Targeting HMGB1 by ethyl pyruvate ameliorates systemic lupus erythematosus and reverses the senescent phenotype of bone marrow-mesenchymal stem cells

Overexpression of miR-20a-5p in mesenchymal stem cell derived-exosomes from systemic lupus erythematosus patients restored therapeutic effect and Treg immune regulation

We and other groups have documented that bone marrow-mesenchymal stem cells (BM-MSCs) from Systemic lupus erythematosus (SLE) patients demonstrated signs of senescence, including reduced ability of regulating Treg. Treg cell defects or Treg cell deficiency are regarded as significant factors in the progression of SLE. Exosomes, nanoscale vesicles, abound in molecular and genetic contents, play a critical role in intercellular communications. The purpose of this research is to investigate the mechanism of MSCs-exosomes regulating Tregs cells in SLE, further elucidate the mechanism of immune dysregulation of aging BM-MSCs, and provide theoretical basis and data support for new targets of SLE treatment. In the study, BM-MSCs and exosomes were isolated successfully. Exosomes could be up-taken by naïve CD4+T cells. MSCs-exosomes attenuated SLE clinical manifestation in vivo, but MSCs-exosomes from SLE patients were ineffective. MSCs-exosomes from SLE patients dysregulated Treg cells differentiation in vivo and in vitro. Exosomal miR-20a-5p contributed to the effect of MSCs-exosomes regulating Treg cells. Up-regulating the expression of miR-20a-5p in SLE MSCs-exosomes can restore their ability to promote Treg differentiation and treatment effect. This study further elucidated the role of in the immunomodulatory mechanism of BM-MSCs-exosomes and provided new ideas for the non-cellular autologous transplantation therapy of SLE.

A Mesenchymal stem cell Aging Framework, from Mechanisms to Strategies

Mesenchymal stem cells (MSCs) are extensively researched for therapeutic applications in tissue engineering and show significant potential for clinical use. Intrinsic or extrinsic factors causing senescence may lead to reduced proliferation, aberrant differentiation, weakened immunoregulation, and increased inflammation, ultimately limiting the potential of MSCs. It is crucial to comprehend the molecular pathways and internal processes responsible for the decline in MSC function due to senescence in order to devise innovative approaches for rejuvenating senescent MSCs and enhancing MSC treatment. We investigate the main molecular processes involved in senescence, aiming to provide a thorough understanding of senescence-related issues in MSCs. Additionally, we analyze the most recent advancements in cutting-edge approaches to combat MSC senescence based on current research. We are curious whether the aging process of stem cells results in a permanent "memory" and if cellular reprogramming may potentially revert the aging epigenome to a more youthful state.

Cellular microenvironment: a key for tuning mesenchymal stem cell senescence

Mesenchymal stem cells (MSCs) possess the ability to self-renew and differentiate into multiple cell types, making them highly suitable for use as seed cells in tissue engineering. These can be derived from various sources and have been found to play crucial roles in several physiological processes, such as tissue repair, immune regulation, and intercellular communication. However, the limited capacity for cell proliferation and the secretion of senescence-associated secreted phenotypes (SASPs) pose challenges for the clinical application of MSCs. In this review, we provide a comprehensive summary of the senescence characteristics of MSCs and examine the different features of cellular microenvironments studied thus far. Additionally, we discuss the mechanisms by which cellular microenvironments regulate the senescence process of MSCs, offering insights into preserving their functionality and enhancing their effectiveness.

