Journal of Cellular Physiology

Adverse cardiac remodeling following myocardial infarction (MI) are driven by processes including autophagy and apoptosis. While microtubule-associated protein 1S (MAP1S) is known to regulate autophagy, its role in the cardiac pathological conditions remains unclear. This study aimed to elucidate the role of MAP1S and its underlying mechanisms in pathological cardiac remodeling. Following MI, MAP1S knockout mice exhibited increased mortality, impaired cardiac function, and elevated apoptosis. Similarly, MAP1S silencing in cultured cardiomyocytes augmented apoptosis under oxidative stress. Mechanistic investigation revealed potential link to the Hippo pathway. MAP1S knockdown in cardiomyocytes increased Mammalian Ste-20 like 1/2 (MST1/2) activation and reduced Yes-associated protein (YAP) activity, potentially explaining apoptosis regulation. Conversely, MAP1S overexpression reduced apoptosis and positively modulated autophagy. Importantly, in vivo modRNA-mediated MAP1S overexpression protected against apoptosis and adverse remodeling. This study reveals that MAP1S protects the heart from excessive apoptosis and adverse remodeling following MI, likely by modulating the Hippo signaling pathway.

Skeletal muscle is a dynamic tissue able to regenerate in response to injury. This regeneration relies primarily on the activation of precursor cells, known as muscle stem cells (MuSC). Upon activation, skeletal MuSC re-enter the cell cycle and proliferate as myoblasts, which subsequently either differentiate and fuse to form new fibers or return to quiescence to maintain long-term regenerative capacity. From primary human myoblasts, we generated reserve cells (RCs), quiescent cells similar to MuSC, and investigated their activation after stimulation with a growth medium containing serum. Here, we show that Orai3 calcium channel is primarily expressed in RC, where it promotes RC activation in a calcium-independent manner. We demonstrate that Orai3 does not contribute to store-operated calcium entry (SOCE) or calcium response induced by serum stimulation in RC cells, supporting the hypothesis that Orai3 plays a unique role in RC, distinct from its calcium channel activity. Using a protein proximity assay (BioID), we identified the large scaffold protein AHNAK2 as a potential partner of Orai3. AHNAK2 is expressed at high level in myotubes, and has a similar effect on RC activation than Orai3. Both Orai3 and AHNAK2 are necessary for proper myoblast differentiation and RC activation, while acting through different signaling pathways. Specifically, we show that Orai3 directly influences the RC fate, whereas AHNAK2 facilitates RC activation via signals derived from myotubes. These findings provide new insights into the molecular mechanisms underlying the activation and quiescence of human MuSC.

Background: Ion channels regulate mammalian sperm function, yet chloride channels have received less attention than their cation counterparts. Herein, we investigated the presence, localization, and function of voltage-gated chloride channels (ClC-1, ClC-2, and ClC-K) and calcium-activated channels (ANO1 and ANO2) during sperm capacitation and the acrosome reaction. Results: Using the pig as an animal model, we localized these channels in different sperm regions: ClC-1 in the equatorial and post-acrosomal regions; ClC-2 in the connecting and principal pieces; ClC-K in the acrosome, connecting, and principal pieces; ANO1 in the principal piece; and ANO2 in the mid-piece and post-acrosomal sheath region. Following this, we addressed the roles of these channels in sperm capacitation and acrosome reaction by blocking them with different inhibitors: 9AC, specific for ClCs; BBR, specific for CaCCs; and NPPB, a broad-spectrum blocker that inhibits ClCs, CaCCs, and other chloride channels. Blocking CaCCs with BBR led to a significant reduction in sperm motility and mitochondrial membrane potential, with effects similar to those of the non-selective inhibitor NPPB or to a combination of BBR and NPPB. Moreover, although none of the three inhibitors affected intracellular calcium levels or acrosomal integrity, a significant reduction in protein tyrosine phosphorylation was observed in sperm treated with the combination of NPPB and BBR. Finally, membrane lipid disorder was increased when ClCs were blocked with 9AC and when sperm were incubated with a combination of BBR and NPPB. Conclusions: Our results suggest that CaCCs play a major role in sperm capacitation compared to ClCs. Further research to address the regulatory mechanisms involved and the potential relationship with other ion channels is warranted.

