MG53 suppresses NFκB activation to mitigate age-related heart failure

Branched-chain amino acids and L-alanine supplementation ameliorate calcium dyshomeostasis in sarcopenia: New insights for nutritional interventions

Introduction: During aging, sarcopenia and decline in physiological processes lead to partial loss of muscle strength, atrophy, and increased fatigability. Muscle changes may be related to a reduced intake of essential amino acids playing a role in proteostasis. We have recently shown that branched-chain amino acid (BCAA) supplements improve atrophy and weakness in models of muscle disuse and aging. Considering the key roles that the alteration of Ca2+-related homeostasis and store-operated calcium entry (SOCE) play in several muscle dysfunctions, this study has been aimed at gaining insight into the potential ability of BCAA-based dietary formulations in aged mice on various players of Ca2+ dyshomeostasis. Methods: Seventeen-month-old male C57BL/6J mice received a 12-week supplementation with BCAAs alone or boosted with two equivalents of L-alanine (2-Ala) or with dipeptide L-alanyl-L-alanine (Di-Ala) in drinking water. Outcomes were evaluated on ex vivo skeletal muscles indices vs. adult 3-month-old male C57BL/6J mice. Results: Ca2+ imaging confirmed a decrease in SOCE and an increase of resting Ca2+ concentration in aged vs. adult mice without alteration in the canonical components of SOCE. Aged muscles vs. adult muscles were characterized by a decrease in the expression of ryanodine receptor 1 (RyR1), the Sarco-Endoplasmic Reticulum Calcium ATPase (SERCA) pump, and sarcalumenin together with an alteration of the expression of mitsugumin 29 and mitsugumin 53, two recently recognized players in the SOCE mechanism. BCAAs, particularly the formulation BCAAs+2-Ala, were able to ameliorate all these alterations. Discussion: These results provide evidence that Ca2+ homeostasis dysfunction plays a role in the functional deficit observed in aged muscle and supports the interest of dietary BCAA supplementation in counteracting sarcopenia-related SOCE dysregulation.

MG53 protects against Coxsackievirus B3-induced acute viral myocarditis in mice by inhibiting NLRP3 inflammasome-mediated pyroptosis via the NF-κB signaling pathway

Pyroptosis, a novel programmed cell death mediated by NOD-like receptor protein 3 (NLRP3) inflammasome, is a critical pathogenic process in acute viral myocarditis (AVMC). Mitsugumin 53 (MG53) is predominantly expressed in myocardial tissues and has been reported to exert cardioprotective effects through multiple pathways. Herein, we aimed to investigate the biological function of MG53 in AVMC and its underlying regulatory mechanism in pyroptosis. BALB/c mice and HL-1 cells were infected with Coxsackievirus B3 (CVB3) to establish animal and cellular models of AVMC. As inflammation progressed in the myocardium, we found a progressive decrease in myocardial MG53 expression, accompanied by a significant enhancement of cardiomyocyte pyroptosis. MG53 overexpression significantly alleviated myocardial inflammation, apoptosis, fibrosis, and mitochondrial damage, thereby improving cardiac dysfunction in AVMC mice. Moreover, MG53 overexpression inhibited NLRP3 inflammasome-mediated pyroptosis, reduced pro-inflammatory cytokines (IL-1β/18) release, and suppressed NF-κB signaling pathway activation both in vivo and in vitro. Conversely, MG53 knockdown reduced cell viability, facilitated cell pyroptosis, and increased pro-inflammatory cytokines release in CVB3-infected HL-1 cells by promoting NF-κB activation. These effects were partially reversed by applying the NF-κB inhibitor BAY 11-7082. In conclusion, our results suggest that MG53 acts as a negative regulator of NLRP3 inflammasome-mediated pyroptosis in CVB3-induced AVMC, partially by inhibiting the NF-κB signaling pathway. MG53 is a promising candidate for clinical applications in AVMC treatment.

