IL-6/STAT3 Signaling Promotes Cardiac Dysfunction by Upregulating FUNDC1-Dependent Mitochondria-Associated Endoplasmic Reticulum Membranes Formation in Sepsis Mice

Immunization induces inflammation in the mouse heart during spaceflight

Space travel is a growing area of interest and includes initiatives such as NASA's Moon-to-Mars Mission. Reports on the cardiovascular effects of space travel reveal changes in morphology, metabolism, and function of the cardiovascular system. In this study, the cardiovascular response to immunization in space was studied in mice which were housed and immunized while on the International Space Station (ISS). Mice were immunized with tetanus toxoid combined with the adjuvant CpG (TT + CpG) and the effects of vaccination in space were studied using transcriptomics. Analysis of the mouse heart transcriptome was performed on flight control and flight-immunized mice. The results show that immunization aboard the ISS stimulates heightened inflammation in the heart via induction of the nuclear factor kappa B (NF-κB) signaling pathway to promote the release of the pro-inflammatory cytokines IFNγ, IL-17 and IL-6. Additional transcriptomic changes included alterations in the cytoskeleton and in the expression of transcripts associated with protection from oxidative stress. In summary, inflammation in the heart can occur following immunization in space. This investigation explores the impact of immune challenges on the heart and lays the groundwork for future research into additional cardiac alterations which can occur during spaceflight.

TLR4 Inhibition Attenuated LPS-Induced Proinflammatory Signaling and Cytokine Release in Mouse Hearts and Cardiomyocytes

BACKGROUND

Sepsis is associated with myocardial injury and early mortality. The innate immune receptor Toll-like receptor 4 (TLR4) can recognize pathogen-associated-molecular-patterns (PAMPs) and damage-associated molecular patterns (DAMPs); the latter are released during tissue injury. We hypothesized that TLR4 inhibition reduces proinflammatory signaling and cytokine release in: (1) LPS or Escherichia coli-treated isolated mouse heart; (2) LPS-treated mouse primary adult cardiomyocytes; and (3) the isolated heart during ischemia-reperfusion.

METHODS

Isolated C57BL/6N male mouse hearts were perfused for 120 min, with either LPS, E. coli, with and without CLI-095 (TLR4 inhibitor). Primary adult mouse cardiomyocytes were treated with LPS or LPS + CLI-095. Isolated hearts, exposed to 35 min of global ischemia, were treated with either vehicle or CLI-095 during reperfusion. Infarct size was quantified by triphenyltetrazolium staining. Cytokine expression was analyzed with ELISA, western blot analysis, and qPCR.

RESULTS

In isolated hearts, E. coli increased the expression of proinflammatory cytokines (IL-6 and CXCL2), which was not attenuated with TLR4 inhibition. TLR4 inhibition reduced expression (p = 0.004) and release of IL-6 (p < 0.0001) in LPS-exposed isolated hearts. LPS activated the nuclear-factor κ-light-chain-enhancer of activated B cells signaling pathway (NF-κB) in primary adult cardiomyocytes. Moreover, TLR4 inhibition reduced LPS-induced mRNA expression and release of IL-6 in primary adult cardiomyocytes. Isolated hearts treated with CLI-095 during reperfusion after ischemia (induced DAMPs release) showed reduced infarct size (39 ± 17% to 26 ± 8%, p = 0.034) and decreased IL-6 release (p = 0.006).

CONCLUSION

Inhibition of TLR4 reduced proinflammatory signaling and cytokine release in LPS-treated and ischemia-reperfused isolated mouse hearts and in primary adult murine cardiomyocytes.

FUNDC1 predicts Poor Prognosis and promotes Progression and Chemoresistance in Endometrial Carcinoma

