Mysm1 epigenetically regulates the immunomodulatory function of adipose-derived stem cells in part by targeting miR-150

Deubiquitinase MYSM1: An Important Tissue Development and Function Regulator

MYSM1, a deubiquitinating enzyme, plays a pivotal role in diverse biological processes. Both MYSM1 knockout mice and patients with Mysm1 gene mutations exhibit developmental abnormalities across multiple tissues and organs. Serving as a crucial regulator, MYSM1 influences stem cell function, immune responses, and the pathogenesis of diverse diseases. This review comprehensively details MYSM1's deubiquitinating activities in both the nucleus and cytoplasmic compartments, its effects on stem cell proliferation, differentiation, and immune cell function, and its involvement in cancer, aging, and depression. The high sequence homology between murine and human MYSM1, along with similar phenotypes observed in Mysm1-deficient models, provides valuable insights into the etiology of human Mysm1-deficiency syndromes. This review aims to offer a foundation for future comprehensive research on MYSM1.

Suppression of mir-150-5p attenuates the anti-inflammatory effect of glucocorticoids in mice with ulcerative colitis

Glucocorticoids have been widely used in the treatment of ulcerative colitis, but not all patients benefit from this therapy due to hormone resistance. Mir-150-5p has been reported to enhance the efficacy of glucocorticoids, and low serum mir-150-5p expression has been linked to glucocorticoid resistance in ulcerative colitis patients. The aim of this study was to elucidate the mechanisms of mir-150-5p regulation on glucocorticoid resistance. An ulcerative colitis mouse model was used to evaluate changes in ulcerative colitis symptoms, inflammatory factors, and glucocorticoid resistance-related gene expression. The results showed that mir-150-5p suppression with antagomirs did not significantly interfere with or enhance the induction of ulcerative colitis symptoms by dextran sulfate sodium, but it did attenuate the inflammation inhibitory effect of dexamethasone by abnormally regulating the expression of IL-17a, IL-10, IL-2 and IL-6 levels and myeloperoxidase activity. Mir-150-5p inhibition also induced a glucocorticoid-resistant gene expression profile in colon tissues of ulcerative colitis mice, with upregulation of p-ERK, p-JNK, and HSP90 and downregulation of p-GRa, FKBP4, and HDAC2 expression. Our results indicate that mir-150-5p suppression attenuates the anti-inflammatory effect of glucocorticoids and may function as a driver element in ulcerative colitis glucocorticoid resistance. AVAILABILITY OF DATA AND MATERIALS: All data and figures analyzed in this study are available from the corresponding author by request.

Deubiquitinase catalytic activity of MYSM1 is essential in vivo for hematopoiesis and immune cell development

Myb-like SWIRM and MPN domains 1 (MYSM1) is a chromatin binding protein with deubiquitinase (DUB) catalytic activity. Rare MYSM1 mutations in human patients result in an inherited bone marrow failure syndrome, highlighting the biomedical significance of MYSM1 in the hematopoietic system. We and others characterized Mysm1-knockout mice as a model of this disorder and established that MYSM1 regulates hematopoietic function and leukocyte development in such models through different mechanisms. It is, however, unknown whether the DUB catalytic activity of MYSM1 is universally required for its many functions and for the maintenance of hematopoiesis in vivo. To test this, here we generated a new mouse strain carrying a Mysm1^D660N point mutation (Mysm1^DN) and demonstrated that the mutation renders MYSM1 protein catalytically inactive. We characterized Mysm1^DN/DN and Mysm1^fl/DN Cre^ERT2 mice, against appropriate controls, for constitutive and inducible loss of MYSM1 catalytic function. We report a profound similarity in the developmental, hematopoietic, and immune phenotypes resulting from the loss of MYSM1 catalytic function and the full loss of MYSM1 protein. Overall, our work for the first time establishes the critical role of MYSM1 DUB catalytic activity in vivo in hematopoiesis, leukocyte development, and other aspects of mammalian physiology.