MG53/TRIM72: multi-organ repair protein and beyond

MG53, a member of the tripartite motif protein family, possesses multiple functionalities due to its classic membrane repair function, anti-inflammatory ability, and E3 ubiquitin ligase properties. Initially recognized for its crucial role in membrane repair, the therapeutic potential of MG53 has been extensively explored in various diseases including muscle injury, myocardial damage, acute lung injury, and acute kidney injury. However, further research has revealed that the E3 ubiquitin ligase characteristics of MG53 also contribute to the pathogenesis of certain conditions such as diabetic cardiomyopathy, insulin resistance, and metabolic syndrome. Moreover, recent studies have highlighted the anti-tumor effects of MG53 in different types of cancer, such as small cell lung cancer, liver cancer, and colorectal cancer; these effects are closely associated with their E3 ubiquitin ligase activities. In summary, MG53 is a multifunctional protein that participates in important physiological and pathological processes of multiple organs and is a promising therapeutic target for various human diseases. MG53 plays a multi-organ protective role due to its membrane repair function and its exertion of anti-tumor effects due to its E3 ubiquitin ligase properties. In addition, the controversial aspect of MG53's E3 ubiquitin ligase properties potentially causing insulin resistance and metabolic syndrome necessitates further cross-validation for clarity.

Ubiquitin-specific protease 38 promotes inflammatory atrial fibrillation induced by pressure overload

AIMS

Atrial structural and electrical remodelling is a major reason for the initiation and perpetuation of atrial fibrillation (AF). Ubiquitin-specific protease 38 (USP38) is a deubiquitinating enzyme, but its function in the heart remains unknown. The aim of this study was to investigate the effect of USP38 in pressure overload-induced AF.

METHODS AND RESULTS

Cardiac-specific knockout USP38 and cardiac-specific transgenic USP38 mice and their corresponding control mice were used in this study. After 4 weeks with or without aortic banding (AB) surgery, atrial echocardiography, atrial histology, electrophysiological study, and molecular analysis were assessed. Ubiquitin-specific protease 38 knockout mice showed a remarkable improvement in vulnerability to AF, atrial weight and diameter, atrial fibrosis, and calcium-handling protein expression after AB surgery. Conversely, USP38 overexpression further increased susceptibility to AF by exacerbating atrial structural and electrical remodelling. Mechanistically, USP38 interacted with and deubiquitinated nuclear factor-kappa B (NF-κB), and USP38 overexpression increased the level of p-NF-κB in vivo and in vitro, accompanied by the upregulation of NOD-like receptor protein 3 (NLRP3) and inflammatory cytokines, suggesting that USP38 contributes to adverse effects by driving NF-κB/NLRP3-mediated inflammatory responses.

CONCLUSION

Overall, our study indicates that USP38 promotes pressure overload-induced AF through targeting NF-κB/NLRP3-mediated inflammatory responses.

Advances in the Study of MG53 in Cardiovascular Disease

Cardiovascular diseases represent a global health crisis, and understanding the intricate molecular mechanisms underlying cardiac pathology is crucial for developing effective diagnostic and therapeutic strategies. Mitsugumin-53 (MG53) plays a pivotal role in cell membrane repair, has emerged as a multifaceted player in cardiovascular health. MG53, also known as TRIM72, is primarily expressed in cardiac and skeletal muscle and actively participates in membrane repair processes essential for maintaining cardiomyocyte viability. It promotes k-ion currents, ensuring action potential integrity, and actively engages in repairing myocardial and mitochondrial membranes, preserving cardiac function in the face of oxidative stress. This study discusses the dual impact of MG53 on cardiac health, highlighting its cardioprotective role during ischemia/reperfusion injury, its modulation of cardiac arrhythmias, and its influence on cardiomyopathy. MG53's regulation of metabolic pathways, such as lipid metabolism, underlines its role in diabetic cardiomyopathy, while its potential to mitigate the effects of various cardiac disorders, including those induced by antipsychotic medications and alcohol consumption, warrants further exploration. Furthermore, we examine MG53's diagnostic potential as a biomarker for cardiac injury. Research has shown that MG53 levels correlate with cardiomyocyte damage and may predict major adverse cardiovascular events, highlighting its value as a biomarker. Additionally, exogenous recombinant human MG53 (rhMG53) emerges as a promising therapeutic option, demonstrating its ability to reduce infarct size, inhibit apoptosis, and attenuate fibrotic responses. In summary, MG53's diagnostic and therapeutic potential in cardiovascular diseases presents an exciting avenue for improved patient care and outcomes.