Capacitation is a post-ejaculatory maturation process by which sperm become hyperactive and undergo the acrosome reaction, both of which are required to fertilize an oocyte. Two key features of capacitation are increased intracellular calcium via the calcium channel CatSper and changes in mitochondrial function. In mouse spermatozoa, CatSper-dependent calcium entry promotes mitochondrial calcium uptake and mitochondrial activation, contributing to hyperactivated motility and fertilization ability. Whether this mechanism is conserved in human spermatozoa was unknown. Here, we assessed mitochondrial function and mitochondrial calcium in paired non-capacitated and capacitated human spermatozoa from normozoospermic donors. Capacitation increased mitochondrial respiratory control ratio, coupling efficiency, mitochondrial membrane potential, and mitochondrial calcium. The increase in mitochondrial calcium required extracellular calcium and was prevented by pharmacological inhibition of CatSper or the mitochondrial calcium uniporter (MCU). Inhibition of CatSper or mitochondrial calcium uniporter also attenuated the capacitation-associated increase in mitochondrial membrane potential and reduced hyperactivated motility without affecting progressive or total motility. Pharmacological disruption of mitochondrial function reduced capacitation-associated hyperactivated motility without affecting the acrosome reaction. Together, these findings support a conserved pathway in human and mouse spermatozoa in which CatSper-mediated calcium entry promotes MCU-dependent mitochondrial calcium uptake and mitochondrial activation, contributing to the acquisition of hyperactivated motility during capacitation. These findings identify mitochondrial calcium handling as a potential target for modulating human spermatozoa function.

Collective cell migration is a fundamental process driving tissue repair, angiogenesis, and vascular homeostasis. This coordinated movement requires both intercellular communication via gap junctions and precise intracellular Ca{superscript 2} signaling, largely regulated by the sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) pump within the endoplasmic reticulum (ER). Historically, carbenoxolone (CBX)--a synthetic derivative of glycyrrhetinic acid--has been widely utilized as a pharmacological tool to inhibit gap junctions and dissect their role in collective cell motility. However, its molecular specificity remains highly controversial. In the present study, using different cellular models, we found that CBX drastically reduces collective cell migration by a previously undescribed function for CBX: a fast, potent, and reversible inhibition of the SERCA pump, which provokes a passive leak of the luminal ER Ca{superscript 2} store. Our findings suggest that the effect of CBX over many cellular responses including cell migration and communication, previously only attributed to gap junction blockade, are indeed the consequence of the disruption of intracellular Ca{superscript 2} homeostasis. One Sentence Summarycarbenoxolone blocks cell migration by inhibiting SERCA

Arginine vasopressin (AVP) increases excitability of myometrial smooth muscle cells (MSMCs) through Gq-coupled AVP receptors. Although excitability requires membrane depolarization, the mechanisms linking AVP receptor activation to membrane depolarization and Ca{superscript 2} signaling are incompletely understood. Here, we show that AVPR1 is the predominant AVP receptor in primary MSMCs. In Xenopus oocytes, AVP signals through AVPR1 to inhibit SLO2.1-mediated potassium currents, reducing current amplitude to approximately 60% of control currents. Consistent with suppression of a hyperpolarizing conductance, AVP depolarized a myometrial cell line (hTERT-HM) and increased intracellular Ca{superscript 2} signaling. Analysis of Ca{superscript 2} dynamics revealed that the initial Ca{superscript 2} peak was largely preserved under conditions limiting extracellular Ca{superscript 2} entry, consistent with intracellular store release. Conversely, the oscillatory phase depended on extracellular Ca{superscript 2} influx and was reduced by SLO2.1 knockdown. Together, these findings support a model in which AVP preferentially signals through AVPR1A to inhibit SLO2.1, depolarize myometrial cells, enhance VDCC-dependent Ca{superscript 2} entry, and promote excitability, enhancing conditions for uterine contraction.

