Single-cell sequencing reveals the antifibrotic effects of YAP/TAZ in systemic sclerosis

Atgl-dependent adipocyte lipolysis promotes lipodystrophy and restrains fibrogenic responses during skin fibrosis

During skin fibrosis, extracellular matrix (ECM) proteins are overproduced, and resident lipid-filled, mature dermal adipocytes are depleted in both human disease and mouse models. However, the mechanisms by which the reduction in lipid-filled adipocytes occurs during fibrosis are not well understood. Here, we identify that adipocyte lipolysis via the rate limiting enzyme, adipocyte triglyceride lipase (Atgl), is required for loss of adipose tissue during skin fibrosis in mice. We find that in two fibrotic mouse models, adipocyte lipolysis occurs early during skin fibrosis development and lipid storage is reestablished during fibrosis recovery. In mice lacking Atgl in adipocytes, maintenance of adipocyte lipid storage occurs in both chemical and genetic models of fibrosis development. Transcriptional analysis revealed upregulation of lipid metabolism/lipolysis genes in fibrotic patient skin. Interestingly, loss of adipocyte Atgl-driven lipolysis results in precocious, fibrotic remodeling of the dermal ECM in bleomycin treated mice as indicated by histological and transcriptional changes. These data suggest that dermal adipocyte-derived fatty acids prevent fibrotic ECM remodeling in fibroblasts during fibrosis development. Thus, we suggest that dermal adipocyte-derived fatty acids are released during fibrosis development and delay fibroblast fibrogenic responses, which may hold therapeutic potential for treating fibrotic diseases.

SALL4 mediates SHP2 inhibition in myocardial fibroblasts through the DOT1L/H3K79me2 signaling pathway to promote the progression of myocardial infarction

OBJECTIVE

To explore the influence of SALL4 in cardiac fibroblasts on the progression of myocardial infarction.

METHODS

Analysis of genes specifically expressed in myocardial infarction by bioinformatics methods; The impact of SALL4 on myocardial infarction was assessed using mouse ultrasound experiments and Masson staining; The effect of SALL4 on the expression levels of collagen-I and collagen-III in myocardial tissue was examined by immunohistochemical staining; The migration ability of cardiac fibroblasts was evaluated using a Transwell assay; The proliferative ability of cardiac fibroblasts was tested using a CCK-8 assay; The relative fluorescence intensity of α-SMA and CTGF in cardiac fibroblasts were checked through immunofluorescence staining experiment; The expression of SALL4, DOT1L, H3K79me2, P53, SHP2, YAP, nucleus-YAP, collagen-I, α-SMA, CTGF, and PAI-1 in myocardial tissues or cardiac fibroblasts was detected using western blot analysis.

RESULTS

SALL4-specific high expression in myocardial infarction; SALL4 intensified the alterations in the heart structure of mice with myocardial infarction and worsened the fibrosis of myocardial infarction; SALL4 also promoted the expression of SALL4, DOT1L, H3K79me2, P53, SHP2, YAP, nucleus-YAP, collagen-I, collagen-III, α-SMA, CTGF, and PAI-1 in myocardial infarction tissues and cardiac fibroblasts; Subsequently, SALL4 could enhance the immunofluorescence intensity of α-SMA and CTGF; Moreover, SALL4 could promote the proliferation and migration of cardiac fibroblasts.

CONCLUSION

In cardiac fibroblasts, SALL4 mediates the DOT1L/H3K79me2 signaling pathway to inhibit SHP2, which then promotes the YAP/TAZ signaling pathway, thereby facilitating the progression of myocardial infarction.

Single-cell sequencing technology in skin wound healing

Skin wound healing is a complicated biological process that mainly occurs in response to injury, burns, or diabetic ulcers. It can also be triggered by other conditions such as dermatitis and melanoma-induced skin cancer. Delayed healing or non-healing after skin injury presents an important clinical issue; therefore, further explorations into the occurrence and development of wound healing at the cellular and molecular levels are necessary. Single-cell sequencing (SCS) is used to sequence and analyze the genetic messages of a single cell. Furthermore, SCS can accurately detect cell expression and gene sequences. The use of SCS technology has resulted in the emergence of new concepts pertaining to wound healing, making it an important tool for studying the relevant mechanisms and developing treatment strategies. This article discusses the application value of SCS technology, the effects of the latest research on skin wound healing, and the value of SCS technology in clinical applications. Using SCS to determine potential biomarkers for wound repair will serve to accelerate wound healing, reduce scar formation, optimize drug delivery, and facilitate personalized treatments.