System pharmacology-based determination of the functional components and mechanisms in chronic heart failure treatment: an example of Zhenwu decoction

Chronic heart failure (CHF) is the primary cause of death among patients with cardiovascular diseases, representing the advanced stage in the development of several cardiovascular conditions. Zhenwu decoction (ZWD) has gained widespread recognition as an efficacious remedy for CHF due to its potent therapeutic properties and absence of adverse effects. Nevertheless, the precise molecular mechanisms underlying its actions remain elusive. This study endeavors to unravel the intricate pharmacological underpinnings of five herbs within ZWD concerning CHF through an integrated approach. Initially, pertinent data regarding ZWD and CHF were compiled from established databases, forming the foundation for constructing an intricate network of active component-target interactions. Subsequently, a pioneering method for evaluating node significance was formulated, culminating in the creation of core functional association space (CFAS). To discern vital components, a novel dynamic programming algorithm was devised and used to determine the core component group (CCG) within the CFAS. Enrichment analysis of the CCG targets unveiled the potential coordinated molecular mechanisms of ZWD, illuminating its capacity to ameliorate CHF by modulating genes and related signaling pathways involved in pathological remodeling. Notable pathways encompass PI3K-Akt, diabetic cardiomyopathy, cAMP and MAPK signaling. Concluding the computational analyses, in vitro experiments were executed to assess the effects of vanillic acid, paradol, 10-gingerol and methyl cinnamate. Remarkably, these compounds demonstrated efficacy in reducing the production of ANP and BNP within isoprenaline-induced AC 16 cells, further validating their potential therapeutic utility. This investigation underscores the efficacy of the proposed model in enhancing the precision and reliability of CCG selection within ZWD, thereby presenting a novel avenue for mechanistic inquiries, compound refinement and the secondary development of TCM herbs.

Causality between heart failure and epigenetic age: a bidirectional Mendelian randomization study

AIMS

Heart failure (HF) is a prevalent age-related cardiovascular disease with poor prognosis in the elderly population. This study aimed to establish the causal relationship between ageing and HF by conducting a bidirectional Mendelian randomization (MR) analysis on epigenetic age (a marker of ageing) and HF.

METHODS AND RESULTS

Genome-wide association study data for epigenetic age (GrimAge, HorvathAge, HannumAge, and PhenoAge) and HF were collected and assessed for significant genetic variables. A bidirectional MR analysis was carried out using the random-effects inverse-variance weighted (IVW) method as the primary approach, while other methods (MR-Egger, weighted median, simple mode, and weighted mode) and multiple sensitivity analyses (heterogeneity analysis, leave-one-out sensitivity analysis, and horizontal pleiotropy analysis) were employed to evaluate the impact of epigenetic age on HF and vice versa. Bidirectional MR analysis of two samples revealed that the epigenetic PhenoAge clock increased the risk of HF [IVW odds ratio (OR) 1.015, 95% confidence interval (CI) 1.002-1.028, P = 0.028 and weighted median OR 1.020, 95% CI 1.001-1.038, P = 0.039]. Other results were not statistically significant.

CONCLUSIONS

The bidirectional MR analysis demonstrated a causal link between genetically predicted epigenetic age and HF in individuals of European descent. Further research into epigenetic age in other populations and additional genetic information related to HF is warranted.

