changes represent the earliest detectable phenotype associated with vision loss in this model and precede overt axonal degeneration.

Metabolic syndrome (MetS), characterized by abdominal obesity, insulin resistance, dyslipidemia, and hypertension, affects a substantial proportion of the global population and increases the risk for cardiovascular disease, diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD). Despite its prevalence, there are currently no effective pharmacological therapies targeting MetS, highlighting the need to identify novel etiological mechanisms, particularly within the gastrointestinal (GI) tract. Using a mouse model of MetS and healthy lean controls, we assessed the colonic microenvironment through metabolomic, transcriptomic, and microbiome analyses. Colonic organoids were cultured to further explore epithelial alterations. Additionally, human MetS fecal metabolomics data were cross-compared with the mouse model to validate translational relevance. MetS mice exhibited upregulation of colonic anabolic pathways, including glycolysis, the pentose phosphate pathway, and the tryptophan/kynurenine pathway, without evidence of intestinal inflammation. Microbiome analysis revealed an increased abundance of the genus Lactobacillus in MS NASH mice. Colonic organoids from MetS mice showed altered goblet cell differentiation. Comparative analysis with human MetS fecal metabolomics demonstrated similar dysregulated pathways, underscoring the translational relevance of these findings. Our study reveals significant metabolic and microbial alterations in the colon of MS NASH mice, implicating a dysfunctional GI tract as a potential etiological factor in MetS. These findings highlight specific metabolic pathways and microbial signatures that could serve as future therapeutic targets for MetS. NEW & NOTEWORTHYThis study identifies the colon as a metabolically active tissue affected in metabolic syndrome. Despite the absence of intestinal inflammation, MS NASH mice displayed altered colonic metabolism and microbiota composition, with conserved metabolite changes matching those seen in humans with metabolic syndrome. These findings highlight colonic metabolic dysfunction as a potential driver of gut dysbiosis and disease progression in metabolic syndrome and MASLD. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/716131v1_ufig1.gif" ALT="Figure 1"> View larger version (77K): org.highwire.dtl.DTLVardef@1b7c685org.highwire.dtl.DTLVardef@4a832aorg.highwire.dtl.DTLVardef@1e95c66org.highwire.dtl.DTLVardef@1b14209_HPS_FORMAT_FIGEXP M_FIG C_FIG

Altered iron homeostasis has long been implicated in Parkinson's Disease (PD), although the mechanisms have not been clear. Given the critical role of PD-related activating mutations in LRRK2 (leucine-rich repeat protein kinase 2) within membrane trafficking pathways we examined the impact of a homozygous mutant LRRK2G2019S on iron homeostasis within the RAW macrophage cell line with high iron capacity. Proteomics analysis revealed a dysregulation of iron-related proteins in steady state with highly elevated levels of ferritin light chain and a reduction of ferritin heavy chain. LRRK2G2019S mutant cells showed efficient ferritinophagy upon iron chelation, but upon iron overload there was a near complete block in the degradation of the ferritinophagy adaptor NCOA4. These conditions lead to an accumulation of phosphorylated Rab8 at the plasma membrane, which is selectively inhibited by LRRK type II kinase inhibitors. Iron overload then leads to increased oxidative stress and ferroptotic cell death. These data implicate LRRK2 as a key regulator of iron homeostasis and point to the need for an increased focus on the mechanisms of iron dysregulation in PD.

This study aimed to examine whether Humanin-G (HNG), a mitochondrial derived peptide with cytoprotective properties, could improve the retinal function and gene expression profiles after intraperitoneal injections to Royal College of Surgeons (RCS) rats with Retinal Pigment Epithelium (RPE) dysfunction and retinal degeneration. Starting at postnatal day 21 (p21), RCS rats received twice a week intraperitoneal injections of either Low Dose HNG (0.4 mg/kg), High Dose HNG (4mg/kg), or sham-saline for 1 or 4 weeks. Visual function was tested with full field scotopic & photopic electroretinography (ERG) and optokinetic testing (OKT) 1 and 4 weeks after first injection (WAFI). The rats were euthanized after the ERG and OKT (1 or 4 WAFI) and the dissected retinas and RPE were collected for RNA, cDNA and Quantitative Real-time PCR (qRT-PCR) analysis. The results of our study showed that high dose (4mg/kg) HNG at 4 WAFI was associated with the largest change in gene expression in the RPE and retina of treated animals, altering expression of genes involved in apoptosis, oxidative stress, inflammation and retinal/RPE function. Analysis of a and b waves from scotopic and photopic ERG showed no difference between either low or high dose of HNG and sham injection at 4 WAFI. However, at 4 WAFI, the visual acuity in rats treated with high dose HNG showed significant improvement as compared to the rats treated with low dose of HNG or saline. Most significantly, our findings support that HNG administered IP can modulate RPE/neuroretina cells and improve vision, thus may be a potential treatment for retinal degeneration diseases.