Absence of effective prognostic biomarkers and therapeutic targets for reversing chemoresistance of endometrial carcinoma (EC) remains a huge challenge for clinicians. Mitophagy plays a crucial role in carcinogenesis and chemoresistance. FUN14 domain-containing protein 1 (FUNDC1) is a novel mitophagy receptor protein involved in tumorigenesis under hypoxic conditions. However, the implication of FUNDC1 in EC progression, chemoresistance in particular, remains unclear. Based on The Cancer Genome Atlas (TCGA) cohort, comprised of 403 EC patients, the association of FUNDC1 mRNA levels with hypoxia-inducible factor 1α (HIF-1α) expression, clinicopathologic features and prognosis in EC was analyzed, and subsequently verified utilizing immunohistochemistry of 288 EC specimens. Analysis of the cohort in TCGA showed that patients with higher FUNDC1 levels exhibited worse OS, with the shortest OS exhibited by patients with co-upregulated FUNDC1 and HIF-1α (P < 0.05). Analysis of the validation cohort indicated that OS and PFS rates of high-FUNDC1 patients were lower than that of low-FUNDC1 group (P < 0.05). Cases with co-downregulation of FUNDC1 and HIF-1α had higher OS and PFS rates than those with co-upregulation of these two proteins (88.8% vs. 71.2%, P = 0.002; 85.6% vs. 71.2%, P = 0.009). Higher FUNDC1 expression was observed in platinum-resistant patients. Multivariate Cox regression analysis revealed that FUNDC1 expression, FIGO stage, lymphatic invasion, depth of myometrial invasion, and ascites were independent risk factors for OS and PFS. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that FUNDC1 was closely related to spliceosome, neurodegeneration pathways of multiple diseases, and cell cycle signaling pathways. Significantly enriched RNA splicing and ncRNA processing were identified in Gene Ontology (GO) analysis. Gene set enrichment analysis (GSEA) indicated that abnormal expression of FUNDC1 was involved in endometrial cancer, NOD-like receptor signaling pathway and cytokine signaling in the immune system. In addition, immune cell infiltration analysis by Tumor Immune Estimation Resources (TIMER) database and the Xiantao academic tool demonstrated that FUNDC1 expression was strongly associated with the infiltration of Th2, NK, Th17, Tem, pDC, neutrophil, MDSC, CD4+ T, and γδ T cells. Knockdown of FUNDC1 using shRNA in HEC-1B and Ishikawa EC cells inhibited proliferation, migration and invasion, accompanied by enhanced chemotherapeutic susceptibility to carboplatin and paclitaxel. Accordingly, FUNDC1 could be a prospective prognostic biomarker and potential therapeutic target for EC.

The Specific ROCK2 Inhibitor KD025 Alleviates Glycolysis through Modulating STAT3-, CSTA- and S1PR3-Linked Signaling in Human Trabecular Meshwork Cells

To investigate the biological significance of Rho-associated coiled-coil-containing protein kinase (ROCK) 2 in the human trabecular meshwork (HTM), changes in both metabolic phenotype and gene expression patterns against a specific ROCK2 inhibitor KD025 were assessed in planar-cultured HTM cells. A seahorse real-time ATP rate assay revealed that administration of KD025 significantly suppressed glycolytic ATP production rate and increased mitochondrial ATP production rate in HTM cells. RNA sequencing analysis revealed that 380 down-regulated and 602 up-regulated differentially expressed genes (DEGs) were identified in HTM cells treated with KD025 compared with those that were untreated. Gene ontology analysis revealed that DEGs were more frequently related to the plasma membrane, extracellular components and integral cellular components among cellular components, and related to signaling receptor binding and activity and protein heterodimerization activity among molecular functions. Ingenuity Pathway Analysis (IPA) revealed that the detected DEGs were associated with basic cellular biological and physiological properties, including cellular movement, development, growth, proliferation, signaling and interaction, all of which are associated with cellular metabolism. Furthermore, the upstream regulator analysis and causal network analysis estimated IL-6, STAT3, CSTA and S1PR3 as possible regulators. Current findings herein indicate that ROCK2 mediates the IL-6/STAT3-, CSTA- and S1PR3-linked signaling related to basic biological activities such as glycolysis in HTM cells.

The structure and function of FUN14 domain-containing protein 1 and its contribution to cardioprotection by mediating mitophagy