MG53 does not mark cardiovascular risk and all-cause mortality in subjects with type 2 diabetes: A prospective, observational study

AIMS

Subjects with type 2 diabetes (T2D) are characterized by a high cardiovascular morbidity and mortality. MG53, a marker of peripheral insulin resistance, has been linked with impaired β-cell function and decreased β-cell survival, and its circulating levels are increased in T2D. Its relationship with the cardiovascular risk profile and mortality in T2D is currently unknown.

METHODS

In this longitudinal study, MG53 was measured in serum samples collected at baseline for 296 Caucasian participants in the MIND.IT study, relating its circulating levels with the cardiovascular risk profile and all-cause mortality over a 17-years follow up.

RESULTS

As compared to a reference cohort of 234 healthy subjects, MG53 levels were higher in T2D individuals (p < 0.001), and higher in T2D women than in men (p = 0.001). In the whole study cohort, MG53 levels were directly related to HbA1c (r2 0.029; p = 0.006) and systolic blood pressure (r2 0.032; p = 0.004). There was no difference in baseline MG53 levels between deceased and alive participants, neither predict all-cause mortality.

CONCLUSIONS

MG53 does not mark the cardiovascular risk profile neither predict long-term mortality in Caucasian T2D individuals.

Sepsis associated with acute lung injury over the period 2012-2021: a bibliometric analysis

Background: Sepsis associated with acute lung injury (ALI) is a common acute and severe disease with severe socioeconomic burden. The aim of this study is to explore the literatures of sepsis associated with ALI from a bibliometric perspective. Methods: Articles and reviews related to sepsis associated with ALI published from 2012 to 2021 in the Web of Science Core Collection were retrieved. Countries, affiliations, journals, authors, references, co-citation and keyword analysis in this field were visually analyzed using WOS citation reports, bibliometric.com, CtieSpace and VOSviewer software. Results: Over the last decade (2012-2021), marked progress has been made in the area of sepsis associated with ALI research. 836 papers were enrolled in this study. China accounts for the most contributors. Articles from the United States has the highest average cited. Shanghai Jiao Tong University, University of California System and Huazhong University of Science Technology were the main contributing institutions. Articles in International Immunopharmacology, Inflammation, Shock and Critical Care were cited the most. Matthay MA and Ware LB were the main contributors to this field. Inflammation and NF-κB have always been the focus of sepsis associated with ALI related research, and programmed cell death (including apoptosis, necroptosis and pyroptosis) may be the important direction of future research. Conclusion: Research on the sepsis associated with ALI is flourishing. The research on programmed cell death is a hot spot and may be a promising research field in the coming years.

Potentilla anserina polysaccharide alleviates cadmium-induced oxidative stress and apoptosis of H9c2 cells by regulating the MG53-mediated RISK pathway

Oxidative stress plays a crucial role in cadmium (Cd)-induced myocardial injury. Mitsugumin 53 (MG53) and its mediated reperfusion injury salvage kinase (RISK) pathway have been demonstrated to be closely related to myocardial oxidative damage. Potentilla anserina L. polysaccharide (PAP) is a polysaccharide with antioxidant capacity, which exerts protective effect on Cd-induced damage. However, it remains unknown whether PAP can prevent and treat Cd-induced cardiomyocyte damages. The present study was desgined to explore the effect of PAP on Cd-induced damage in H9c2 cells based on MG53 and the mediated RISK pathway. For in vitro evaluation, cell viability and apoptosis rate were analyzed by CCK-8 assay and flow cytometry, respectively. Furthermore, oxidative stress was assessed by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining and using superoxide dismutase (SOD), catalase (CAT), and glutathione/oxidized glutathione (GSH/GSSG) kits. The mitochondrial function was measured by JC-10 staining and ATP detection assay. Western blot was performed to detect the expression of proteins related to MG53, the RISK pathway, and apoptosis. The results indicated that Cd increased the levels of reactive oxygen species (ROS) in H9c2 cells. Cd decreased the activities of SOD and CAT and the ratio of GSH/GSSG, resulting in decreases in cell viability and increases in apoptosis. Interestingly, PAP reversed Cd-induced oxidative stress and cell apoptosis. Meanwhile, Cd reduced the expression of MG53 in H9c2 cells and inhibited the RISK pathway, which was mediated by decreasing the ratio of p-Akt^Ser473/Akt, p-GSK3β^Ser9/GSK3β and p-ERK1/2/ERK1/2. In addition, Cd impaired mitochondrial function, which involved a reduction in ATP content and mitochondrial membrane potential (MMP), and an increase in the ratio of Bax/Bcl-2, cytoplasmic cytochrome c/mitochondrial cytochrome c, and Cleaved-Caspase 3/Pro-Caspase 3. Importantly, PAP alleviated Cd-induced MG53 reduction, activated the RISK pathway, and reduced mitochondrial damage. Interestingly, knockdown of MG53 or inhibition of the RISK pathway attenuated the protective effect of PAP in Cd-induced H9c2 cells. In sum, PAP reduces Cd-induced damage in H9c2 cells, which is mediated by increasing MG53 expression and activating the RISK pathway.