HMGB1 and Toll-like receptors: potential therapeutic targets in autoimmune diseases

HMGB1, a nucleoprotein, is expressed in almost all eukaryotic cells. During cell activation and cell death, HMGB1 can function as an alarm protein (alarmin) or damage-associated molecular pattern (DAMP) and mediate early inflammatory and immune response when it is translocated to the extracellular space. The binding of extracellular HMGB1 to Toll-like receptors (TLRs), such as TLR2 and TLR4 transforms HMGB1 into a pro-inflammatory cytokine, contributing to the occurrence and development of autoimmune diseases. TLRs, which are members of a family of pattern recognition receptors, can bind to endogenous DAMPs and activate the innate immune response. Additionally, TLRs are key signaling molecules mediating the immune response and play a critical role in the host defense against pathogens and the maintenance of immune balance. HMGB1 and TLRs are reported to be upregulated in several autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, type 1 diabetes mellitus, and autoimmune thyroid disease. The expression levels of HMGB1 and some TLRs are upregulated in tissues of patients with autoimmune diseases and animal models of autoimmune diseases. The suppression of HMGB1 and TLRs inhibits the progression of inflammation in animal models. Thus, HMGB1 and TLRs are indispensable biomarkers and important therapeutic targets for autoimmune diseases. This review provides comprehensive strategies for treating or preventing autoimmune diseases discovered in recent years.

High Mobility Group Box 1 (HMGB1): Potential Target in Sepsis-Associated Encephalopathy

Sepsis-associated encephalopathy (SAE) remains a challenge for intensivists that is exacerbated by lack of an effective diagnostic tool and an unambiguous definition to properly identify SAE patients. Risk factors for SAE development include age, genetic factors as well as pre-existing neuropsychiatric conditions. Sepsis due to certain infection sites/origins might be more prone to encephalopathy development than other cases. Currently, ICU management of SAE is mainly based on non-pharmacological support. Pre-clinical studies have described the role of the alarmin high mobility group box 1 (HMGB1) in the complex pathogenesis of SAE. Although there are limited data available about the role of HMGB1 in neuroinflammation following sepsis, it has been implicated in other neurologic disorders, where its translocation from the nucleus to the extracellular space has been found to trigger neuroinflammatory reactions and disrupt the blood–brain barrier. Negating the inflammatory cascade, by targeting HMGB1, may be a strategy to complement non-pharmacologic interventions directed against encephalopathy. This review describes inflammatory cascades implicating HMGB1 and strategies for its use to mitigate sepsis-induced encephalopathy.

Protective role of ethyl pyruvate in spinal cord injury by inhibiting the high mobility group box-1/toll-like receptor4/nuclear factor-kappa B signaling pathway

Spinal cord injury (SCI) is a high incident rate of central nervous system disease that usually causes paralysis below the injured level. The occurrence of chronic inflammation with the axonal regeneration difficulties are the underlying barriers for the recovery of SCI patients. Current studies have paid attention to controlling the instigative and developmental process of neuro-inflammation. Ethyl pyruvate, as a derivative of pyruvate, has strong anti-inflammatory and neuroprotective functions. Herein, we reviewed the recent studies of ethyl pyruvate and high mobility group box-1 (HMGB1). We think HMGB1 that is one of the main nuclear protein mediators to cause an inflammatory response. This protein induces astrocytic activation, and promotes glial scar formation. Interestingly, ethyl pyruvate has potent inhibitory effects on HMGB1 protein, as it inhibits chronic inflammatory response by modulating the HMGB1/TLR4/NF-κB signaling pathway. This paper discusses the potential mechanism of ethyl pyruvate in inhibiting chronic inflammation after SCI. Ethyl pyruvate can be a prospective therapeutic agent for SCI.

Extracellular HMGB1 as Inflammatory Mediator in the Progression of Mycoplasma Gallisepticum Infection