RASAL3 acts as a negative regulator of small cellular GTPases in hematopoietic cells. In immune cells, it primarily modulates the RAS/MAPK signaling pathway and affects cellular events including proliferation, differentiation, survival, and migration. Due to its inhibitory role in T cells, RASAL3 may represent a potential modulatory target for improving therapeutic strategies such as cell-based immunotherapy. However, most existing knowledge about RASAL3 function is derived from murine models, and its role in human T-cell signaling remains insufficiently characterized. To address this gap, we systematically investigated the function of RASAL3 in human primary T cells and T-cell line. For this purpose, we employed RASAL3 overexpression, CRISPR/Cas9-mediated deletion, and siRNA-mediated knockdown to thoroughly analyze the effects of RASAL3 on T-cell signaling, proliferation, and migration. Our data demonstrate that RASAL3 modulates primarily CDC42 and RAC1/RAC2 GTPases activity, SAPK/JNK phosphorylation, c-Fos and c-Jun expression, and IL-2 gene promoter activation. In addition, RASAL3 regulates actin polymerization and T-cell migration. Notably, loss of RASAL3 increases Jurkat T cells motility in vivo and potentiates their homing to the spleen. Collectively, these findings identify RASAL3 as an important regulator of human T-cell activation and motility and highlight its application potential for improving CAR-T cell therapy.

Neonatal mammals exhibit a remarkable capacity for cardiac repair that declines rapidly after birth and continues to diminish with age. This loss of regenerative potential is accompanied by age-dependent changes in macrophage behavior, shifting from pro-regenerative to pro-fibrotic responses following injury. We investigated whether extracellular matrix (ECM)-derived matrikines from different developmental ages regulate macrophage polarization. Cardiac ECM was isolated from neonatal (P2), adolescent (6-week), and adult (16-20-week) rat hearts through decellularization and pepsin digestion. ECM peptides were adsorbed onto tissue culture surfaces, and murine RAW 264.7 macrophages were cultured on ECM-coated or uncoated controls. After 24 hours, macrophage phenotype and gene expression were assessed using marker analysis and RNA sequencing. Macrophages cultured on neonatal cardiac ECM displayed reduced inflammatory activation and maintained expression of pro-reparative markers, even in the presence of inflammatory stimuli. Transcriptomic analysis revealed a distinct ECM-driven phenotype that differed from canonical M1 and M2 polarization states. Gene ontology analysis demonstrated significant downregulation of pathways associated with antiviral responses, immune activation, and interferon signaling in macrophages exposed to neonatal ECM. These effects were not observed with adolescent or adult ECM. Collectively, these findings suggest that neonatal ECM matrikines suppress interferon-mediated inflammatory signaling, potentially contributing to the reduced inflammation and enhanced repair observed following myocardial injury in neonatal hearts.

Store-operated calcium entry (SOCE) is a ubiquitous calcium (Ca2+) signalling mechanism that replenishes endoplasmic and sarcoplasmic reticulum Ca2+ stores. We previously identified STIM1L, a skeletal muscle-enriched STIM1 splice variant that enables rapid SOCE activation in human myotubes. To determine its physiological role in vivo, we generated a constitutive knockout mouse model that selectively abolishes STIM1L expression while preserving the canonical STIM1 isoform. Stim1l-KO mice developed normally and exhibited no overt abnormalities, but both sexes showed reduced voluntary wheel-running activity, suggesting neuromuscular perturbation. Skeletal muscle deprived of STIM1L did not show any histological alterations or changes in fibre- type and size. Likewise, force-frequency relationships and fatigue resistance measured ex vivo in isolated extensor digitorum longus and soleus muscles were indistinguishable from control muscles. This lack of difference may be explained by the increased expression of STIM1 in several skeletal muscles and suggests that changes in the voluntary running activity of Stim1l-KO mice may arise from STIM1L loss in non-muscular tissues, including the central nervous system. Notwithstanding, primary myotubes derived from Stim1l-KO mice displayed a marked delay in SOCE activation kinetics, whereas SOCE amplitude remained comparable to controls. This was consistent with a compensatory STIM1 upregulation maintaining overall Ca2+ entry capacity. Interestingly, electrically evoked Ca2+ transients in intact Stim1l-KO flexor digitorum brevis fibres exhibited significantly faster decay kinetics than controls. This revealed another role of STIM1L in Ca2+ handling in skeletal muscle that appears independent of its contribution to SOCE activation. Together, these findings establish STIM1L as a regulator of SOCE activation kinetics and indicate an additional role in myofibre Ca2+ clearance, while suggesting that compensatory upregulation of canonical STIM1 may preserve muscle structure and contractile function in its absence in mice.