Cardiovascular disease (CVD) is a serious public health risk, and prevention and treatment efforts are urgently needed. Effective preventive and therapeutic programs for cardiovascular disease are still lacking, as the causes of CVD are varied and may be the result of a multifactorial combination. Mitophagy is a form of cell-selective autophagy, and there is increasing evidence that mitophagy is involved in cardioprotective processes. Recently, many studies have shown that FUN14 domain-containing protein 1 (FUNDC1) levels and phosphorylation status are highly associated with many diseases, including heart disease. Here, we review the structure and functions of FUNDC1 and the path-ways of its mediated mitophagy, and show that mitophagy can be effectively activated by dephosphorylation of Ser13 and Tyr18 sites, phosphorylation of Ser17 site and ubiquitination of Lys119 site in FUNDC1. By effectively activating or inhibiting excessive mitophagy, the quality of mitochondria can be effectively controlled. The main reason is that, on the one hand, improper clearance of mitochondria and accumulation of damaged mitochondria are avoided, and on the other hand, excessive mitophagy causing apoptosis is avoided, both serving to protect the heart. In addition, we explore the possible mechanisms by which FUNDC1-mediated mitophagy is involved in exercise preconditioning (EP) for cardioprotection. Finally, we also point out unresolved issues in FUNDC1 and its mediated mitophagy and give directions where further research may be needed.

Mitochondria-associated endoplasmic reticulum membranes as a therapeutic target for cardiovascular diseases

Cardiovascular diseases (CVDs) are currently the leading cause of death worldwide. In 2022, the CVDs contributed to 19.8 million deaths globally, accounting for one-third of all global deaths. With an aging population and changing lifestyles, CVDs pose a major threat to human health. Mitochondria-associated endoplasmic reticulum membranes (MAMs) are communication platforms between cellular organelles and regulate cellular physiological functions, including apoptosis, autophagy, and programmed necrosis. Further research has shown that MAMs play a critical role in the pathogenesis of CVDs, including myocardial ischemia and reperfusion injury, heart failure, pulmonary hypertension, and coronary atherosclerosis. This suggests that MAMs could be an important therapeutic target for managing CVDs. The goal of this study is to summarize the protein complex of MAMs, discuss its role in the pathological mechanisms of CVDs in terms of its functions such as Ca2+ transport, apoptotic signaling, and lipid metabolism, and suggest the possibility of MAMs as a potential therapeutic approach.

Identification and validation of a novel glycolysis-related ceRNA network for sepsis-induced cardiomyopathy

Purpose

Sepsis-induced cardiomyopathy (SIC) is a major life-threatening condition in critically infected patients. Early diagnosis and intervention are important to improve patient prognosis. Recognizing the pivotal involvement of the glycolytic pathway in SIC, this study aims to establish a glycolysis-related ceRNA network and explore novel diagnostic avenues.

Materials and methods

SIC-related datasets were carefully filtered from the GEO database. CytoHubba was used to identify differentially expressed genes (DEGs) associated with glycolysis. A predictive method was then used to construct an lncRNA-miRNA-mRNA network. Dual-luciferase reporter assays validated gene interactions, and the specificity of this ceRNA network was confirmed in peripheral blood mononuclear cells (PBMCs) from SIC patients. Logistic analysis was used to examine the correlation between the ceRNA network and SIC. Diagnostic potential was assessed using receiver operating characteristic (ROC) curves, and correlation analysis investigated any associations between gene expression and clinical indicators.

Results

IER3 was identified as glycolysis-related DEG in SIC, and a ceRNA network (SNHG17/miR-214-3p/IER3) was established by prediction. Dual luciferase reporter gene assay confirmed the presence of mutual binding between IER3, miR-214-3p and SNHG17. RT-qPCR verified the specific expression of this ceRNA network in SIC patients. Multivariate logistic analysis established the correlation between the ceRNA network and SIC. ROC analysis demonstrated its high diagnostic specificity (AUC > 0.8). Correlation analysis revealed a negative association between IER3 expression and oxygenation index in SIC patients (p < 0.05). Furthermore, miR-214-3p expression showed a negative correlation with NT-proBNP (p < 0.05).

Conclusion

In this study, we identified and validated a ceRNA network associated with glycolysis in SIC: SNHG17/miR-214-3p/IER3. This ceRNA network may play a critical role in the onset and development of SIC. This finding is important to further our understanding of the pathophysiological mechanisms underlying SIC and to explore potential diagnostic and therapeutic targets for SIC.

Xijiao Dihuang Decoction Protects Against Murine Sepsis-Induced Cardiac Inflammation and Apoptosis via Suppressing TLR4/NF-κB and Activating PI3K/AKT Pathway

Background

Xijiao Dihuang decoction (XJDHT), a traditional Chinese medicine, is widely used to treat patients with sepsis. However, the mechanisms underlying the effects of XJDHT on cardiac dysfunction have yet to be fully elucidated. The present study evaluated the potential utility of XJDHT in protecting against sepsis-induced cardiac dysfunction and myocardial injury.