TRIM72 Alleviates Muscle Inflammation in mdx Mice via Promoting Mitophagy-Mediated NLRP3 Inflammasome Inactivation

Chronic muscle inflammation exacerbates the pathogenesis of Duchenne muscular dystrophy (DMD), which is characterized by progressive muscle degeneration and weakness. NLRP3 (nucleotide-binding domain and leucine-rich repeat pyrin domain containing 3) inflammasome plays a key role in the inflammatory process, and its abnormal activation leads to a variety of inflammatory or immune diseases. TRIM72 (MG53) is a protective myokine for tissue repair and regeneration. However, little is known about the potential impact of TRIM72 in the crosstalk between mitophagy and inflammatory process of DMD. Here, 10-week-old male mdx mice were injected intramuscularly with adeno-associated virus (AAV-TRIM72) to overexpress TRIM72 protein for 6 weeks. Then, skeletal muscle samples were collected, and relevant parameters were measured by histopathological analysis and molecular biology techniques. C2C12 cell line was transfected with lentivirus (LV-TRIM72) to overexpress or siRNA (si-TRIM72) to suppress the TRIM72 expression for the following experiment. Our data firstly showed that the TRIM72 expression was decreased in skeletal muscles of mdx mice. Then, we observed the increased NLRP3 inflammasome and impaired mitophagy in mdx mice compared with wild type mice. In mdx mice, administration of AAV-TRIM72 alleviated the accumulation of NLRP3 inflammasome and the consequent IL-18 and IL1β maturation by inducing autophagy, while this protective effect was reversed by chloroquine. Mitochondrial reactive oxygen species (mtROS), as a recognized activator for NLRP3 inflammasome, was attenuated by TRIM72 through the induction of mitophagy in C2C12 cells. Additionally, we proposed that the TRIM72 overexpression might promote mitophagy through both the early stage by PI3K-AKT pathway and the late stage by autolysosome fusion. In conclusion, the current study suggests that TRIM72 prevents DMD inflammation via decreasing NLRP3 inflammasomes and enhancing mitophagy. Collectively, our study provides insight into TRIM72 as a promising target for therapeutic intervention for DMD.

Hypothalamic Hnscr regulates glucose balance by mediating central inflammation and insulin signal

OBJECTIVES

Hypothalamic dysfunction leads to glucose metabolic imbalance; however, the mechanisms still need clarification. Our current study was to explore the role of hypothalamic Hnscr in glucose metabolism.

MATERIALS AND METHODS

Using Hnscr knockout or htNSC-specific Hnscr overexpression mice, we evaluated the effects of Hnscr on glucose metabolism through GTTs, ITTs, serum indicator measurements, etc. Immunofluorescence staining and Western blotting were performed to test inflammation levels and insulin signalling in hypothalamus. Conditioned medium intervene were used to investigate the effects of htNSCs on neuronal cell line. We also detected the glucose metabolism of mice with htNSCs implantation.