High-mobility group box 1 (HMGB1), a member of damage-associated molecular patterns (DAMPs), is involved in the immune regulation of several infectious diseases. Mycoplasma gallisepticum (MG) infection is proved to cause an abnormal immune response, but the role of HMGB1 in MG-induced chronic respiratory disease (CRD) is unclear. In this study, we found that HMGB1 was released from the nucleus to the extracellular in macrophages upon infection with MG. Extracellular HMGB1 bound to TLR2 activating the NF-κB pathway triggering a severe inflammatory storm and promoting the progression of MG infection. More importantly, TLR4 could be activated by HMGB1 to trigger immune disorders after TLR2 was silenced. This disease process could be interrupted by ethyl pyruvate (EP) inhibition of HMGB1 release or glycyrrhizic acid (GA). Furthermore, treatment of MG-infected chickens with GA significantly alleviated immune organ damage. In conclusion, we demonstrate that HMGB1 is secreted extracellularly to form an inflammatory environment upon MG infection, triggering a further cellular inflammatory storm in a positive feedback approach. Blocking MG-induced HMGB1 release or suppression downstream of the HMGB1-TLR2/TLR4 axis may be a promising novel strategy for the treatment of CRD. Furthermore, this study may provide a theoretical reference for understanding non-LPS-activated TLR4 events.

Identification of Novel Immune Cell-Relevant Therapeutic Targets and Validation of Roles of TK1 in BMSCs of Systemic Lupus Erythematosus

Objective: Systemic lupus erythematosus (SLE) displays the characteristics of abnormal activity of the immune system, contributing to diverse clinical symptoms. Herein, this study was conducted for discovering novel immune cell-relevant therapeutic targets.

Methods: The abundance of diverse immune cells was estimated in PBMCs of SLE and healthy controls from the GSE50772 dataset with CIBERSORT approach. Immune cell-relevant co-expression modules were screened with WGCNA and relevant characteristic genes were determined with LASSO algorithm. Inflammatory chemokines were measured in serum of twenty SLE patients and twenty controls through ELISA. Bone marrow mesenchymal stem cells (BMSCs) were isolated and TK1 expression was measured in BMSCs through RT-qPCR and western blotting. TK1-overexpressed and TK-1-silenced BMSCs of SLE were conducted and apoptosis and cell cycle were measured with flow cytometry. Apoptosis-, cell cycle- and senescence-relevant proteins were tested with western blotting.

Results: We determined three co-expression modules strongly linked to immune cells. Five characteristic genes (CXCL1, CXCL2, CXCL8, CXCR1 and TK1) were screened and ROC curves proved the excellent diagnostic performance of this LASSO model. Inflammatory chemokines presented widespread up-regulations in serum of Systemic lupus erythematosus patients, demonstrating the activation of inflammatory response. TK1 expression was remarkably elevated in SLE BMSCs than controls. TK1 overexpression enhanced IL-1β expression, apoptosis, cell cycle arrest, and senescent phenotypes of SLE BMSCs and the opposite results were proved in TK1-silenced SLE BMSCs.

Conclusion: Collectively, our findings demonstrate that silencing TK1 alleviates inflammation, growth arrest and senescence in BMSCs of SLE, which highlights TK1 as a promising therapeutic target against SLE.

Medicinal Plant Extracts and Natural Compounds for the Treatment of Cutaneous Lupus Erythematosus: A Systematic Review

Cutaneous lupus erythematosus (CLE) is a group of autoimmune connective tissue disorders that significantly impact quality of life. Current treatment approaches typically use antimalarial medications, though patients may become recalcitrant. Other treatment options include general immunosuppressants, highlighting the need for more and more targeted treatment options. The purpose of this systematic review was to identify potential compounds that could be repurposed for CLE from natural products since many rheumatologic drugs are derived from natural products, including antimalarials. This study was registered with PROSPERO, the international prospective register of systematic reviews (registration number CRD42021251048). We comprehensively searched Ovid Medline, Cochrane Library, and Scopus databases from inception to April 27th, 2021. These terms included cutaneous lupus erythematosus; general plant, fungus, bacteria terminology; selected plants and plant-derived products; selected antimalarials; and JAK inhibitors. Our search yielded 13,970 studies, of which 1,362 were duplicates. We screened 12,608 abstracts, found 12,043 to be irrelevant, and assessed 565 full-text studies for eligibility. Of these, 506 were excluded, and 59 studies were included in the data extraction. The ROBINS-I risk of bias assessment tool was used to assess studies that met our inclusion criteria. According to our findings, several natural compounds do reduce inflammation in lupus and other autoimmune skin diseases in studies using in vitro methods, mouse models, and clinical observational studies, along with a few randomized clinical trials. Our study has cataloged evidence in support of potential natural compounds and plant extracts that could serve as novel sources of active ingredients for the treatment of CLE. It is imperative that further studies in mice and humans are conducted to validate these findings.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=251048.