Methods

The mice were randomly divided into 3 groups and administered Lipopolysaccharide (LPS,10 mg/kg) or equivalent saline solution (control) and treated with XJDHT (10 g/kg/day) or saline by gavage for 72 hours. XJDHT was dissolved in 0.9% sodium chloride and administered at 200 μL per mouse. Transthoracic echocardiography, RNA-seq, TUNEL assays and hematoxylin and eosin (H&E) staining of cardiac tissues were performed.

Results

Treatment with XJDHT significantly enhanced myocardial function and attenuated pathological change, infiltration of inflammatory cells, levels of TNF-α, IL-1β and expression of TLR4 and NF-κB in mice with sepsis. RNA sequencing and Kyoto Encyclopedia of Genes and Genomes pathway analyses identified 531 differentially expressed genes and multiple enriched signaling pathways including the PI3K/AKT pathway. Further, XJDHT attenuated cardiac apoptosis and decreased Bax protein expression while increasing protein levels of Bcl-2, PI3K, and p-AKT in cardiac tissues of mice with sepsis.

Conclusion

In summary, XJDHT improves cardiac function in a murine model of sepsis by attenuating cardiac inflammation and apoptosis via suppressing the TLR4/NF-κB pathway and activating the PI3K/AKT pathway.

So close, yet so far away: the relationship between MAM and cardiac disease

Mitochondria-associated membrane (MAM) serve as crucial contact sites between mitochondria and the endoplasmic reticulum (ER). Recent research has highlighted the significance of MAM, which serve as a platform for various protein molecules, in processes such as calcium signaling, ATP production, mitochondrial structure and function, and autophagy. Cardiac diseases caused by any reason can lead to changes in myocardial structure and function, significantly impacting human health. Notably, MAM exhibits various regulatory effects to maintain cellular balance in several cardiac diseases conditions, such as obesity, diabetes mellitus, and cardiotoxicity. MAM proteins independently or interact with their counterparts, forming essential tethers between the ER and mitochondria in cardiomyocytes. This review provides an overview of key MAM regulators, detailing their structure and functions. Additionally, it explores the connection between MAM and various cardiac injuries, suggesting that precise genetic, pharmacological, and physical regulation of MAM may be a promising strategy for preventing and treating heart failure.

ANXA1sp attenuates sepsis-induced myocardial injury by promoting mitochondrial biosynthesis and inhibiting oxidative stress and autophagy via SIRT3 upregulation

Sepsis-induced myocardial injury is one of the most difficult complications of sepsis in intensive care units. Annexin A1 (ANXA1) short peptide (ANXA1sp) protects organs during the perioperative period. However, the protective effect of ANXA1sp against sepsis-induced myocardial injury remains unclear. We aimed to explore the protective effects and mechanisms of ANXA1sp against sepsis-induced myocardial injury both in vitro and in vivo. Cellular and animal models of myocardial injury in sepsis were established with lipopolysaccharide. The cardiac function of mice was assessed by high-frequency echocardiography. Elisa assay detected changes in inflammatory mediators and markers of myocardial injury. Western blotting detected autophagy and mitochondrial biosynthesis-related proteins. Autophagic flux changes were observed by confocal microscopy, and autophagosomes were evaluated by TEM. ATP, SOD, ROS, and MDA levels were also detected.ANXA1sp pretreatment enhanced the 7-day survival rate, improved cardiac function, and reduced TNF-α, IL-6, IL-1β, CK-MB, cTnI, and LDH levels. ANXA1sp significantly increased the expression of sirtuin-3 (SIRT3), mitochondrial biosynthesis-related proteins peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α), and mitochondrial transcription factor A (TFAM). ANXA1sp increased mitochondrial membrane potential (△Ψm), ATP, and SOD, and decreased ROS, autophagy flux, the production of autophagosomes per unit area, and MDA levels. The protective effect of ANXA1sp decreased significantly after SIRT3 silencing in vitro and in vivo, indicating that the key factor in ANXA1sp's protective role is the upregulation of SIRT3. In summary, ANXA1sp attenuated sepsis-induced myocardial injury by upregulating SIRT3 to promote mitochondrial biosynthesis and inhibit oxidative stress and autophagy.