Repetitive cytosolic Ca2+ spikes in pancreatic acinar cells, elicited by low (physiological) concentrations of acetylcholine (ACh), cholecystokinin (CCK) and gastrin releasing peptide (GRP), control secretion of digestive enzymes, whereas high-intensity stimulation induces sustained Ca2+ elevation initiating acute pancreatitis. Since inositol trisphosphate (IP3) was discovered as an intracellular Ca2+ releasing messenger, it has been assumed that a major class of G-protein coupled receptors relies on this pathway. We have now compared the mechanisms of action of the three physiological stimulants, all acting on different receptors, but each coupled to the IP3 pathway. Low concentrations of CCK and GRP cannot elicit Ca2+ signals without co-operation of an additional intracellular mechanism. CCK-elicited Ca2+ signalling requires activation of intracellular receptors for nicotinic acid adenine dinucleotide phosphate (NAADP), whereas this is not the case for the action of GRP that nevertheless relies on the operation of CD38, the enzyme involved in the synthesis of both cyclic ADP ribose and NAADP. Even Ca2+ signals elicited by ACh are partially dependent on CD38. It is engagement of these additional non-IP3 pathways that allows low concentrations of secretagogues to elicit safe Ca2+ spiking and therefore secretion, obviating the need for potentially toxic high levels of secretagogues.

Mitochondrial dysfunction and oxidative stress represent two interconnected, primary causes for Diabetic Neuropathy (DN); however, the majority of currently available anti-diabetic therapies have focused on glucose control as opposed to neurodegenerative downstream effects. Corilagin, is an ellagitannin having high anti-oxidant properties; however, it has not been evaluated against hyperglycemia induced neuronal injury. The present study demonstrates the ability of Corilagin to protect against mitochondrial dysfunction via models of diabetic nephropathy and cerebral ischemia. High glucose (50 mM, 24 hr) was utilized to induce diabetes like conditions in the SH-SY5Y human neuroblastoma Cell Line. High glucose induced significant decreases in cell viability, increases in intracellular and mitochondrial reactive oxygen species, depletion of reduced glutathione reserves, induces apoptosis, and causes mitochondrial depolarization and fragmentation. Corilagin pre-treatment attenuated each of these high-glucose induced effects by protecting against mitochondrial membrane potential loss and maintaining mitochondrial network morphology while reducing apoptotic cell fraction relative to glucose alone. Additionally, these protective effects were accompanied by restoration of AMPK phosphorylation and up-regulation of SIRT1, PGC1 and TFAM, components that are part of the principal signaling pathway that regulates mitochondrial biogenesis; therefore, therefore, this pathway may contribute mechanistically to the cyto-protective effect of Corilagin. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=99 SRC="FIGDIR/small/740444v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@1be4a92org.highwire.dtl.DTLVardef@11d6e9org.highwire.dtl.DTLVardef@1346757org.highwire.dtl.DTLVardef@16c9f1e_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstractC_FLOATNO Proposed mechanism underlying the neuroprotective effects of Corilagin against high glucose-induced mitochondrial dysfunction.High glucose suppresses AMPK phosphorylation, leading to downregulation of the SIRT1-PGC-1-TFAM signaling axis, increased intracellular and mitochondrial reactive oxygen species (ROS), glutathione depletion, apoptosis, mitochondrial depolarization, and mitochondrial fragmentation. Corilagin pretreatment restores AMPK activation and the downstream SIRT1-PGC-1-TFAM pathway, thereby reducing oxidative stress, preserving intracellular glutathione, preventing apoptosis, maintaining mitochondrial membrane potential, and protecting mitochondrial network integrity. C_FIG