PurposeAnti-vascular endothelial growth factor (anti-VEGF) therapy is the standard of care for neovascular age-related macular degeneration (AMD), yet many patients exhibit persistent retinal degeneration, fibrosis, and incomplete therapeutic response. The molecular pathways underlying this incomplete response remain poorly understood. We sought to identify VEGF-independent signaling pathways active in the vitreous of anti-VEGF-treated AMD patients. MethodsWe performed multiplex antibody-based proteomic profiling of 1,000 human proteins in vitreous samples from patients with neovascular AMD receiving anti-VEGF therapy (n=8) and comparative controls (n=6). Differential protein expression was assessed using one-way ANOVA, followed by gene ontology and pathway enrichment analyses. Drug-target relationships were evaluated to identify potential opportunities for therapeutic repositioning. ResultsWe identified 107 differentially expressed proteins (p<0.05), including key regulators of immune signaling, angiogenesis, and metabolism. Notably, multiple components of cytotoxic lymphocyte pathways were dysregulated, including IL-21R, SIGLEC-7, CTLA4, and IL-2-associated signaling. Enrichment analyses revealed significant activation of pathways related to T-cell activation, interleukin signaling, and leukocyte-mediated cytotoxicity. These immune signatures persisted despite suppression of VEGF signaling. Several clinically available immunomodulatory agents--including abatacept, sirolimus, and dupilumab--targeted pathways identified in this dataset. ConclusionsAnti-VEGF-treated neovascular AMD exhibits persistent cytotoxic immune signaling in the vitreous, suggesting that VEGF-independent immune mechanisms may contribute to ongoing retinal damage and incomplete therapeutic response. These findings provide a rationale for combination therapeutic strategies targeting both angiogenic and immune pathways in AMD.

Age-related macular degeneration (AMD) is a common, complex disease affecting older individuals that can lead to severe vision loss. It is characterized by early anatomical changes in the retina, retinal pigment epithelium (RPE), and choroid, especially in the central (macular) region. AMD can progress to severe atrophy and/or pathologic angiogenesis that leads to visual decline. Over 30 genetic loci have been identified as contributing to AMD risk; however, the mechanisms by which genetic variants affect pathology has not been thoroughly explored. In this report we examined single-nucleus gene expression in the retina, RPE and choroid of 88 individuals categorized by AMD stage, as well as 37 previously published samples. Genotyping was performed on 1.8 million SNPs, with additional SNPs imputed, on each donor to identify expression quantitative trait loci (eQTLs). We found that two AMD-risk loci (PILRB and ARMS2/HTRA1) affected the expression of PILRB and HTRA1, respectively. The risk allele of PILRB was associated with increased PILRB RNA in cones, fibroblasts, choroidal macrophages, and RPE, whereas the HTRA1 risk locus was associated with decreased HTRA1 RNA in the RPE. We also identified an age-related decrease in complement inhibitors in the choriocapillaris, a tissue susceptible to complement mediated damage in AMD.