The impact of non-coding RNAs on macrophage polarization

Macrophage polarization is a process through which macrophages attain unique functional features as a response to certain stimuli from their niche. Lipopolysaccharide and Th1 cytokines induce generation of M1 macrophages. On the other hand, IL-4, IL-13, IL-10, IL-33, and TGF-β induce polarization of macrophages towards M2 phenotype. This process is also modulated by a number of miRNAs and lncRNAs. miR-375, miR-let7, miR-34a, miR-155, miR-124, miR-34a, miR-511-3p, miR-99a, miR-132 and miR-145-3p are among miRNAs that regulate macrophage polarization. Meanwhile, macrophage polarization is influenced by some lncRNAs such as H19, NRON, MEG3, GAS5, RN7SK, and AK085865. Macrophage polarization has functional significance in a wide range of human disorders particularly immune disorders and cancer. In addition, the effect of certain drugs in modulation of macrophage polarization is exerted through modulation of expression of non-coding RNAs. In the current manuscript, we provide a summary of studies aimed to identification of this aspect of non-coding RNAs.

The impact of non-coding RNAs on normal stem cells

Self-renewal and differentiation into diverse cells are two main characteristics of stem cells. These cells have important roles in development and homeostasis of different tissues and are supposed to facilitate tissue regeneration. Function of stem cells is regulated by dynamic interactions between external signaling, epigenetic factors, and molecules that regulate expression of genes. Among the highly appreciated regulators of function of stem cells are long non-coding RNAs (lncRNAs) and microRNAs (miRNAs). Impact of miR-342-5p, miR-145, miR-1297, miR-204-5p, miR-132, miR-128-3p, hsa-miR-302, miR-26b-5p and miR-10a are among miRNAs that regulate function of stem cells. Among lncRNAs, AK141205, ANCR, MEG3, Pnky, H19, TINCR, HULC, EPB41L4A-AS1 and SNHG7 have important roles in the regulation of stem cells. In the current paper, we aimed at reviewing the importance of miRNAs and lncRNAs in differentiation of stem cells both in normal and diseased conditions. For this purpose, we searched PubMed/Medline and google scholar databases using "stem cell" AND "lncRNA", or "long non-coding RNA", or "microRNA" or "miRNA".

Deubiquitinase MYSM1 in the Hematopoietic System and beyond: A Current Review

MYSM1 has emerged as an important regulator of hematopoietic stem cell function, blood cell production, immune response, and other aspects of mammalian physiology. It is a metalloprotease family protein with deubiquitinase catalytic activity, as well as SANT and SWIRM domains. MYSM1 normally localizes to the nucleus, where it can interact with chromatin and regulate gene expression, through deubiquitination of histone H2A and non-catalytic contacts with other transcriptional regulators. A cytosolic form of MYSM1 protein was also recently described and demonstrated to regulate signal transduction pathways of innate immunity, by promoting the deubiquitination of TRAF3, TRAF6, and RIP2. In this work we review the current knowledge on the molecular mechanisms of action of MYSM1 protein in transcriptional regulation, signal transduction, and potentially other cellular processes. The functions of MYSM1 in different cell types and aspects of mammalian physiology are also reviewed, highlighting the key checkpoints in hematopoiesis, immunity, and beyond regulated by MYSM1. Importantly, mutations in MYSM1 in human were recently linked to a rare hereditary disorder characterized by leukopenia, anemia, and other hematopoietic and developmental abnormalities. Our growing knowledge of MYSM1 functions and mechanisms of actions sheds important insights into its role in mammalian physiology and the etiology of the MYSM1-deficiency disorder in human.