Janus kinase inhibitors are potential therapeutics for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a poorly treated multifactorial neurodegenerative disease associated with multiple cell types and subcellular organelles. As with other multifactorial diseases, it is likely that drugs will need to target multiple disease processes and cell types to be effective. We review here the role of Janus kinase (JAK)/Signal transducer and activator of transcription (STAT) signalling in ALS, confirm the association of this signalling with fundamental ALS disease processes using the BenevolentAI Knowledge Graph, and demonstrate that inhibitors of this pathway could reduce the ALS pathophysiology in neurons, glia, muscle fibres, and blood cells. Specifically, we suggest that inhibition of the JAK enzymes by approved inhibitors known as Jakinibs could reduce STAT3 activation and modify the progress of this disease. Analysis of the Jakinibs highlights baricitinib as a suitable candidate due to its ability to penetrate the central nervous system and exert beneficial effects on the immune system. Therefore, we recommend that this drug be tested in appropriately designed clinical trials for ALS.

Rapidly Inhibiting the Inflammatory Cytokine Storms and Restoring Cellular Homeostasis to Alleviate Sepsis by Blocking Pyroptosis and Mitochondrial Apoptosis Pathways

Pyroptosis, systemic inflammation, and mitochondrial apoptosis are the three primary contributors to sepsis's multiple organ failure, the ultimate cause of high clinical mortality. Currently, the drugs under development only target a single pathogenesis, which is obviously insufficient. In this study, an acid-responsive hollow mesoporous polydopamine (HMPDA) nanocarrier that is highly capable of carrying both the hydrophilic drug NAD+ and the hydrophobic drug BAPTA-AM, with its outer layer being sealed by the inflammatory targeting peptide PEG-LSA, is developed. Once targeted to the region of inflammation, HMPDA begins depolymerization, releasing the drugs NAD+ and BAPTA-AM. Depletion of polydopamine on excessive reactive oxygen species production, promotion of ATP production and anti-inflammation by NAD+ replenishment, and chelation of BAPTA (generated by BA-AM hydrolysis) on overloaded Ca2+ can comprehensively block the three stages of sepsis, i.e., precisely inhibit the activation of pyroptosis pathway (NF-κB-NLRP3-ASC-Casp-1), inflammation pathway (IL-1β, IL-6, and TNF-α), and mitochondrial apoptosis pathway (Bcl-2/Bax-Cyt-C-Casp-9-Casp-3), thereby restoring intracellular homeostasis, saving the cells in a state of "critical survival," further reducing LPS-induced systemic inflammation, finally restoring the organ functions. In conclusion, the synthesis of this agent provides a simple and effective synergistic drug delivery nanosystem, which demonstrates significant therapeutic potential in a model of LPS-induced sepsis.

Mitochondria-endoplasmic reticulum contacts in sepsis-induced myocardial dysfunction

Mitochondrial and endoplasmic reticulum (ER) are important intracellular organelles. The sites that mitochondrial and ER are closely related in structure and function are called Mitochondria-ER contacts (MERCs). MERCs are involved in a variety of biological processes, including calcium signaling, lipid synthesis and transport, autophagy, mitochondrial dynamics, ER stress, and inflammation. Sepsis-induced myocardial dysfunction (SIMD) is a vital organ damage caused by sepsis, which is closely associated with mitochondrial and ER dysfunction. Growing evidence strongly supports the role of MERCs in the pathogenesis of SIMD. In this review, we summarize the biological functions of MERCs and the roles of MERCs proteins in SIMD.

Left ventricle- and skeletal muscle-derived fibroblasts exhibit a differential inflammatory and metabolic responsiveness to interleukin-6

