SOCS2 Binds to and Regulates EphA2 through Multiple Mechanisms

Targeting SOCS2 alleviates myocardial fibrosis by reducing nuclear translocation of β-catenin

BACKGROUND

Myocardial fibrosis is an important pathological feature of dilated cardiomyopathy (DCM). The roles of SOCS2 in fibrosis of different organs are controversial. Herein, we investigated the function and potential mechanism of SOCS2 in myocardial fibrosis.

METHODS

Bioinformatics, immunohistochemistry (IHC), immunofluorescence (IF), western blot (WB), real-time fluorescence quantitative PCR (qPCR), rat primary myocardial fibroblasts (rCFs) culture, doxorubicin (DOX) induced mouse dilated cardiomyopathy (DCM) model, and in vivo adeno-associated virus (AAV) infection were used to explore the role of SOCS2 in DCM.

RESULTS

Bioinformatics analysis showed that SOCS2 was positively correlated with fibrosis related factors. SOCS2 was significantly upregulated in patients and mice with DCM. In vivo experiments showed that targeted inhibition of cardiac SOCS2 could improve mouse cardiac function and alleviate myocardial fibrosis. Further research demonstrated that SOCS2 promoted the transformation of myofibroblasts. Knockdown of SOCS2 reduced the nuclear localization of β-catenin, which inhibited the fibrogenic effect of Wnt/β-catenin pathway. In addition, bioinformatics analysis suggested that lymphoid enhancer binding factor 1 (LEF1) was significantly positively correlated with SOCS2. Finally, dual luciferase assays demonstrated that LEF1 could bind to the promoter region of SOCS2, thereby mediating its transcriptional activation.

CONCLUSION

SOCS2 could activate the Wnt/β-catenin by regulating the nuclear translocation of β-catenin, which induces the transcriptional activation of SOCS2. Overall, these results indicated a positive feedback activation phenomenon between SOCS2, β-catenin and LEF1 in DCM. These results suggested that inhibition of SOCS2 could effectively alleviate the progression of myocardial fibrosis and improve cardiac function.

JAK inhibition increases bone mass in steady-state conditions and ameliorates pathological bone loss by stimulating osteoblast function

Janus kinase (JAK)-mediated cytokine signaling has emerged as an important therapeutic target for the treatment of inflammatory diseases such as rheumatoid arthritis (RA). Accordingly, JAK inhibitors compose a new class of drugs, among which tofacitinib and baricitinib have been approved for the treatment of RA. Periarticular bone erosions contribute considerably to the pathogenesis of RA. However, although the immunomodulatory aspect of JAK inhibition (JAKi) is well defined, the current knowledge of how JAKi influences bone homeostasis is limited. Here, we assessed the effects of the JAK inhibitors tofacitinib and baricitinib on bone phenotype (i) in mice during steady-state conditions or in mice with bone loss induced by (ii) estrogen-deficiency (ovariectomy) or (iii) inflammation (arthritis) to evaluate whether effects of JAKi on bone metabolism require noninflammatory/inflammatory challenge. In all three models, JAKi increased bone mass, consistent with reducing the ratio of receptor activator of NF-κB ligand/osteoprotegerin in serum. In vitro, effects of tofacitinib and baricitinib on osteoclast and osteoblast differentiation were analyzed. JAKi significantly increased osteoblast function (P < 0.05) but showed no direct effects on osteoclasts. Additionally, mRNA sequencing and ingenuity pathway analyses were performed in osteoblasts exposed to JAKi and revealed robust up-regulation of markers for osteoblast function, such as osteocalcin and Wnt signaling. The anabolic effect of JAKi was illustrated by the stabilization of β-catenin. In humans with RA, JAKi induced bone-anabolic effects as evidenced by repair of arthritic bone erosions. Results support that JAKi is a potent therapeutic tool for increasing osteoblast function and bone formation.

Comprehensive Evaluation of Endocytosis-Associated Protein SCAMP3 in Hepatocellular Carcinoma

Background

Secretory carrier membrane proteins 3 (SCAMP3) is an endocytosis-associated protein involved in regulating endosomal pathways and the trafficking of vital signaling receptors. This study aimed to comprehensively assess the role of SCAMP3 in hepatocellular carcinoma (HCC) by integrated bioinformatics analysis.

Methods

In this study, bioinformatics databases were used to explore the differential expression status and prognostic value of SCAMP3 gene in HCC, and bioinformatics analyses of survival data and interactors of SCAMP3 were conducted to predict the prognostic value of SCAMP3 in HCC.

Results

Using the TCGA data, our data shows that SCAMP3 mRNA expression is most significantly different between liver and hepatocellular carcinoma tissues and higher expression of SCAMP3 has unfavorable prognostic significance in HCC. Tumor grade, stage, and gender also showed a significant relevance with SCAMP3 expression. High SCAMP3 expression of males revealed significantly poorer survival and progression compared with low SCAMP3 expression of males. BioGRID statistics explores 79 unique interactions with SCAMP3 and multiple post translational modifications. Further analysis finds that SOCS2 may negatively correlate with SCAMP3, while GBA, MX1, and DDOST positively correlate with SCAMP3. Moreover, ncRNA analysis shows that SCAMP3 gene expression is positively associated with lncRNA SBF2-AS1 and negatively related with Has-miR-145. The expressions of SBF2-AS1 and Has-miR-145 are also significantly related with survival in HCC.

Discussion

SCAMP3 expression can be affected by multiple genes or ncRNAs expression that are associated with survival, thus suggesting that SCAMP3 can be used as a clinical diagnosis and prognostic biomarker in HCC.

Control of Tyrosine Kinase Signalling by Small Adaptors in Colorectal Cancer

Tyrosine kinases (TKs) phosphorylate proteins on tyrosine residues as an intracellular signalling mechanism to coordinate intestinal epithelial cell communication and fate decision. Deregulation of their activity is ultimately connected with carcinogenesis. In colorectal cancer (CRC), it is still unclear how aberrant TK activities contribute to tumour formation because TK-encoding genes are not frequently mutated in this cancer. In vertebrates, several TKs are under the control of small adaptor proteins with potential important physiopathological roles. For instance, they can exert tumour suppressor functions in human cancer by targeting several components of the oncogenic TK signalling cascades. Here, we review how the Src-like adaptor protein (SLAP) and the suppressor of cytokine signalling (SOCS) adaptor proteins regulate the SRC and the Janus kinase (JAK) oncogenic pathways, respectively, and how their loss of function in the intestinal epithelium may influence tumour formation. We also discuss the potential therapeutic value of these adaptors in CRC.