Background & AimsClonal hematopoiesis of indeterminate potential (CHIP) has been linked to chronic liver disease progression, yet its role across the full spectrum of metabolic dysfunction-associated steatotic liver disease (MASLD), from its initial development to end-stage complications, remains unclear. We aimed to comprehensively investigate the association of CHIP and its major subtypes with both the incidence and progression of MASLD. MethodsWe conducted a prospective cohort study of 353,218 UK Biobank participants, stratified into a healthy cohort free of MASLD at baseline (Cohort 1; n=230,270) and a prevalent MASLD cohort (Cohort 2; n=122,948). CHIP was ascertained from whole-exome sequencing data. We used multivariable Cox regression, competing risk models, and mediation analyses to assess the associations of CHIP (overall, by driver gene, and by clone size) with incident MASLD, cirrhosis, hepatocellular carcinoma (HCC), and liver-related death. ResultsIn Cohort 1, CHIP was associated with an increased risk of incident MASLD (HR 1.25, 95% CI 1.08-1.44) and cirrhosis (HR 1.57, 95% CI 1.10-2.25). These associations were driven by non-DNMT3A mutations, particularly TET2, and showed a linear dose-response relationship with clone size. In Cohort 2, non-DNMT3A CHIP was associated with progression to cirrhosis (HR 1.82, 95% CI 1.28-2.58). The associations were more pronounced in males and in individuals without obesity or diabetes. C-reactive protein partially mediated the CHIP-MASLD association. ConclusionCHIP, driven predominantly by non-DNMT3A mutations (particularly TET2) is an independent risk factor for both the development and progression of MASLD. These findings position CHIP as a novel player in the pathophysiology of MASLD and suggest potential avenues for risk stratification and targeted anti-inflammatory intervention. Impact and ImplicationsThis large-scale, prospective study establishes clonal hematopoiesis of indeterminate potential (CHIP) as a novel and independent risk factor for the entire spectrum of metabolic dysfunction-associated steatotic liver disease (MASLD), from its initial development to its progression to cirrhosis and liver-related death. For hepatologists and hematologists, these findings identify a genetically defined, high-risk subpopulation, particularly individuals with non-DNMT3A mutations, who may benefit from enhanced liver surveillance. The identification of systemic inflammation as a partial mediator of the CHIP-MASLD association suggests that anti-inflammatory therapies currently under development for liver disease could represent a targeted treatment strategy for this growing patient population.

The Alzheimers Amyloid Precursor Protein (APP) has determinant roles in neuronal development and function, both in its full-length conformation and as some of its proteolytic peptides, particularly secreted (s)APPa. Given that APP phosphorylation tightly regulates its trafficking, proteolysis, and protein-protein binding, it consequently affects several APP functions. The S655 residue, located in the basolateral sorting motif YTSI at APP C-terminus has been observed to be phosphorylated in mature full-length APP and its C-terminal fragments. Previously observed to modify APPs protein interactions, resulting in altered endolysosomal trafficking, andincreased half-life and sAPPa generation, phosphoS655 APP has potential to modulate APP-mediated neuronal differentiation. To study the phosphoS655 differential interactome relevant for neuronal differentiation, SH-SY5Y cells expressing Wt or S655 phosphomutants APP-GFP were differentiated at two time points. APP-GFP and their respective interacting partners were immunoprecipitated using GFP-trap, and interactors identified by mass spectrometry. Both dephospho and phosphoS655 interactomes were generally enriched in similar processes, primarily RNA processing and translation, as well as signal transduction, metabolism, and cytoskeleton remodeling. The smaller phosphoS655 interactome contributes for functional specialization via binding to e.g. FUBP3, ELAVL4, ATXN2, Tubulin, INA. Several of these specific binding partners are known to promote neurite outgrowth and likely underlie our experimental observation that phosphoS655 APP promotes neuritogenesis, particularly the formation of longer neuritic extensions. These results are not only important for the body of knowledge on this Alzheimers disease core protein, but may also aid in future therapies against this disease.

CRX is a transcription factor essential for photoreceptor differentiation and functional development. Two missense mutations in CRX homeodomain, CRXE80A and CRXK88N, are linked to early-onset dominant retinopathies. Molecular studies have revealed distinct profiles of perturbed gene expression in differentiating photoreceptors of knock-in mouse models, resulting from altered DNA binding activities of mutant CRX proteins. This study characterizes concurrent retinal and vascular alterations in knock-in mouse models. Fated cones are present in heterozygous and homozygous CrxE80A and CrxK88N mutants at birth, but subsequent cone differentiation is rapidly compromised. Expression of rod marker rhodopsin (RHO) is absent in CrxK88N/Nretinae but present in other mutants through adulthood. Notably, as compared to wildtype controls, RHO expression is prematurely activated in neonatal CrxE80A mutants. Among tested mutants, only CrxE80A/+retinae elaborate rod outer segments but still lose visual function by young adulthood. The presence of irregular retinal rosettes is a striking pathological phenotype in all mutants. Retinal rosettes displace the localization of inner neurons without affecting their cell numbers during retinal development. Retinal vessels develop close contact with rosette structures. In summary, disrupted photoreceptor differentiation leads to the loss of visual function and formation of retinal rosettes. The presence of retinal rosettes secondarily impairs the localization of inner neurons and vasculature. A deeper understanding of these cellular underpinnings will inform pathogenesis of CRX homeodomain mutations.