RESULTS

Hnscr expression decreased in the hypothalamus after high-fat diet feed. Hnscr-null mice displayed aggravated systematic insulin resistance, while mice with htNSC-specific Hnscr overexpression had the opposite phenotype. Notably, Hnscr-null mice had increased NF-κB signal in htNSCs, along with enhanced inflammation and damaged insulin signal in neurons located in arcuate nucleus of hypothalamus. The secretions, including sEVs, of Hnscr-deficient htNSCs mediated the detrimental effects on the CNS cell line. Locally implantation with Hnscr-depleted htNSCs disrupted glucose homeostasis.

CONCLUSIONS

This study demonstrated that decreased Hnscr in htNSCs led to systematic glucose imbalance through activating NF-κB signal and dampening insulin signal in hypothalamic neurons.

Deficient Sarcolemma Repair in ALS: A Novel Mechanism with Therapeutic Potential

The plasma membrane (sarcolemma) of skeletal muscle myofibers is susceptible to injury caused by physical and chemical stresses during normal daily movement and/or under disease conditions. These acute plasma membrane disruptions are normally compensated by an intrinsic membrane resealing process involving interactions of multiple intracellular proteins including dysferlin, annexin, caveolin, and Mitsugumin 53 (MG53)/TRIM72. There is new evidence for compromised muscle sarcolemma repair mechanisms in Amyotrophic Lateral Sclerosis (ALS). Mitochondrial dysfunction in proximity to neuromuscular junctions (NMJs) increases oxidative stress, triggering MG53 aggregation and loss of its function. Compromised membrane repair further worsens sarcolemma fragility and amplifies oxidative stress in a vicious cycle. This article is to review existing literature supporting the concept that ALS is a disease of oxidative-stress induced disruption of muscle membrane repair that compromise the integrity of the NMJs and hence augmenting muscle membrane repair mechanisms could represent a viable therapeutic strategy for ALS.

MG53 protein rejuvenates hUC-MSCs and facilitates their therapeutic effects in AD mice by activating Nrf2 signaling pathway

Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) transplantation is a promising therapy for Alzheimer's disease (AD). However, hUC-MSCs cultured in vitro easily exhibit replicative senescence, which restricts their application. Although MG53 protein demonstrates multiple roles for a variety of cells and tissues repair, it remains unknown whether MG53 could rejuvenate senescent hUC-MSCs and enhance their efficacy in AD model. Here, we firstly presented that MG53 reinstated senescent hUC-MSCs via the activation of the Nrf2 signaling pathway by increasing cell proliferation and migration, ameliorating senescence and oxidative stress, and decreasing the release of senescence-associated secretory phenotype. In vivo studies showed that MG53 treatment improved the therapeutic effect of senescent hUC-MSCs in AD mice. Furthermore, MG53 combined with young hUC-MSCs transplantation alleviated cognitive deficit and depression-like behavior in AD mice, reduced Aβ deposition and Tau phosphorylation, promoted neurogenesis, and inhibited glia cells activation and oxidative stress by activating the Nrf2 signaling. Moreover, these neuroprotective effects mediated by MG53 and hUC-MSCs were partly reversed by Brusatol, a specific inhibitor of Nrf2 signaling. Taken together, our study revealed that MG53 could rejuvenate senescent hUC-MSCs and facilitate their efficacy in AD mice at least partly through activating Nrf2 signaling pathway, which suggest that the combined therapy of MG53 and hUC-MSCs may be a novel and effective strategy for AD.

