MicroRNA-34a: A Novel Therapeutic Target in Fibrosis

Cellular Transdifferentiation: A Crucial Mechanism of Fibrosis in Systemic Sclerosis

Systemic Sclerosis (SSc) is a systemic autoimmune disease of unknown etiology with a highly complex pathogenesis that despite extensive investigation is not completely understood. The clinical and pathologic manifestations of the disease result from three distinct processes: 1) Severe and frequently progressive tissue fibrosis causing exaggerated and deleterious accumulation of interstitial collagens and other extracellular matrix molecules in the skin and various internal organs; 2) extensive fibroproliferative vascular lesions affecting small arteries and arterioles causing tissue ischemic alterations; and 3) cellular and humoral immunity abnormalities with the production of numerous autoantibodies, some with very high specificity for SSc. The fibrotic process in SSc is one of the main causes of disability and high mortality of the disease. Owing to its essentially universal presence and the severity of its clinical effects, the mechanisms involved in the development and progression of tissue fibrosis have been extensively investigated, however, despite intensive investigation, the precise molecular mechanisms have not been fully elucidated. Several recent studies have suggested that cellular transdifferentiation resulting in the phenotypic conversion of various cell types into activated myofibroblasts may be one important mechanism. Here, we review the potential role that cellular transdifferentiation may play in the development of severe and often progressive tissue fibrosis in SSc.

[Medical visit status and clinical features in patients with IgG4 related disease]

OBJECTIVE

To understand the medical treatment and clinical characteristics of patients with IgG4-related disease (IgG4-RD) with complex clinical manifestations and easy to be misdiagnosed and missed, and to improve the recognition of this disease among doctors from relevant medical departments.

METHODS

A retrospective analysis was conducted on the medical records of patients diagnosed with IgG4-RD who were hospitalized and discharged from Peking University Third Hospital from January 1, 2012 to December 31, 2022. The patient' s medical visit status, clinical manifestations, laboratory examinations, diagnosis, and treatment information were summarized.

RESULTS

A total of 116 patients diagnosed with IgG4-RD were included in this study, with a male to female ratio of 2. 52∶ 1 and an average age of (61.83±10.80) years. The departments for initial visits were gastroenterology, general surgery, and ophthalmology. While the departments responsible for definitive diagnosis were gastroenterology, rheumatology and immunology, and respiratory medicine. Twenty-one patients (18. 10%) required consultation and treatment from three or more departments before receiving a definitive diagnosis. The median time from symptom onset to the initial clinic visit was 2 (1, 7) months, and the median time from symptom onset to diagnosis was 1 (1, 12) month. Twenty-four patients (20.69%) underwent surgical resection of the affected sites before diagnosis. According to the classification criteria of IgG4-RD, sixty-eight (58.62%) cases were diagnosed definitively, eight (6.9%) cases were likely to be diagnosed, and 40 (34.48%) cases were suspected to be diagnosed. In the 68 definitively diagnosed patients, the most commonly affected organs were submandibular gland, the pancreas, biliary tract, parotid in sequence. The median serum IgG4 (IgG4, immunoglobulin G4) level was 6.16 (3. 61, 12. 30) g/L. Fifty-seven patients (83.82%) were treated with glucocorticoids, and 14 patients (20.59%) were treated with immunosuppressants. The use of immunosuppressants was mainly in the rheumatology and immunology department (78. 57%).

CONCLUSION

IgG4-RD is more common in elderly males, with submandibular gland, the pancreas, biliary tract, and parotid being most commonly affected. The distribution of initial visit departments in patients is wide. The proportion of definitive diagnosis based on pathology is relatively low. In terms of treatment, the main approach is steroid treatment, while the use of immunosuppres-sants is not widespread.

[Expression and clinical significance of plasma exosomal miR-34-5p and miR-142-3p in systemic sclerosis]

OBJECTIVE

To detect the expression of plasma exosomal microRNA (miRNA) in systemic sclerosis (SSc), and to investigate its clinical significance.

METHODS

A total of 20 patients who were initially diagnosed with SSc and did not receive medication in Department of Rheumatology and Immunology of Meizhou People' s Hospital from January 2020 to January 2022 were recruited, as well as 15 healthy individuals whose gender and age matched with those of the SSc patients. Plasma exosomes were isolated using ultracentrifugation method. The expression levels of exosomal miR-34-5p, miR-92-3p and miR-142-3p were detected by quantative real-time polymerase chain reaction (qRT-PCR). Correlations between the expression levels of exosomal miRNAs and clinical characteristic were analyzed by Spearman's rank correlation coefficient test.