Down syndrome (DS) results from trisomy for human chromosome 21 and is the most frequent genetic cause of intellectual disability. No effective treatments currently exist that improve neurodevelopment and cognition. Atypical brain development in individuals with DS is apparent before birth, which suggests that the optimal time to begin administration of therapies is prenatally. Human neural progenitor cell (NPC) cultures provide a tractable in vitro model system to examine the effects of trisomy 21 (T21) on neurodevelopment and to measure the effects of pharmacological interventions. Here we report the results of preclinical studies evaluating 24 candidate therapies. RNA-Seq analyses found that euploid and T21 NPCs showed different transcriptomic responses to five candidate pharmacotherapies. The Rho-associated coiled-coil kinase (ROCK) inhibitor fasudil increased proliferation of T21 NPCs, reduced expression of inflammatory pathway genes in T21 NPCs, and reduced markers of inflammation in LPS-stimulated microglia model systems. These results demonstrate that fasudil can alter multiple T21-associated abnormalities in a beneficial manner, suggesting that fasudil warrants further study as a candidate prenatal pharmacotherapy for DS.

Lacritin is an abundantly expressed glycoprotein in tear fluid and plays key roles in immune response, tear secretion, and bacterial killing. These biological functions are tightly regulated through several biochemical mechanisms including multimerization, proteolysis, and alternative splicing, especially within its C-terminal domain. Given its critical role at the ocular surface, lacritin is currently under investigation as a diagnostic biomarker and therapeutic candidate for dry eye disease (DED). However, despite over three decades since its initial discovery, the functional significance of the O-glycans that comprise more than 50% of its molecular weight remain largely unknown. To address this gap, we leveraged mass spectrometry (MS)-based glycoproteomics and molecular dynamics (MD) to explore the structural role of site-specific O-glycans on C-terminal lacritin. In doing do, we identified distinct glycosylation profiles between monomeric and multimeric lacritin, particularly at glycosites located near crosslinking residues (Lys101 and Lys104) that modulate multimer formation. Building on our glycoproteomics data, we performed MD simulations on monomer and multimer glycoforms and revealed that O-glycans participate in intra-glycan-protein interactions, thereby affecting the conformational flexibility of lacritin and the spatial arrangement of Lys101 and Lys104. Finally, we quantified the solvent-accessible surface area (SASA) of Lys101 and Lys104, highlighting that proximal O-glycosylation is predicted to affect the propensity of these residues to participate in crosslinking. Taken together, these findings underscore a central role for lacritin O-glycans in affecting structural topology with implications for its downstream biological activity.

Metabolic dysfunction-associated steatohepatitis (MASH) is associated with increased expression of peroxisome proliferator-activated receptor gamma (PPAR{gamma}, Pparg) and reduced expression of genes involved in methionine metabolism in the liver. The nuclear receptor PPAR{gamma} is activated by fatty acids, and the knockout of Pparg in hepatocytes (Pparg{Delta}Hep) reduced the negative effects of MASH on methionine metabolism. Here, we sought to determine whether hepatocyte Pparg is required for the transcriptional regulation of genes involved in hepatic methionine metabolism in conditions with altered fatty acid flux to the liver: fasting, refeeding, and high-fat diet (HFD)-induced obesity/steatosis. Fasting induced liver steatosis and increased the expression of key genes involved in the methionine metabolism in the liver, while 6h-refeeding reversed these effects and reduced the expression of phosphatidylethanolamine N-methyltransferase (Pemt) and cystathionine beta synthase (Cbs). Overall, fasting and refeeding did not alter hepatocyte Pparg expression nor Pparg{Delta}Hep affected fasting and refeeding-mediated regulation of methionine metabolism gene expression. Diet-induced steatosis reduced hepatic Pemt expression in control (Pparg-intact) mice, and the thiazolidinedione (TZD)-mediated activation of PPAR{gamma} in diet-induced obese control (Pparg-intact) mice reduced the expression of betaine homocysteine S-methyltransferase (Bhmt) and Cbs. However, diet-induced steatosis increased hepatocyte Pparg expression, and Pparg{Delta}Hep blocked the negative effects of HFD and TZD on hepatic methionine metabolism. The PPAR{gamma}-dependent reduction of hepatic Bhmt and Cbs expression was confirmed in mouse primary hepatocytes. Taken together, hepatocyte Pparg may serve as a negative regulator of hepatic methionine metabolism in diet-induced obese mice and these actions could contribute to promoting the onset of MASH.