Interleukin-6 (IL-6) is an important player in chronic inflammation associated with heart failure and tumor-induced cachexia. Fibroblasts are salient mediators of both inflammation and fibrosis. Whereas the general outcome of IL-6 on the heart’s function and muscle wasting has been intensively studied, the influence of IL-6 on fibroblasts of the heart and skeletal muscle (SM) has not been analyzed so far. We illustrate that SM-derived fibroblasts exhibit higher basal mRNA expression of α-SMA, extracellular matrix molecules (collagen1a1/3a1/5a1), and chemokines (CCL2, CCL7, and CX3CL1) as compared to the left ventricle (LV)-derived fibroblasts. IL-6 drives the transdifferentiation of fibroblasts into myofibroblasts as indicated by an increase in α-SMA expression and upregulates NLRP3 inflammasome activity in both LV- and SM-derived fibroblasts. IL-6 increases the release of CCL7 to CX3CL1 in the supernatant of SM-derived fibroblasts associated with the attraction of more pro(Ly6C^hi) versus anti(Ly6C^lo) inflammatory monocytes as compared to unstimulated fibroblasts. IL-6-stimulated LV-derived fibroblasts attract less Ly6C^hi to Ly6C^lo monocytes compared to IL-6-stimulated SM-derived fibroblasts. In addition, SM-derived fibroblasts have a higher mitochondrial energy turnover and lower glycolytic activity versus LV-derived fibroblasts under basal and IL-6 conditions. In conclusion, IL-6 modulates the inflammatory and metabolic phenotype of LV- and SM-originated fibroblasts.

Beneficial Effects of O-GlcNAc Stimulation in a Young Rat Model of Sepsis: Beyond Modulation of Gene Expression

The young population, which is particularly at risk of sepsis, is, paradoxically, rarely studied. Acute stimulation of O-GlcNAcylation, a post-translational modification involved in metabolic regulation, cell survival and stress response, is beneficial in young rats with sepsis. Considering that sepsis impacts the gene expression profile and that O-GlcNAcylation is a regulator of transcription, the aims of this study are to (i) unveil beneficial mechanisms of O-GlcNAcylation and (ii) decipher the relationship between O-GlcNAcylation and transcription during sepsis. Endotoxemic challenge was induced in 28-day-old male rats using a lipopolysaccharide injection (E. coli O111:B4, 20 mg·kg−1) and compared to control rats (NaCl 0.9%). One hour after, rats were assigned to no therapy or fluidotherapy (NaCl 0.9%, 10 mL.kg−1) ± NButGT (10 mg·kg−1) to stimulate O-GlcNAc levels. Cardiac O-GlcNAcylation levels were evaluated via Western blot and gene transcription using 3′ SRP analysis. Lipopolysaccharide injection favorizes inflammatory state with the overexpression of genes involved in the NF-κB, JAK/STAT and MAPK pathways. NButGT treatment increased cardiac O-GlcNAcylation levels (p < 0.05). Yet, the mRNA expression was not impacted two hours after fluidotherapy or NButGT treatment. In conclusion, O-GlcNAc stimulation-induced beneficial effects are not dependent on the gene expression profile at the early phase of sepsis.

Compositions and Functions of Mitochondria-Associated Endoplasmic Reticulum Membranes and Their Contribution to Cardioprotection by Exercise Preconditioning

Mitochondria-associated endoplasmic reticulum membranes (MAMs) are important components of intracellular signaling and contribute to the regulation of intracellular Ca²⁺/lipid homeostasis, mitochondrial dynamics, autophagy/mitophagy, apoptosis, and inflammation. Multiple studies have shown that proteins located on MAMs mediate cardioprotection. Exercise preconditioning (EP) has been shown to protect the myocardium from adverse stimuli, but these mechanisms are still being explored. Recently, a growing body of evidence points to MAMs, suggesting that exercise or EP may be involved in cardioprotection by modulating proteins on MAMs and subsequently affecting MAMs. In this review, we summarize the latest findings on MAMs, analyzing the structure and function of MAMs and the role of MAM-related proteins in cardioprotection. We focused on the possible mechanisms by which exercise or EP can modulate the involvement of MAMs in cardioprotection. We found that EP may affect MAMs by regulating changes in MFN2, MFN1, AMPK, FUNDC1, BECN1, VDAC1, GRP75, IP3R, CYPD, GSK3β, AKT, NLRP3, GRP78, and LC3, thus playing a cardioprotective role. We also provided direction for future studies that may be of interest so that more in-depth studies can be conducted to elucidate the relationship between EP and cardioprotection.