Ethyl pyruvate, a versatile protector in inflammation and autoimmunity

Ethyl pyruvate (EP) has potent influence on redox processes, cellular metabolism, and inflammation. It has been intensively studied in numerous animal models of systemic and organ-specific disorders whose pathogenesis involves a strong immune component. Here, basic chemical and biological properties of EP are discussed, with an emphasis on its redox and metabolic activity. Further, its influence on myeloid and T cells is considered, as well as on intracellular signaling beyond its effect on immune cells. Also, the effects of EP on animal models of chronic inflammatory and autoimmune disorders are presented. Finally, a possibility to apply EP as a treatment for such diseases in humans is discussed. Scientific papers cited in this review were identified using the PubMed search engine that relies on the MEDLINE database. The reference list covers the most important findings in the field in the past twenty years.

Exploring microenvironment strategies to delay mesenchymal stem cell senescence

Mesenchymal stem cells (MSCs) have recently emerged as an important candidate for cell therapy and tissue regeneration. However, some limitations in translational research and therapies still exist, such as insufficient cell supply, inadequate differentiation potential, and decreased immune capacity, all of which result from replicative senescence during long-term in vitro culture. In vitro, stem cells lack a protective microenvironment owing to the absence of physical and biochemical cues compared with the in vivo niche, which provides dynamic physicochemical and biological cues. This difference results in accelerated aging after long-term in vitro culture. Therefore, it remains a great challenge to delay replicative senescence in culture. Constructing a microenvironment to delay replicative senescence of MSCs by maintaining their phenotypes, properties, and functions is a feasible strategy to solve this problem and has made measurable progress both in preclinical studies and clinical trials. Here, we review the current knowledge on the characteristics of senescent MSCs, explore the molecular mechanisms of MSCs senescence, describe the niche of MSCs, and discuss some current microenvironment strategies to delay MSCs replicative senescence that can broaden their range of therapeutic applications.

Ethyl Pyruvate Ameliorates Experimental Autoimmune Myocarditis

Ethyl pyruvate (EP) has profound anti-inflammatory and immunomodulatory properties. Here, its effects were determined on experimental autoimmune myocarditis (EAM) induced in mice by heart-specific myosin-alpha heavy chain peptide immunization. EP was applied intraperitoneally, daily, starting with the immunization. Severity of EAM was determined by histological assessment of immune cell infiltrates into the heart. Cells were phenotypically characterized by flow cytometry. Concentration of cytokines in cell culture supernatants and sera was determined by ELISA. EP reduced the infiltration of immune cells into the heart and lessened heart inflammation. Smaller number of total immune cells, as well as of CD11b⁺ and CD11c⁺ cells were isolated from the hearts of EP-treated mice. A reduced number of antigen-presenting cells, detected by anti-CD11c, MHC class II and CD86 antibodies, as well as of T helper (Th)1 and Th17 cells, detected by anti-CD4, IFN-γ and IL-17 antibodies, was determined in mediastinal lymph nodes draining the heart, in parallel. In the spleen, only the number of CD11c⁺ cells were reduced, but not of the other examined populations, thus implying limited systemic effect of EP. Reduced production of IFN-γ and IL-17 by myosin-alpha heavy chain peptide-restimulated cells of the lymph nodes draining the site of immunization was observed in EP-treated mice. Our results clearly imply that EP restrains autoimmunity in EAM. Therapeutic application of EP in the treatment of myocarditis in humans should be addressed in the forthcoming studies.

NAD+, Senolytics, or Pyruvate for Healthy Aging?