Background. Cancer cachexia is a multifactorial syndrome characterized by substantial metabolic disturbances including systemic inflammation, and muscle atrophy, which may affect the regulation of iron metabolism in patients. This study aimed to characterize this regulation in two murine models of colorectal and pancreatic cancer, both associated with a high prevalence of cachexia. Methods. Histological, biochemical and molecular analyses were performed in serum, skeletal muscle, liver, spleen and tumor from UN-KC-6141 pancreatic tumor bearing mice and from ApcMin/+ mice (colorectal cancer model), both models exhibiting variable cachexia severity. Results. Both models induce cachexia, but diverge markedly in their regulation of iron metabolism. UNKC mice display reduced plasma iron availability (-9.6% transferrin saturation, p<0.001) without concomitant anemia, while hepatic hepcidin synthesis is upregulated (+100.6%, p<0.001) by inflammation, promoting ferroportin (FPN) downregulation (-42.4%, p<0.001) and iron sequestration in the spleen (+134% total iron content, p<0.001). In the atrophied gastrocnemius, iron concentration is preserved through increased ferritin (+86.6%, p=0.010) and hemoproteins (i.e., myoglobin, CYSC, COXIV) expression. Conversely, ApcMin/+ mice exhibit anemia together with hepatic and splenic iron depletion (-48.4%, p<0.001 and -84.9%, p<0.001, respectively). Hepcidin synthesis is downregulated (-99.9%, p<0.001) despite persistent inflammation, indicating that hypoxia and/or iron-deficiency signals probably predominate over the inflammatory pathway. FPN is markedly decreased (-94.2%, p<0.001) in the iron-depleted spleen despite low hepcidin. In the atrophied quadriceps of ApcMin/+ mice, iron deficiency is associated with decreased FPN and ferritin (-87.9%, p<0.001, and -38.4%, p=0.016, respectively), and increased TfR1 expression (+305%, p=0.107). Finally, tumor iron import may play a significant role in cachexia progression, as suggested by the association between tumor weight, tumor TfR1 protein levels and body weight loss in UNKC mice. Conclusion. These findings reveal cancer type-specific signatures of iron regulation in cachexia, which appear to be more driven by cancer type specific features than by cachexia severity itself, with skeletal muscle iron metabolism impaired mainly when cachexia is associated with anemia. This suggests that the clinical management of iron metabolism in cachectic patients should be guided by the underlying cancer type.

Colorectal cancer cells increase glycolysis to help meet the metabolic demands required for cell growth. Many factors, both endogenous and exogenous, likely drive cellular metabolism and enhance glycolytic flux in colorectal cells. Interleukin-1 beta (IL-1{beta}) is a pro-inflammatory cytokine that is elevated in colorectal cancer. In this study, we investigated the effect of IL-1{beta} toward driving the cancer cell to increase glycolysis, while also suppressing the oxidation of the fiber-derived nutrient butyrate. The results presented here demonstrate that IL-1{beta} stimulated glycolysis and inhibited maximal mitochondrial respiration. IL-1{beta} also increased the phosphorylation of AKT and hypoxia-inducible factor 1 alpha (HIF1) levels. Utilizing colorectal cancer cells with AKT1/2 or HIF1 knocked out showed the requirement of these proteins in mediating the increase in glycolysis following IL-1{beta} treatment. Importantly, AKT1/2 was identified as upstream of HIF1, as IL-1{beta} still increased phosphorylation of AKT even in the absence of HIF1. However, loss of AKT1/2 completely abolished the ability of IL-1{beta} to increase HIF1 protein levels. Tumor necrosis factor alpha (TNF), another cytokine found to be elevated in colorectal cancer, also increased glycolysis in an AKT and HIF1-dependent manner. Our data point to a common pathway through AKT activation and HIF1 upregulation, by which pro-inflammatory cytokines increase glycolysis in colorectal cancer cells to help promote cancer progression.