Research progress on Hippo signaling pathway effector molecules in rheumatic immune system diseases

The core components of the Hippo signaling pathway encompass upstream regulatory molecules, core kinase cascade complexes, and downstream transcriptional regulation complexes. This pathway modulates cellular behaviors by influencing the effector molecules of its core components and plays a pivotal role in immune regulation. Effector molecules,such as Yes-associated protein (YAP), transcriptional coactivator with PDZ-binding motif (TAZ), transcriptional enhanced associate domain transcriptional factor (TEAD), monopolar spindle-one binder (MOB1), large tumor suppressor (LATS), can stimulate fibroblast-like synovial cell migration and invasion in rheumatoid arthritis, regulate osteoarthritis disease progression, promote pathological new bone formation in ankylosing spondylitis, sustain submandibular gland development while delaying Sjogren's syndrome progression, mediate alpha-smooth muscle actin in systemic sclerosis, and refine the regulation of target genes associated with pulmonary fibrosis. This article provides an overview of the regulatory mechanisms involving Hippo signaling pathway-related effector molecules in the pathogenesis and progression of rheumatic immune system diseases, to serve as a reference for exploring novel therapeutic targets of rheumatic immune system diseases.

YAP/TAZ as Molecular Targets in Skeletal Muscle Atrophy and Osteoporosis

Skeletal muscles and bones are closely connected anatomically and functionally. Age-related degeneration in these tissues is associated with physical disability in the elderly and significantly impacts their quality of life. Understanding the mechanisms of age-related musculoskeletal tissue degeneration is crucial for identifying molecular targets for therapeutic interventions for skeletal muscle atrophy and osteoporosis. The Hippo pathway is a recently identified signaling pathway that plays critical roles in development, tissue homeostasis, and regeneration. The Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are key downstream effectors of the mammalian Hippo signaling pathway. This review highlights the fundamental roles of YAP and TAZ in the homeostatic maintenance and regeneration of skeletal muscles and bones. YAP/TAZ play a significant role in stem cell function by relaying various environmental signals to stem cells. Skeletal muscle atrophy and osteoporosis are related to stem cell dysfunction or senescence triggered by YAP/TAZ dysregulation resulting from reduced mechanosensing and mitochondrial function in stem cells. In contrast, the maintenance of YAP/TAZ activation can suppress stem cell senescence and tissue dysfunction and may be used as a basis for the development of potential therapeutic strategies. Thus, targeting YAP/TAZ holds significant therapeutic potential for alleviating age-related muscle and bone dysfunction and improving the quality of life in the elderly.

Recent advances in the role of Yes-associated protein in dermatosis

BACKGROUND

Dermatosis is a general term for diseases of the skin and skin appendages including scleroderma, psoriasis, bullous disease, atopic dermatitis, basal cell carcinoma, squamous cell carcinoma, and melanoma. These diseases affect millions of individuals globally and are a serious public health concern. However, the pathogenesis of skin diseases is not fully understood, and treatments are not optimal. Yes-associated protein (YAP) is a transcriptional coactivator that plays a role in the regulation of gene transcription and signal transduction.

AIMS

To study the role of Yes-associated protein in skin diseases.

MATERIALS AND METHODS

The present review summarizes recent advances in our understanding of the role of YAP in skin diseases, current treatments that target YAP, and potential avenues for novel therapies.

RESULTS

Abnormal YAP expression has been implicated in occurrence and development of dermatosis. YAP regulates the cell homeostasis, proliferation, differentiation, apoptosis, angiopoiesis, and epithelial-to-mesenchymal transition, among other processes. As well as, it serves as a potential target in many biological processes for treating dermatosis.

CONCLUSIONS

The effects of YAP on the skin are complex and require multidimensional investigational approaches. YAP functions as an oncoprotein that can promote the occurrence and development of cancer, but there is currently limited information on the therapeutic potential of YAP inhibition for cancer treatment. Additional studies are also needed to clarify the role of YAP in the development and maturation of dermal fibroblasts; skin barrier function, homeostasis, aging, and melanin production; and dermatosis.

The Molecular Mechanisms of Systemic Sclerosis-Associated Lung Fibrosis

Systemic sclerosis (SSc), also known as scleroderma, is an autoimmune disorder that affects the connective tissues and has the highest mortality rate among the rheumatic diseases. One of the hallmarks of SSc is fibrosis, which may develop systemically, affecting the skin and virtually any visceral organ in the body. Fibrosis of the lungs leads to interstitial lung disease (ILD), which is currently the leading cause of death in SSc. The identification of effective treatments to stop or reverse lung fibrosis has been the main challenge in reducing SSc mortality and improving patient outcomes and quality of life. Thus, understanding the molecular mechanisms, altered pathways, and their potential interactions in SSc lung fibrosis is key to developing potential therapies. In this review, we discuss the diverse molecular mechanisms involved in SSc-related lung fibrosis to provide insights into the altered homeostasis state inherent to this fatal disease complication.