Reduced Sarcolemmal Membrane Repair Exacerbates Striated Muscle Pathology in a Mouse Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a common X-linked degenerative muscle disorder that involves mutations in the DMD gene that frequently reduce the expression of the dystrophin protein, compromising the structural integrity of the sarcolemmal membrane and leaving it vulnerable to injury during cycles of muscle contraction and relaxation. This results in an increased frequency of sarcolemma disruptions that can compromise the barrier function of the membrane and lead to death of the myocyte. Sarcolemmal membrane repair processes can potentially compensate for increased membrane disruptions in DMD myocytes. Previous studies demonstrated that TRIM72, a muscle-enriched tripartite motif (TRIM) family protein also known as mitsugumin 53 (MG53), is a component of the cell membrane repair machinery in striated muscle. To test the importance of membrane repair in striated muscle in compensating for the membrane fragility in DMD, we crossed TRIM72/MG53 knockout mice into the mdx mouse model of DMD. These double knockout (DKO) mice showed compromised sarcolemmal membrane integrity compared to mdx mice, as measured by immunoglobulin G staining and ex vivo muscle laser microscopy wounding assays. We also found a significant decrease in muscle ex vivo contractile function as compared to mdx mice at both 6 weeks and 1.5 years of age. As the DKO mice aged, they developed more extensive fibrosis in skeletal muscles compared to mdx. Our findings indicate that TRIM72/MG53-mediated membrane repair can partially compensate for the sarcolemmal fragility associated with DMD and that the loss of membrane repair results in increased pathology in the DKO mice.

Early Protective Role of Inflammation in Cardiac Remodeling and Heart Failure: Focus on TNFα and Resident Macrophages

Cardiac hypertrophy, initiated by a variety of physiological or pathological stimuli (hemodynamic or hormonal stimulation or infarction), is a critical early adaptive compensatory response of the heart. The structural basis of the progression from compensated hypertrophy to pathological hypertrophy and heart failure is still largely unknown. In most cases, early activation of an inflammatory program reflects a reparative or protective response to other primary injurious processes. Later on, regardless of the underlying etiology, heart failure is always associated with both local and systemic activation of inflammatory signaling cascades. Cardiac macrophages are nodal regulators of inflammation. Resident macrophages mostly attenuate cardiac injury by secreting cytoprotective factors (cytokines, chemokines, and growth factors), scavenging damaged cells or mitochondrial debris, and regulating cardiac conduction, angiogenesis, lymphangiogenesis, and fibrosis. In contrast, excessive recruitment of monocyte-derived inflammatory macrophages largely contributes to the transition to heart failure. The current review examines the ambivalent role of inflammation (mainly TNFα-related) and cardiac macrophages (Mφ) in pathophysiologies from non-infarction origin, focusing on the protective signaling processes. Our objective is to illustrate how harnessing this knowledge could pave the way for innovative therapeutics in patients with heart failure.

The cell membrane repair protein MG53 modulates transcription factor NF-κB signaling to control kidney fibrosis

Kidney fibrosis is associated with the progression of acute kidney injury to chronic kidney disease. MG53, a cell membrane repair protein, has been shown to protect against injury to kidney epithelial cells and acute kidney injury. Here, we evaluated the role of MG53 in modulation of kidney fibrosis in aging mice and in mice with unilateral ureteral obstruction (UUO) a known model of progressive kidney fibrosis. Mice with ablation of MG53 developed more interstitial fibrosis with age than MG53-intact mice of the same age. Similarly, in the absence of MG53, kidney fibrosis was exaggerated compared to mice with intact MG53 in the obstructed kidney compared to the contralateral unobstructed kidney or the kidneys of sham operated mice. The ureteral obstructed kidneys from MG53 deficient mice also showed significantly more inflammation than ureteral obstructed kidneys from MG53 intact mice. In vitro experiments demonstrated that MG53 could enter the nuclei of proximal tubular epithelial cells and directly interact with the p65 component of transcription factor NF-κB, providing a possible explanation of enhanced inflammation in the absence of MG53. To test this, enhanced MG53 expression through engineered cells or direct recombinant protein delivery was given to mice subject to UUO. This reduced NF-κB activation and inflammation and attenuated kidney fibrosis. Thus, MG53 may have a therapeutic role in treating chronic kidney inflammation and thereby provide protection against fibrosis that leads to the chronic kidney disease phenotype.