Lipodystrophies are a group of disorders featuring reduced adipose tissue mass or function, which often leads to significant metabolic disease, reduced lifespan and impaired quality of life. Individuals with congenital generalised lipodystrophy (CGL) have severely reduced adipose tissue mass. The loss of healthy systemic lipid storage typically causes hepatic steatosis and lipoatrophic diabetes. In addition, adipocyte-secreted hormones including leptin and adiponectin are dramatically reduced. Leptin has critical roles regulating appetite and broader effects on lipid and glucose metabolism. Daily injection with recombinant leptin is currently the only specific, approved treatment for CGL. The consequences of adiponectin loss in these patients are not fully understood. Likewise, the potential therapeutic benefit of adiponectin delivery is unclear. Here we examine the effect of delivering leptin or adiponectin by adeno-associated virus (AAV) as potential gene therapy treatment for metabolic disease in CGL using a well-characterised murine model of the condition. AAV-mediated leptin delivery significantly improved hepatic steatosis and hyperinsulinemia. However, adiponectin delivery did not lead to any observed beneficial effects. This demonstrates the potential of gene therapy approaches for long-term delivery of leptin in individuals with lipodystrophy, without the need for continuous supply of perishable therapeutics and painful daily injections.

Strabismus, or misalignment of the eyes, is a heritable disorder frequently associated with vision loss and decreased quality of life. Incomitant strabismus, where the degree of misalignment differs based on gaze angle, can arise from mutations in genes that regulate the development of extraocular motor neurons. To date, few such genes have been identified. The extraocular motor system is highly conserved across vertebrates, suggesting a comparative transcriptomic discovery approach would be fruitful. Using bulk and single-cell sequencing in a small accessible vertebrate, the larval zebrafish, we identified genes expressed in subpopulations of extraocular motor neurons in cranial nuclei nIII/nIV. We next assessed extraocular motor neuron number and vestibulo-ocular reflex performance after CRISPR/Cas9-mediated mutagenesis of three genes with suggestive expression patterns: sim1a, nav2a, one-cut1, and one known to disrupt nIII/nIV motor neuron specification: phox2a. Loss of sim1a impaired the vestibulo-ocular reflex without change to nIII/nIV motor neuron number. Our data suggest that constitutive disruptions to sim1a can impair nIII/nIV-dependent eye movements. More broadly, our work illuminates considerable transcriptomic diversity among extraocular motor neuron subpopulations, and establishes a pipeline to identify genes relevant to ocular motor disease etiology.

Frailty is a prevalent geriatric syndrome, and the shortage of objective biomarkers restricts its early diagnosis and intervention. This study aimed to identify robust molecular signatures and diagnostic markers for frailty using bioinformatics analyses of multiple independent datasets. Two transcriptome datasets (GSE144304, n=80; GSE287726, n=70) were obtained from the GEO database. We performed differential gene expression analysis, GO, KEGG and GSEA enrichment, and machine learning (70% training / 30% validation) to screen and validate core biomarkers. Numerous shared differentially expressed genes were identified. Vitamin D metabolism, ABC transporter, and inflammatory/immune pathways were consistently enriched and confirmed by GSEA. Machine learning models based on these signatures showed favorable diagnostic performance. Our study demonstrates that vitamin D metabolic disorders and chronic inflammation are core molecular features of frailty. The identified biomarkers provide new strategies for basic research, early clinical diagnosis, and therapeutic target development for frailty.