Immunomodulatory Effect of Adipose-Derived Stem Cells: The Cutting Edge of Clinical Application

Adipose-derived stem cells (ASCs) represent a promising tool for soft tissue engineering as well as for clinical treatment of inflammatory and autoimmune pathologies. The well-characterized multi-differentiation potential and self-renewal properties of ASCs are coupled with their immunomodulatory ability in providing therapeutic efficacy. Yet, their impact in immune or inflammatory disorders might rely both on cell contact-dependent mechanisms and paracrine effects, resulting in the release of various soluble factors that regulate immune cells functions. Despite the widespread use of ASCs in clinical trials addressing several pathologies, the pathophysiological mechanisms at the basis of their clinical use have been not yet fully investigated. In particular, a thorough analysis of ASC immunomodulatory potential is mandatory. Here we explore such molecular mechanisms involved in ASC immunomodulatory properties, emphasizing the relevance of the milieu composition. We review the potential clinical use of ASC secretome as a mediator for immunomodulation, with a focus on in vitro and in vivo environmental conditions affecting clinical outcome. We describe some potential strategies for optimization of ASCs immunomodulatory capacity in clinical settings, which act either on adult stem cells gene expression and local microenvironment. Finally, we discuss the limitations of both allogeneic and autologous ASC use, highlighting the issues to be fixed in order to significantly improve the efficacy of ASC-based cell therapy.

miR-129-5p Regulates the Immunomodulatory Functions of Adipose-Derived Stem Cells via Targeting Stat1 Signaling

Adipose-derived stem cells (ASCs) have become one of the most promising stem cell populations for cell-based therapies in regenerative medicine and for autoimmune disorders owing to their multilineage differentiation and immunomodulatory capacities, respectively. One advantage of ASC-based therapy lies in their immunosuppressive potential. However, how to get ASCs to provide consistent immunosuppression remains unclear. In the current study, we found that miR-129-5p was induced in ASCs treated with inflammatory factors. ASCs with miR-129-5p knockdown exhibited enhanced immunosuppressive capacity, as evidenced by reduced expression of proinflammatory factors, with concurrent increased expression of inducible nitric oxide synthases (iNOS) and nitric oxide (NO) production. These cells also had an increased capacity to inhibit T cell proliferation in vitro. ASCs with miR-129-5p knockdown alleviated inflammatory bowel diseases and promoted tumor growth in vivo. Consistently, ASCs that overexpressed miR-129-5p exhibited reduced iNOS expression. Furthermore, we show that miR-129-5p knockdown in ASCs results in hyperphosphorylation of signal transducer and activator of transcription 1 (Stat1). When fludarabine, an inhibitor of Stat1 activation, was added to ASCs with miR-129-5p knockdown, iNOS mRNA and protein levels were significantly reduced. Collectively, these results reveal a new role for miR-129-5p in regulating the immunomodulatory activities of ASCs by targeting Stat1 activation. These novel insights into the mechanisms of ASC immunoregulation may lead to the consistent production of ASCs with strong immunosuppressive functions and thus better clinical utility of these cells.

Mysm1 epigenetically regulates the immunomodulatory function of adipose-derived stem cells in part by targeting miR-150

Adipose‐derived stem cells (ASCs) are highly attractive for cell‐based therapies in tissue repair and regeneration because they have multilineage differentiation capacity and are immunosuppressive. However, the detailed epigenetic mechanisms of their immunoregulatory capacity are not fully defined. In this study, we found that Mysm1 was induced in ASCs treated with inflammatory cytokines. Adipose‐derived stem cells with Mysm1 knockdown exhibited attenuated immunosuppressive capacity, evidenced by less inhibition of T cell proliferation, more pro‐inflammatory factor secretion and less nitric oxide (NO) production in vitro. Mysm1‐deficient ASCs exacerbated inflammatory bowel diseases but inhibited tumour growth in vivo. Mysm1‐deficient ASCs also showed depressed miR‐150 expression. When transduced with Mysm1 overexpression lentivirus, ASCs exhibited enhanced miR‐150 expression. Furthermore, Mysm1‐deficient cells transduced with lentivirus containing miR‐150 mimics produced less pro‐inflammatory factors and more NO. Our study reveals a new role of Mysm1 in regulating the immunomodulatory activities of ASCs by targeting miR‐150. These novel insights into the mechanisms through which ASCs regulate immune reactions may lead to better clinical utility of these cells.