β-Elemene Attenuates Renal Fibrosis in the Unilateral Ureteral Obstruction Model by Inhibition of STAT3 and Smad3 Signaling via Suppressing MyD88 Expression

Renal fibrosis is a chronic pathological process that seriously endangers human health. However, the current therapeutic options for this disease are extremely limited. Previous studies have shown that signaling factors such as JAK2/STAT3, Smad3, and Myd88 play a regulatory role in renal fibrosis, and β-elemene is a plant-derived sesquiterpenoid organic compound that has been shown to have anti-inflammatory, anti-cancer, and immunomodulatory effects. In the present study, the anti-fibrotic effect of β-elemene was demonstrated by in vivo and in vitro experiments. It was shown that β-elemene inhibited the synthesis of extracellular matrix-related proteins in unilateral ureteral obstruction mice, and TGF-β stimulated rat interstitial fibroblast cells, including α-smooth muscle actin, vimentin, and connective tissue growth factor, etc. Further experiments showed that β-elemene reduced the expression levels of the above-mentioned fibrosis-related proteins by blocking the phosphorylation of JAK2/STAT3, Smad3, and the expression or up-regulation of MyD88. Notably, knockdown of MyD88 attenuated the phosphorylation levels of STAT3 and Smad3 in TGF-β stimulated NRK49F cell, which may be a novel molecular mechanism by which β-elemene affects renal interstitial fibrosis. In conclusion, this study elucidated the anti-interstitial fibrosis effect of β-elemene, which provides a new direction for future research and development of drugs related to chronic kidney disease.

Myocardial protection of S-nitroso-L-cysteine in diabetic cardiomyopathy mice

Diabetic cardiomyopathy (DCM) is a severe complication of diabetes mellitus that is characterized by aberrant myocardial structure and function and is the primary cause of heart failure and death in diabetic patients. Endothelial dysfunction plays an essential role in diabetes and is associated with an increased risk of cardiovascular events, but its role in DCM is unclear. Previously, we showed that S-nitroso-L-cysteine(CSNO), an endogenous S-nitrosothiol derived from eNOS, inhibited the activity of protein tyrosine phosphatase 1B (PTP1B), a critical negative modulator of insulin signaling. In this study, we reported that CSNO treatment induced cellular insulin-dependent and insulin-independent glucose uptake. In addition, CSNO activated insulin signaling pathway and promoted GLUT4 membrane translocation. CSNO protected cardiomyocytes against high glucose-induced injury by ameliorating excessive autophagy activation, mitochondrial impairment and oxidative stress. Furthermore, nebulized CSNO improved cardiac function and myocardial fibrosis in diabetic mice. These results suggested a potential site for endothelial modulation of insulin sensitivity and energy metabolism in the development of DCM. Data from these studies will not only help us understand the mechanisms of DCM, but also provide new therapeutic options for treatment.

Endothelial Dysfunction and Diabetic Cardiomyopathy

The cardiovascular complications contribute to a majority of diabetes associated morbidity and mortality, accounting for 44% of death in those patients with type 1 diabetes mellitus (DM) and 52% of deaths in type 2 DM. Diabetes elicits cardiovascular dysfunction through 2 major mechanisms: ischemic and non-ischemic. Non-ischemic injury is usually under-recognized although common in DM patients, and also a pathogenic factor of heart failure in those diabetic individuals complicated with ischemic heart disease. Diabetic cardiomyopathy (DCM) is defined as a heart disease in which the myocardium is structurally and functionally abnormal in the absence of coronary artery disease, hypertensive, valvular, or congenital heart disorders in diabetic patients, theoretically caused by non-ischemic injury solely. Current therapeutic strategies targeting DCM mainly address the increased blood glucose levels, however, the effects on heart function are disappointed. Accumulating data indicate endothelial dysfunction plays a critical role in the initiation and development of DCM. Hyperglycemia, hyperinsulinemia, and insulin resistance cause the damages of endothelial function, including barrier dysfunction, impaired nitric oxide (NO) activity, excessive reactive oxygen species (ROS) production, oxidative stress, and inflammatory dysregulation. In turn, endothelial dysfunction promotes impaired myocardial metabolism, intracellular Ca²⁺ mishandling, endoplasmic reticulum (ER) stress, mitochondrial defect, accumulation of advanced glycation end products, and extracellular matrix (ECM) deposit, leads to cardiac stiffness, fibrosis, and remodeling, eventually results in cardiac diastolic dysfunction, systolic dysfunction, and heart failure. While endothelial dysfunction is closely related to cardiac dysfunction and heart failure seen in DCM, clinical strategies for restoring endothelial function are still missing. This review summarizes the timely findings related to the effects of endothelial dysfunction on the disorder of myocardium as well as cardiac function, provides mechanical insights in pathogenesis and pathophysiology of DCM developing, and highlights potential therapeutic targets.