Mast cells (MCs) are myeloid cells of the innate immune system. As a first line of defence they fulfill effector functions and immune modulatory properties. Upon activation they release pro-inflammatory mediators such as cytokines and proteases. It has been suggested that MCs may contribute to the development of liver fibrosis. However, investigating hepatic MC biology in mice is challenging due to low MC numbers and a lack of suitable detection techniques relying on MC proteins and their modifications. Here, we evaluated whether the expression strength of MC markers correlates with the degree of liver fibrosis in mice and aimed to determine the frequency and localization of hepatic MCs. We applied both a toxic (DEN/CCl4 treatment) and a genetic (Mdr2-/- mice) liver fibrosis model in C57BL/6 mice and found a significant correlation between fibrosis grade and the expression of several established mast cell markers. This correlation was further supported in patients with fibrosis and hepatocellular carcinoma (HCC) using publicly available transcriptomics datasets. We used FACS to purify and isolate MCs from fibrotic mouse livers and verified MC signatures by qPCR analysis of MC-specific gene expression. Hepatic MCs were predominantly negative for Mast-Cell-Protease 5 (Mcpt5) and occurred at a low frequency (approximately 1-2% of leukocytes). Using Molecular CartographyTM of fibrotic liver sections, we determined the spatial localization, expression signature, abundance (approximately 2 cells/mm2) and cellular environment of murine hepatic MCs. In summary, we demonstrated the existence of MCs in murine fibrotic livers and defined an MC expression signature that correlates with the strength of liver fibrosis. These findings will help to study MC biology in murine models of liver disease more effectively in the future.

Age-related macular degeneration is a common ocular disease that causes vision loss in the elderly, with a complex set of risk factors and proposed mechanisms of pathogenesis. A powerful method for investigating changes in disease is metabolomics, by which small molecules can be identified and quantified simultaneously. We report here the metabolic analysis of human RPE-choroid tissue in aging and macular degeneration (AMD), as well as comparisons of human macular and extramacular RPE-choroid and neural retina. Levels of 215 metabolites were determined in young donors, AMD donors (early/intermediate, geographic atrophy, and neovascularization) and age-matched controls. The largest number of metabolite differences were observed between young and healthy aged controls, as opposed to between aged controls and any stage of AMD. Two notable metabolites found to be increased in aging choroids are trimethylamine N-oxide and uric acid, both of which were significant after Bonferroni correction. A mouse endothelial cell line treated with a high concentration of uric acid exhibited reduced migration in a wound closure assay. This study provides initial insights into the metabolome of human choroids in varying states of age and macular degeneration, as well as functional implications of these changes in the aging choroid.

Recurrent hypoglycemia increases cognitive impairment in diabetes mellitus patients. Following cerebral neuron injury, endothelial cells provide morphological, metabolic and immune support to damaged neurons. We investigated the inflammatory mechanism involved in hippocampal neuron degeneration. Behavioral experiments, including the open field test (OFT) and the Morris water maze test, were performed to measure cognitive changes. Using a vascular ring experiment, we evaluated vasodilation of the carotid artery. ZBP1 expression was knocked down after transfection with small interfering RNA in a brain endothelial cell line (bEnd3). In this study, PANoptosis, a recently defined form of programmed cell death (PCD), was found to be increased by hypoglycemia in the hippocampus of type 2 diabetic mice in vivo and by low glucose in bEnd3 cells in vitro. ZBP1 knockdown decreased PANoptosis induced by low-glucose stimulation in high-glucose-cultivated bEnd3 cells. RNA transcriptomics sequencing revealed that AGE-RAGE signaling significantly changed after ZBP1 was knocked down in bEnd3 cells. Corresponding biochemical data confirmed that ZBP1 knockdown regulated the advanced glycation end products (AGEs)-Receptor for Advanced Glycation End Products (RAGE) axis in bEnd3 cells. We present the first evidence that hypoglycemia impaired cognition in mice with type 2 diabetes by activating brain endothelial ZBP1-mediated PANoptosis via the AGE-RAGE axis. ARTICLE HIGHLIGHTSO_LIPANoptosis, a newly defined form of programmed cell death, is induced in the hippocampus after recurrent hypoglycemia in male db/db mice. C_LIO_LIZBP1, a sensor of the PANoptosome, was activated in low glucose cultured brain endothelial cells. C_LIO_LIHypoglycemia impairs vasodilation and cognitive function in type 2 diabetic mice. C_LIO_LIOur study indicates that inhibiting ZBP1-PANoptosis and the AGE-RAGE axis may be a potential approach to prevent hypoglycemia-induced cognitive degeneration in individuals with type 2 diabetes. C_LI