In last decades, healthy aging has become one of research hotspots in life science. It is well known that the nicotinamide adenine dinucleotide oxidized form (NAD+) level in cells decreases with aging and aging-related diseases. Several years ago, one of NAD+ precursors was first demonstrated with its new role in DNA damage repairing in mice, restoring old mice to their physical state at young ones. The finding encourages extensive studies in animal models and patients. NAD+ and its precursors have been popular products in nutrition markets. Alternatively, it was also evidenced that clearance of cellular senescence by senolytics preserved multiorgan (kidney and heart) function and extended healthy lifespan in mice. Subsequent studies confirmed findings in elderly patients subjected with idiopathic pulmonary fibrosis. The senolytic therapy is now focused on various diseases in animal and clinical studies. However, pyruvate, as both a NAD+ substitute and a new senolytic, may be advantageous, on the equimolar basis, over current products above in preventing and treating diseases and aging. Pyruvate-enriched fluids, particularly pyruvate oral rehydration salt, may be a novel intervention for diseases and aging besides critical care. Albeit the direct evidence that benefits healthy aging is still limited to date, pyruvate, as both NAD+ provider and senolytic agent, warrants intensive research to compare NAD+ or senolytics for healthy aging, specifically on the equimolar basis, in effective blood levels. This review briefly discussed the recognition of healthy aging by comparing NAD+ and Senolytics with sodium pyruvate from the clinical point of view.

Altered properties of human adipose-derived mesenchymal stromal cell during continuous in vitro cultivation

Adipose-derived stromal cells (ASCs) are now recognized as an accessible, abundant, and reliable stem cells for tissue engineering and regenerative medicine. However, ASCs should be expanded long term in order to harvest higher cell number for clinical application. In this study, ASCs isolated from human subcutaneous adipose tissue and senescence after long-term expansion was evaluated. The results showed that following in vitro expansion to the 15th passage, ASCs show changes in morphology (toward the "fried egg" morphology) and decrease in proliferation potential. Nonetheless, ASCs maintained differentiation potential toward osteoblasts, chondrocytes, and adipocytes. The senescent ASCs show impaired migration capacity under the same basal conditions. OXPHOS and glycolysis decreased slightly in culture from passage 5 to passage 15. ASCs also showed increased accumulation of beta-galactosidase in culture. Expression of senescence markers p53, p16, and p21 were also increased accompanied with the increase of passages. Experiment data showed that ASCs biological characteristics depended and changed with age. We recommend the use of early-passage cells, particularly those before passage 5, for efficacious therapeutic application of stem cells.

The emerging roles of exosomes in autoimmune diseases, with special emphasis on microRNAs in exosomes

Autoimmune diseases include rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic vasculitis, dermatomyositis, systemic sclerosis (SSc), mixed connective tissue disease, autoimmune hemolytic anemia, autoimmune thyroiditis (AITD) and ulcerative colitis. Exosomes exist in body fluids, including blood, saliva, urine, cerebrospinal fluid and milk. They are mainly derived from the invagination of intracellular lysosomal particles, which are released into the extracellular matrix after fusion of the outer membrane of the exosomes with the cell membrane. Exosomes mediate intercellular communication and regulate the biological activity of receptor cells by carrying proteins, nucleic acids and lipids. Evidences show that exosomes are involved in the pathogenesis of various autoimmune diseases. In view of the important roles of exosomes in autoimmune diseases, this work systematically reviewed the effects of exosomes on the pathogenesis of autoimmune diseases, especially the regulatory roles of exosome derived microRNAs (miRNAs) in the pathogenesis of RA, SLE, dermatomyositis, SSc, AITD and ulcerative colitis. The review of the roles of exosomes in autoimmune diseases will help to clarify the pathogenesis of these diseases and explore new diagnostic markers and therapeutic targets.