Protein misfolding in the endoplasmic reticulum (ER) of podocytes/glomerular epithelial cells (GECs) induces ER stress and contributes to the pathogenesis of glomerular disease. Activation of IRE1 and consequently the unfolded protein response (UPR) and autophagy sustains proteostasis. The present study examines the role of Surf4 and collagen IV-5 (COL4A5) trafficking in podocyte proteostasis. Glomerular Surf4 protein expression increased in IRE1-replete mice with experimental focal segmental glomerulosclerosis (FSGS) compared to podocyte-IRE1 knockout mice with FSGS and control mice. Glomerular Surf4 gene expression was greater in human FSGS and membranous nephropathy compared to healthy controls. In cultured GECs, basal Surf4 expression was greater in IRE1-replete (control) compared to IRE1 knockout GECs, although ER stress (tunicamycin treatment) did not increase Surf4 despite activating the UPR. Tunicamycin enhanced autophagy (LC3-II) in an IRE1-dependent manner, and the amount of Surf4 localized in autophagosomes. In GECs, tunicamycin increased the amount and colocalization of endogenous COL4A5 or ectopically-expressed COL4A5-wild type (WT) and Surf4 in autophagosomes. Compared to COL4A5-WT, the human COL4A5-C1567R mutant (which is misfolded) showed enhanced basal colocalization with Surf4 in autophagosomes; colocalization was similar to COL4A5-WT after tunicamycin treatment. Degradation of COL4A5-C1567R was more rapid compared to COL4A5-WT and was comparable to degradation of COL4A5-WT in the presence of tunicamycin. Thus, during ER stress, subsets of Surf4 and COL4A5 are redirected from the secretory pathway to autophagy. Surf4 may help deliver misfolded ER cargo, such as COL4A5 for autosomal degradation, thereby sustaining proteostasis in podocytes.

Background: Macrophages play a central role in systemic iron homeostasis by recycling iron from senescent erythrocytes through the only known cellular iron exporter, ferroportin (Fpn). Previous studies have shown that Fpn localizes to membrane microdomains, or lipid rafts, which are important for its function and regulation by hepcidin. Iron strongly promotes the enrichment of Fpn in lipid rafts. However, the proteomic composition of these domains during iron overload remains largely unexplored. Objective: This study aimed to characterize iron-induced changes in the macrophage lipid raft proteome in order to identify potential functional partners of Fpn and better define the cellular mechanisms involved in the response to iron overload. Methods: Quantitative iTRAQ-based proteomic analysis was performed on detergent-resistant membranes (DRMs) isolated by iodixanol density-gradient ultracentrifugation from J774a.1 macrophages treated with iron-NTA (FeNTA). Key proteomic observations were further validated in both J774a.1 cells and bone marrow-derived macrophages (BMDMs) using western blot, cell-surface biotinylation, and confocal immunofluorescence microscopy. The regulatory role of the transcription factor Nrf2 was also assessed using Nrf2-knockout mouse models. Results: In addition of Fpn, our lipid raft proteome identified 79 proteins significatively upregulated upon iron treatment, including, antioxidant proteins like the peroxiredoxin-1 (Prdx1), the glucose-6-phosphate dehydrogenase X-linked (G6pdx), as well as heme oxygenase-1 (Hmox1). Bioinformatic and functional analyses indicated that this response is associated with nuclear translocation of Nrf2, which is required for the transcriptional induction of Fpn and Hmox1. Whereas Fpn was detected in lipid rafts under basal conditions, Hmox1 was recruited to these domains only after iron or heme treatment. Confocal microscopy and cell-surface biotinylation assays confirmed that Hmox1 and Fpn colocalize at the plasma membrane, particularly within caveolae, specialized invaginated lipid raft domains. Conclusions: Iron or heme overload induces a major remodeling of the macrophage membrane, leading to the formation of specialized lipid raft platforms enriched in antioxidant and iron handling proteins. The coordinated localization of Hmox1 and Fpn at the cell surface suggests a coupled mechanism linking heme catabolism to iron export. This organization may help limit intracellular iron accumulation and protect the plasma membrane from iron-mediated lipid peroxidation.

Hematopoietic stem cells (HSCs) give rise to all blood cell lineages and possess long-term self-renewal potential. HSCs undergo symmetric division for their expansion and asymmetric division to generate one HSCs and one progenitor cells which contribute to production of mature blood cells. The midbody is a structure which is formed in the center of the intercellular bridge during cytokinesis. However, the midbody is either asymmetrically inherited by one daughter cell or symmetrically released after cell division, whether these distinct patterns of midbody inheritance influence HSC fate remain poorly understood. In this study, we designed a fusion protein hmKO2 and MgcRacGAP which is a component of midbody. We then traced the midbody inheritance during cell division and the future cell fates of HSC daughters after division by time-lapse imaging. As a result, we found that the midbody release correlated with the delay of the time to the next division but not to the lineage potential of HSCs, indicating the possibility that midbody remnant plays some roles in cell cycle progression. HighlightHematopoietic stem cells exhibit a low frequency of midbody inheritance. Midbody inheritance does not affect the lineage potential of daughter cells. Midbody loss is associated with delayed entry into the next cell cycle.