Metabolic dysfunction-associated steatotic liver disease (MASLD) afflicts more than one-third of adults globally, contributing significantly to an increased cardiovascular disease risk. Further, patients with severe liver disease experience muscle weakness (sarcopenic obesity) and fatigue. Hypoxia-inducible factor 2 (HIF2) accumulates in the livers of MASLD patients and has been implicated in disease progression. Here we sought to understand the role of hepatic HIF2 in mediating hepatic and extra-hepatic features of MASLD. Using a well-validated obese mouse model of MASLD, we investigated the impact of hepatocyte-specific HIF2 deletion (hHIF2-/-) on hepatic, cardiac and skeletal muscle metabolism, and cardiac function. Over 28 weeks, mice were exposed to a high-fat, high-fructose, high-cholesterol (GAN) diet, which induced obesity alongside hepatic steatosis, fibrosis and inflammation. In contrast to observations in lean mouse models of liver disease, hHIF2-/- did not protect against MASLD, despite greater hepatic NADH-supported mitochondrial respiration and higher intracellular sphingomyelin levels. Instead, in the hearts of GAN-fed mice, hHIF2-/- caused diacylglycerol accumulation independent of diet, accumulation of long-chain acyl-carnitines and exacerbation of ceramide accumulation. Langendorff-perfused hearts from hHIF2-/- mice showed systolic and diastolic dysfunction, including 24% lower left ventricular developed pressure and 34% lower maximal rate of relaxation (dP/dtmin). However, isolated hearts from hHIF2-/- mice were protected against MASLD-associated sympathetic dominance, determined using autonomic receptor agonist stimulation. Both GAN-feeding and hHIF2-/- were associated with lower lean mass (14% and 5.4% lower than respective controls), whilst hHIF2-/- enhanced OXPHOS-associated protein levels in gastrocnemius muscle. Overall, hHIF2-/- resulted in detrimental extra-hepatic effects, including myocardial lipid accumulation, impaired cardiac function, and loss of whole-body lean mass, with no apparent protection against MASLD disease progression.

The use of decellularized diseased livers in regenerative medicine is a promising approach for eliminating organ shortages. Bioengineering studies have shown that ECM can impact cell physiology, inducing cell activation, function, and ECM deposition, which suggests that the ECM has a "memory" that is involved in the outcome after recellularization. However, the effect of diseased ECM memory on new cells in vitro and in vivo has not been thoroughly investigated. Since it has been increasingly recognized that liver ECM changes due to different factors, it is comprehensively that diseased ECM obtained from discarded organs will ensure a distinct environment and impact cell survival and physiology. Thus, we aimed at investigating the impact of the memory of diseased ECM obtained from metabolic dysfunction-associated steatohepatitis (MASH)-derived organs on steatohepatitis establishment. To address this aim, we explored decellularized ECM obtained from rats and humans with MASH in different contexts. First, MASH ECM was characterized and then submitted to transplantation to investigate whether a MASH-derived ECM could be used as a scaffold for transplantation and to promote steatohepatitis features in control animals. Histological analysis revealed that the MASH-ECM was completely recellularized after transplantation in both control and MASH recipient rats. However, steatosis and fibrosis were observed in MASH ECM after transplantation in both groups. Molecular analysis showed that MASH ECM stimulates de novo lipogenesis and fibrosis 30 days after transplantation. Untargeted metabolomic analysis revealed that cells grown on MASH ECM had a similar metabolic profile, even when transplanted into healthy or MASH recipient rats. In addition, we observed that MASH ECM promoted impaired lipid oxidation and mitochondrial dysfunction when transplanted into healthy recipients. Altered lipid turnover and inflammatory signaling were observed in MASH ECM transplanted in MASH recipients. In vitro analysis revealed that MASH ECM induced lipid accumulation in HepG2 cells after 10 days of culture. Calcium signalling experiments obtained from HepG2 cells cultured in MASH ECM showed a lower response to ATP, a reduced calcium signalling amplitude, and a distinct response profile than that observed in healthy ECM. On the other hand, a diseased human-derived ECM could still provide an environment that allows cell development. Taken together, our data showed that MASH ECM impacts cell metabolism, promoting steatohepatitis maintenance. In conclusion, our data confirm that diseased ECM memory can impact cell physiology contributing to disease progression.