Senescent mesenchymal stem/stromal cells and restoring their cellular functions

Mesenchymal stem/stromal cells (MSCs) have various properties that make them promising candidates for stem cell-based therapies in clinical settings. These include self-renewal, multilineage differentiation, and immunoregulation. However, recent studies have confirmed that aging is a vital factor that limits their function and therapeutic properties as standardized clinical products. Understanding the features of senescence and exploration of cell rejuvenation methods are necessary to develop effective strategies that can overcome the shortage and instability of MSCs. This review will summarize the current knowledge on characteristics and functional changes of aged MSCs. Additionally, it will highlight cell rejuvenation strategies such as molecular regulation, non-coding RNA modifications, and microenvironment controls that may enhance the therapeutic potential of MSCs in clinical settings.

MicroRNA-16 directly binds to DEC2 and inactivates the TLR4 signaling pathway to inhibit lupus nephritis-induced kidney tissue hyperplasia and mesangial cell proliferation

Lupus nephritis (LN) is the most serious manifestation of systemic lupus erythematosus (SLE) and a major risk of mortality. This research focused on the function of microRNA-16 (miR-16) in LN development. Fcgamma receptor II-b-deficient (Fcgr2b^-/-) mice with the natural potential to develop SLE- and LN-like diseases were used. Gain- and loss-of-function studies were performed to explore the function of miR-16 in pathological symptoms in mouse kidney tissues and the proliferation of mesangial cells (SV40 MES-13). The putative downstream molecules of miR-16 were explored. Consequently, poor expression of miR-16 was found in kidney tissues. Upregulation of miR-16 inhibited tissue hyperplasia, inflammatory infiltration, glomerular injury and fibrosis but increased cell apoptosis in mouse kidney tissues, and it inhibited proliferation but promoted apoptosis of MES-13 cells as well. miR-16 directly bound to DEC2 and inactivated the TLR4 signaling. DEC2 blocked the protective roles of miR-16 in MES-13 cells. The enhanced proliferation in MES-13 cells following miR-16 inhibition was reversed by chloroquine phosphate, a TLR4 antagonist. To sum up, miR-16 was evidenced to have a potent protective capacity in LN through relieving the LN symptoms in kidney tissues and reducing proliferation of mesangial cells, during which DEC2 silencing and TLR4 signaling deficit were involved.

High mobility group box 1 (HMGB1): a pivotal regulator of hematopoietic malignancies

High mobility group box 1 (HMGB1) is a nonhistone chromatin-associated protein that has been widely reported to play a pivotal role in the pathogenesis of hematopoietic malignancies. As a representative damage-associated molecular pattern (DAMP), HMGB1 normally exists inside cells but can be secreted into the extracellular environment through passive or active release. Extracellular HMGB1 binds with several different receptors and interactors to mediate the proliferation, differentiation, mobilization, and senescence of hematopoietic stem cells (HSCs). HMGB1 is also involved in the formation of the inflammatory bone marrow (BM) microenvironment by activating proinflammatory signaling pathways. Moreover, HMGB1-dependent autophagy induces chemotherapy resistance in leukemia and multiple myeloma. In this review, we systematically summarize the emerging roles of HMGB1 in carcinogenesis, progression, prognosis, and potential clinical applications in different hematopoietic malignancies. In summary, targeting the regulation of HMGB1 activity in HSCs and the BM microenvironment is highly beneficial in the diagnosis and treatment of various hematopoietic malignancies.

HMGB1-Mediated Neuroinflammatory Responses in Brain Injuries: Potential Mechanisms and Therapeutic Opportunities

Brain injuries are devastating conditions, representing a global cause of mortality and morbidity, with no effective treatment to date. Increased evidence supports the role of neuroinflammation in driving several forms of brain injuries. High mobility group box 1 (HMGB1) protein is a pro-inflammatory-like cytokine with an initiator role in neuroinflammation that has been implicated in Traumatic brain injury (TBI) as well as in early brain injury (EBI) after subarachnoid hemorrhage (SAH). Herein, we discuss the implication of HMGB1-induced neuroinflammatory responses in these brain injuries, mediated through binding to the receptor for advanced glycation end products (RAGE), toll-like receptor4 (TLR4) and other inflammatory mediators. Moreover, we provide evidence on the biomarker potential of HMGB1 and the significance of its nucleocytoplasmic translocation during brain injuries along with the promising neuroprotective effects observed upon HMGB1 inhibition/neutralization in TBI and EBI induced by SAH. Overall, this review addresses the current advances on neuroinflammation driven by HMGB1 in brain injuries indicating a future treatment opportunity that may overcome current therapeutic gaps.