BACKGROUNDInterleukin-27 (IL-27) is a heterodimeric cytokine that serves as a bifunctional rheostat rather than an inherently pro- or anti-inflammatory signaling protein. However, the specific role of IL-27 in regulating systolic overload-induced cardiac inflammation and heart failure (HF) pathogenesis remains unknown. METHODSWe investigated the effects of genetic IL-27 receptor deficiency (IL-27R knockout), pharmacological IL-27 blockade, and recombinant IL-27 administration on transverse aortic constriction (TAC)-induced HF in mice. RESULTSCardiac IL-27 expression was significantly elevated in both murine and human HF tissues. The global genetic ablation of the IL-27 receptor (IL-27R) significantly suppressed TAC-induced cardiac inflammation, fibrosis, hypertrophy, HF progression, and mortality. Corroborating these protective effects, transcriptomic analysis (RNA-seq) revealed that IL-27R deficiency drastically suppressed pathways driving immune responses and antigen presentation, alongside the significant downregulation of networks governing systemic inflammation, pathogen infection, and extracellular matrix remodeling. Furthermore, pharmacological neutralization of IL-27 effectively attenuated TAC-induced left ventricular dysfunction, chamber dilation, myocardial hypertrophy, fibrosis, and leukocyte infiltration. Conversely, the administration of recombinant mouse IL-27 exacerbated the TAC-induced cardiac accumulation of multiple immune cell subsets, resulting in worsened cardiac fibrosis, cardiomyocyte hypertrophy, and overall HF progression. CONCLUSIONSOur findings demonstrate that IL-27 acts as a critical pathogenic driver of cardiac inflammation and HF development by modulating both cardiac immune cells (predominantly T cells) and non-immune cells, highlighting the IL-27 signaling axis as a promising therapeutic target.

Background: Venous thromboembolism (VTE), which encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE), is a frequent disease associated with thrombus formation and vein wall remodeling. Hence, fibrosis might result from endothelial-to-mesenchymal transition (EndMT), characterized by the loss of endothelial markers and the acquisition of mesenchymal markers. In chronic thromboembolic pulmonary hypertension, transforming growth factor (TGF{beta}), the most potent inducer of EndMT, impairs thrombus resolution. However, the molecular mechanisms implicated in TGF[beta] signaling in the context of VTE are unknown. We hypothesized that epigenetic processes regulate the TGF{beta} signaling pathway in endothelial cells promoting EndMT and vascular fibrosis. Aims: To determine if the histone deacetylase 6 (HDAC6) regulates the TGF{beta} signaling pathway in endothelial cells promoting EndMT and delays venous thrombosis. Methods: To study the role of HDAC6 in EndMT, endothelial cells were treated with a pharmacological inhibitor (TCS20b) and incubated with TGF{beta} and thrombin for 2, 3, and 5 days. Real time PCR and Western blot were performed to analyze endothelial and mesenchymal marker expression and TGF{beta} signaling. An experimental model of VTE was used to study the role of HDAC6 on thrombus size overtime. Animals were treated or not with a specific HDAC6 inhibitor (tubastatin A) for 7 to 21 days. Analysis of RNAseq data sets publicly available were used to confirm our main results. Within group and treatment differences were analyzed using two-way ANOVA and Tukeys multiple comparisons. Results: Expression of the mesenchymal markers, calponin and transgelin, was increased by TGF{beta} and thrombin. Interestingly these changes were inhibited in presence of TCS20b. TGF{beta} mediated these effects through ERK1/2 and HDAC6 activation. Inhibition of HDAC6 in vivo reduced thrombus size 7 days after surgery compared to controls. This was associated with reduced expression of the EndMT marker transgelin in endothelial cells compared to the control animals. We found that FN1-EDA expression was associated with EndMT and regulated by HDAC6 in vitro. This marker was also associated with thrombosis in the RNAseq data set that we analyzed and potentially in patients with recurrent DVT. Conclusion: We found that HDAC6 regulates EndMT in venous thrombosis and impairs thrombus resolution. HDAC6 also regulates expression FN1-EDA that appears to be a strong marker associated with DVT and DVT recurrence. Thus, HDAC6 might represent an attractive therapeutic target for patients with a high risk of recurrent VTE.