RESULTS

The mean age of 20 patients with SSc was (52.6±12.6) years, including 7 males and 13 females. Among the 20 SSc patients, 13 cases were diagnosed as limited cutaneous systemic sclerosis (lcSSc) and 7 cases were diagnosed as diffuse cutaneous systemic sclerosis (dcSSc) according to the extent of skin involvement. According to the findings of high resolution chest CT, 7 of 20 SSc patients were diagnosed with interstitial lung disease (ILD) and 13 SSc patients were diagnosed with non-ILD. The expression levels of exosomal miR-34-5p, miR-92-3p and miR-142-3p were significantly elevated in the SSc patients compared with those in the healthy controls group (P=0.003, P=0.000 1, and P=0.016, respectively). Compared with the SSc patients without ILD, the expression levels of miR-34-5p and miR-142-3p were significantly lower in the SSc patients with ILD (P=0.037 and P=0.015, respectively). The expression levels of exosomal miR-34-5p and miR-142-3p showed negative correlation with ILD (r=-0.48, P=0.031 and r=-0.55, P=0.011, respectively), and arthritis (r=-0.46, P=0.040 and r=-0.48, P=0.032, respectively). The expression levels of exosomal miR-142-3p showed a negative correlation with erythrocyte sedimentation rate (ESR) (r=-0.55, P=0.012).

CONCLUSION

Plasma exosomal miR-34-5p, miR-92-3p and miR-142-3p were dysregulated in SSc. The dyregulation of exosomal miR-34-5p and miR-142-3p showed correlation with SSc associated ILD (SSc-ILD).

The potential role of miRNAs and regulation of their expression in the development of mare endometrial fibrosis

Mare endometrial fibrosis (endometrosis), is one of the main causes of equine infertility. Despite the high prevalence, both ethology, pathogenesis and the nature of its progression remain poorly understood. Recent studies have shown that microRNAs (miRNAs) are important regulators in multiple cellular processes and functions under physiological and pathological circumstances. In this article, we reported changes in miRNA expression at different stages of endometrosis and the effect of transforming growth factor (TGF)-β1 on the expression of the most dysregulated miRNAs. We identified 1, 26, and 5 differentially expressed miRNAs (DEmiRs), in categories IIA (mild fibrosis), IIB (moderate fibrosis), and III (severe fibrosis) groups compared to category I (no fibrosis) endometria group, respectively (Padjusted < 0.05, log2FC ≥ 1.0/log2FC ≤  - 1.0). This study indicated the potential involvement of miRNAs in the regulation of the process associated to the development and progression of endometrosis. The functional enrichment analysis revealed, that DEmiRs target genes involved in the mitogen-activated protein kinases, Hippo, and phosphoinositide-3-kinase (PI3K)-Akt signalling pathways, focal adhesion, and extracellular matrix-receptor interaction. Moreover, we demonstrated that the most potent profibrotic cytokine-TGF-β1-downregulated novel-eca-miR-42 (P < 0.05) expression in fibroblasts derived from endometria at early-stage endometrosis (category IIA).

Role of microRNA in non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH): a comprehensive review

Non-alcoholic fatty liver disease (NAFLD) is a prevalent liver condition that affects people who do not overconsume alcohol. Uncertainties exist over how microRNAs (miRNAs) in the blood and liver relate to NAFLD. The aim of this narrative review was to investigate the role of miRNAs in the onset and progression of non-alcoholic steatohepatitis (NASH) from NAFLD, and explore their potential as diagnostic tools and treatment targets for NAFLD patients. Liver miRNA-34a levels were found to accurately represent the degree of liver damage, with lower levels suggesting more damage. In patients with NAFLD and severe liver fibrosis, higher levels of miRNA-193a-5p and miRNA-378d were found. Moreover, miRNA-34a, miRNA-122, and miRNA-192 levels might aid in differentiating NASH from NAFLD. Similar to this, miRNA-21 and miRNA-27 levels in rats were able to distinguish between steatosis and steatohepatitis. High-fat diets enhanced the expression of 15 distinct miRNAs in rats, and there were substantial differences in the miRNA expression patterns between obese and lean people. The results from the present review imply that miRNA microarrays and sequencing may be helpful diagnostic tools, and miRNAs may be a possible treatment target for patients with NAFLD.