Increased serum calpain activity is associated with HMGB1 levels in systemic sclerosis

Background

Systemic sclerosis (SSc) or scleroderma is an intractable autoimmune disorder that affects multiple organs. The objectives were to investigate clinical correlations of serum calpain activity and high mobility group box 1 (HMGB1) levels with immunological and clinical traits.

Methods

A total of 31 patients with SSc, 20 age- and gender-matched healthy control subjects (HC), and 10 patients with other connective tissue diseases (CTD) were recruited in the study. We measured serum calpain activity and HMGB1 levels and analyzed the datasets (GSE40839, GSE48149, GSE76808, GSE81292, GSE33463, and GSE58095) from Gene Expression Omnibus (GEO) database to explore the potential mechanism by which calpain exerts its function through bioinformatics methods.

Results

Serum calpain activity was significantly increased in patients with SSc compared with those in HC and in patients with CTD and was correlated with serum HMGB1 levels, modified Rodnan skin score, erythrocyte sedimentation rate, mean platelet volume, and plateletcrit. Notably, serum calpain activity and HMGB1 levels in SSc patients with interstitial lung disease (ILD) were significantly higher than those in SSc patients without ILD. Serum calpain activity and HMGB1 levels could be the independent risk factors for SSc-ILD and novel biomarkers in patients with SSc.

Conclusion

This is the first study that reports increased serum calpain activity and the correlation between calpain and HMGB1 in patients with SSc or SSc-ILD. The serum calpain activity and HMGB1 levels may serve as measures of ILD in patients with SSc. Also, calpain and HMGB1 could be potential therapeutic targets for patients with SSc or SSc-ILD in the future.

Efficacy of mesenchymal stem cells in animal models of lupus nephritis: a meta-analysis

BACKGROUND

Lupus nephritis is usually manifested by proteinuria, active urinary sediment, hypertension, and renal failure and is a serious complication with more than 50% occurrence in systemic lupus erythematosus patients. Mesenchymal stem cells (MSC) present remarkable immunomodulatory ability, and these cells are potential therapeutic agents for autoimmune disorders. In clinical trials, the effectiveness of MSC in the treatment of lupus nephritis is still controversial. A meta-analysis was performed to assess whether MSC can achieve good efficacy in the treatment of lupus nephritis in mice.

METHODS

A comprehensive literature search was performed in Cochrane Library, ISI Web of Science, PubMed, and EMBASE from inception to Oct 1, 2019. Two authors independently extracted the data, which were pooled and calculated using RevMan 5.3.

RESULTS

A total of 28 studies met the inclusion criteria. MSC treatment resulted in lower levels of ds-DNA (OR = - 29.58, 95% CI - 29.58, - 17.99; P < 0.00001), ANA (OR = - 70.93, 95% CI - 104.55, - 37.32; P < 0.0001), Scr (OR = - 8.20, 95% CI - 12.71, - 3.69; P = 0.0004), BUN (OR = - 14.57, 95% CI - 20.50, - 8.64; P < 0.00001), proteinuria (OR = - 4.26, 95% CI - 5.15 to - 3.37; P < 0.00001), and renal sclerosis score (OR = - 1.92, 95% CI - 2.66 to - 1.18; P < 0.00001), and MSC treatment could get higher levels of albumin. To detect the potential, the cytokines were also assessed, and the MSC treatment group had lower levels of IL-2, IL-12, IL-17, and IFN-γ when compared with the control group. However, the difference was not notable for IL-4, IL-6, IL-10, TGF-β, MCP-1, TNF-α, Th1, Th17, Foxp3, or Tregs.