The NLRP3 D301N substitution, the murine ortholog of the human D303N variant, causes NLRP3 constitutive activation (NLRP3CA) and inflammasome assembly. Here, we show that priming signals induced by lipopolysaccharide (LPS) are sufficient to trigger GSDMD-dependent pyroptosis in NLRP3CA-expressing bone marrow-derived macrophages (BMDMs), but not in wild-type (NLRP3WT) cells. NLRP3CA mice exhibit elevated IL-1{beta} secretion and LDH release in bone marrow supernatants under both basal and LPS-challenged conditions. Other cytokines (e.g., TNF-) increased comparably between genotypes, indicating that NLRP3CA specifically amplifies inflammasome-dependent responses. Conditioned medium (CM) from LPS-treated NLRP3CA BMDMs significantly enhanced osteoclast (OC) differentiation in vivo and in vitro compared to NLRP3WT CM, as did bone marrow supernatants from NLRP3CA mice. This osteoclastogenic activity was largely independent of IL-1{beta}, as demonstrated by experiments using IL-1{beta}-deficient NLRP3CA BMDMs, IL-1{beta}-neutralizing antibodies, and genetic deletion of the IL-1 receptor. The osteoclastogenic factors were primarily soluble proteins, as heat inactivation and proteinase K digestion markedly reduced OC formation. Extracellular vesicles (EVs) from NLRP3CA CM modestly promoted OC differentiation, but EV-depleted supernatants retained full activity, indicating that the primary mediators are soluble proteins not carried within EVs. Together, these findings establish NLRP3CA as a well-controlled model for studying pyroptosis and demonstrate that pyroptotic cells release soluble proteins that drive osteoclastogenesis independently of IL-1{beta}.

BackgroundInsular damage leads to marked cardiovascular alterations and the mechanisms need to be understood. Mouse models provide unique opportunities to gain insights into pathophysiological mechanisms. Here, we evaluated the effects of rilmenidine, a centrally acting antihypertensive drug, on the cardiac functional parameters and cardiac inflammatory cell infiltration in a newly developed mice model of insular hemorrhagic stroke. MethodsC57BL/6J mice were instrumented for injection of blood or vehicle into the insular cortex (IC). Immediately after IC stroke induction, separate groups received intraperitoneal treatment with vehicle (0.9% NaCl, 0.1 mL/100 g) or rilmenidine (10 g/kg) for three days. Electrocardiogram recording,cardiac catecholamine levels and myocardial accumulation of immune cells were evaluated. ResultsMice subjected to hemorrhagic stroke exhibited higher baseline heart rate (HR) (control: 296 {+/-} 33 bpm vs. stroke: 349 {+/-} 38 bpm; P < 0.01) and prolonged QTc interval (control: 89 {+/-} 11 ms vs. stroke: 100 {+/-} 7 ms; P < 0.01). Stroke also increased cardiac norepinephrine levels (control: 9 {+/-} 4 ng/mg vs. stroke: 25 {+/-} 14 ng/mg; P < 0.05), as well as the number of myocardial CD68+ macrophages (control: 7 {+/-} 4 vs. stroke: 16 {+/-} 6 cells/field; P < 0.0001) and Ly6G+ neutrophils (control: 0.5 {+/-} 0.7 vs. stroke: 1.5 {+/-} 1 cells/field; P < 0.001). Rilmenidine treatment markedly prevented all major stroke- induced myocardial functional and inflammatory changes ConclusionsInsular hemorrhagic stroke in mice induces centrally mediated cardiac noradrenergic hyperactivation accompanied by myocardial accumulation of immune cells. These findings support the relevance of this murine model for investigating mechanisms associated with insular stroke.