CONCLUSION

Our study confirmed that MSC treatment in an animal model for lupus nephritis in the studies included in the meta-analysis resulted in lower levels of ds-DNA, ANA, Scr, BUN, proteinuria, and renal sclerosis score, and MSC treatment could get higher levels of albumin.

Macrophage migration inhibitory factor rejuvenates aged human mesenchymal stem cells and improves myocardial repair

The beneficial functions of mesenchymal stem cells (MSCs) decline with age, limiting their therapeutic efficacy for myocardial infarction (MI). Macrophage migration inhibitory factor (MIF) promotes cell proliferation and survival. We investigated whether MIF overexpression could rejuvenate aged MSCs and increase their therapeutic efficacy in MI. Young and aged MSCs were isolated from the bone marrow of young and aged donors. Young MSCs, aged MSCs, and MIF-overexpressing aged MSCs were transplanted into the peri-infarct region in a rat MI model. Aged MSCs exhibited a lower proliferative capacity, lower MIF level, greater cell size, greater senescence-associated-β-galactosidase activity, and weaker paracrine effects than young MSCs. Knocking down MIF in young MSCs induced cellular senescence, whereas overexpressing MIF in aged MSCs reduced cellular senescence. MIF rejuvenated aged MSCs by activating autophagy, an effect largely reversed by the autophagy inhibitor 3-methyladenine. MIF-overexpressing aged MSCs induced angiogenesis and prevented cardiomyocyte apoptosis to a greater extent than aged MSCs, and had improved heart function and cell survival more effectively than aged MSCs four weeks after MI. Thus, MIF rejuvenated aged MSCs by activating autophagy and enhanced their therapeutic efficacy in MI, suggesting a novel MSC-based therapeutic strategy for cardiovascular diseases in the aged population.

Co-Delivery Of Dihydroartemisinin And HMGB1 siRNA By TAT-Modified Cationic Liposomes Through The TLR4 Signaling Pathway For Treatment Of Lupus Nephritis

Background and purpose

Systemic lupus erythematous (SLE) is an autoimmune disease caused by many factors. Lupus nephritis (LN) is a common complication of SLE and represents a major cause of morbidity and mortality. Previous studies have shown the advantages of multi-targeted therapy for LN and that TLR4 signaling is a target of anti-LN drugs. High-mobility group box 1 (HMGB1), a nuclear protein with a proinflammatory cytokine activity, binds specifically to TLR4 to induce inflammation. We aimed to develop PEGylated TAT peptide-cationic liposomes (TAT-CLs) to deliver anti-HMGB1 siRNA and dihydroartemisinin (DHA) to increase LN therapeutic efficiency and explore their treatment mechanism.

Methods

We constructed the TAT-CLs-DHA/siRNA delivery system using the thin film hydration method. The uptake and localization of Cy3-labeled siRNA were detected by confocal microscopy and flow cytometry. MTT assays were used to detect glomerular mesangial cell proliferation. Real-time PCR, Western blot analysis, and ELISA evaluated the anti-inflammatory mechanism of TAT-CLs-DHA/siRNA.

Results

We constructed the TAT-CLs-DHA/siRNA delivery system measuring approximately 140 nm with superior storage and serum stabilities. In vitro, it showed significantly greater uptake compared with unmodified liposomes and significant inhibition of glomerular mesangial cell proliferation. TAT-CLs-DHA/siRNA inhibited NF-κB activation in a concentration-dependent manner. Real-time PCR and Western blot analysis showed that TAT-CLs-DHA/siRNA downregulated expression of HMGB1 mRNA and protein. TAT-CLs-DHA/siRNA markedly diminished Toll-like receptor 4 (TLR4) expression and subsequent activation of MyD88, IRAK4, and NF-κB.

Conclusion

TAT-CLs-DHA/siRNA may have the potential for treatment of inflammatory diseases such as LN mediated by the TLR4 signaling pathway.