CTSB promotes porcine preadipocytes differentiation by degrading fibronectin and attenuating the Wnt/β-catenin signaling pathway

Myokine, a key cytokine for physical exercise to alleviate sarcopenic obesity

Skeletal muscle has a robust endocrine function as a powerful organ and can secrete and release cytokines or polypeptides known as myokines. These myokines have significant regulatory effects on signal transduction in skeletal muscle and the metabolism of peripheral tissues and organs and exert biological effects via autocrine, paracrine, or endocrine forms. Obesity and aging cause myokine secretion dysregulation, and hastening sarcopenic obesity (SO) development. Exercise is currently an excellent intervention and prevention method for SO. Meanwhile, exercise impacts many organs and tissues. These organs and tissues will produce various myokines in response to movement and metabolism throughout the body to govern muscle differentiation, growth, and remodeling. According to accumulating data, exercise can increase the release of myokines from diverse tissues into the blood and postpone the SO onset and progression by influencing protein metabolism, inflammation, mitochondrial quality control, and other mechanisms.

Cathepsin B plays a role in spermatogenesis and sperm maturation through regulating autophagy and apoptosis in mice

Spermatogenesis and sperm maturation are complex and highly ordered biological processes. Any failure or disorder in these processes can cause defects in sperm morphology, motility, and fertilization ability. Cathepsin B (CTSB) is involved in the regulation of a variety of pathological processes. In the present study, we found that CTSB was abundantly expressed in the male reproductive system, however, the specific role of CTSB in regulating spermatogenesis and sperm maturation remained elusive. Hence, we generated Ctsb ^-/- mice using CRISPR/Cas9 technology. In Ctsb ^-/- mice, sperm count was significantly decreased while the level of morphologically abnormal sperm was markedly increased. Additionally, these mice had significantly lower levels of progressive motility sperm and elevated levels of immobilized sperm. Histological analysis showed slight vacuolization in the testis epithelium, as well as the loss of epididymal epithelium cells. Further investigation showed that autophagic activity was inhibited and apoptotic activity was increased in both the testis and epididymis of Ctsb ^-/- mice. Together, our findings demonstrate that CTSB plays an important role in spermatogenesis and sperm maturation in mice.

Myostatin increases the expression of matrix metalloproteinase genes to promote preadipocytes differentiation in pigs

ABSTACTMyostatin (MSTN) resulted in reduced backfat thickness in MSTN-knockout (MSTN-KO) pigs, whereas the underlying mechanism remains elusive. In this study, RNA sequencing (RNA-seq) was used to screen differentially expressed genes (DEGs) in porcine fat tissues. We identified 285 DEGs, including 4 adipocyte differentiation-related genes (ADRGs). Matrix Metalloproteinase-2/7 (MMP-2/7), fibronectin (FN), and laminin (LN) were differentially expressed in MSTN-KO pigs compared with wild-type (WT) pigs. To investigate the molecular mechanism, we treated the preadipocytes with siRNA and recombinant MSTN protein. The results indicated that MSTN increased the expression of MMP-2/7/9 and promoted the preadipocyte differentiation. To further validate the effect of MSTN on MMP-2/7/9 expression, we treated MSTN-KO PK15 cells with recombinant MSTN protein and detected the expression of MMP-2/7/9. The data showed that MSTN increases the expression of MMP-2/7/9 in PK15. This study revealed that MSTN promoted preadipocyte differentiation and provided the basis for the mechanism of fatty deposition in pigs.

SOX4 Mediates ATRA-Induced Differentiation in Neuroblastoma Cells

Neuroblastoma (NB), which is considered to be caused by the differentiation failure of neural crest cells, is the most common extracranial malignant solid tumor in children. The degree of tumor differentiation in patients with NB is closely correlated with the survival rate. To explore the potential targets that mediate NB cell differentiation, we analyzed four microarray datasets from GEO, and the overlapping down- or upregulated DEGs were displayed using Venn diagrams. SOX4 was one of the overlapping upregulated DEGs and was confirmed by RT-qPCR and Western blot in ATRA-treated NGP, SY5Y, and BE2 cells. To clarify whether SOX4 was the target gene regulating NB cell differentiation, the correlation between the expression of SOX4 and the survival of clinical patients was analyzed via the R2 database, SOX4 overexpression plasmids and siRNAs were generated to change the expression of SOX4, RT-qPCR and Western blot were performed to detect SOX4 expression, cell confluence or cell survival was detected by IncuCyte Zoom or CCK8 assay, immunocytochemistry staining was performed to detect cells' neurites, and a cell cycle analysis was implemented using Flow cytometry after PI staining. The results showed that the survival probabilities were positively correlated with SOX4 expression, in which overexpressing SOX4 inhibited NB cell proliferation, elongated the cells' neurite, and blocked the cell cycle in G1 phase, and that knockdown of the expression of SOX4 partially reversed the ATRA-induced inhibition of NB cell proliferation, the elongation of the cells' neurites, and the blocking of the cell cycle in the G1 phase. These indicate that SOX4 may be a target to induce NB cell differentiation.

Curcumin Elevates microRNA-183-5p via Cathepsin B-Mediated Phosphatidylinositol 3-Kinase/AKT Pathway to Strengthen Lipopolysaccharide-Stimulated Immune Function of Sepsis Mice

Curcumin (Cur), a natural polyphenol compound, has been testified to modulate innate immune responses and also showed anti-inflammatory properties. Nevertheless, the mechanism was still poorly unknown, especially regarding Cur-modulated microRNAs (miRNAs) under the inflammatory response. CD39⁺ regulatory T cells (Tregs) were provided with distinct immunosuppressive action and exerted a critical role in the modulation of immune balance in sepsis. Nevertheless, the impact of Cur on the immune function of sepsis mice has not been reported. In this study, the influence of Cur on the inflammatory response and immune function of sepsis mice via augment of miR-183-5p and Cathepsin B (CTSB)-mediated phosphatidylinositol 3-kinase (PI3K)/AKT pathway was explored. Adoption of 20 mg/kg Cur was for gavage. In the meantime, injection of plasmid vectors of interference with miR-183-5p or CTSB was into the tail vein. Intraperitoneal injection of lipopolysaccharide (10 mg/kg) was to stimulate model of sepsis mice. Histopathological changes of sepsis mice were observed. The contents of tumor necrosis factor-α and Interleukin (IL)-1β and IL-6 in serum of mice were examined. Detection of alanine aminotransferase, aspartate aminotransferase (AST), urea nitrogen (BUN), and creatinine in serum of mice was performed. Test of the percentage of CD39⁺ Tregs in tail venous blood of mice was implemented. Examination of miR-183-5p, CTSB, and PI3K/AKT was performed. The targeting of miR-183-5p and CTSB was detected. Cur was available to ameliorate the histological damage, to reduce the content of inflammatory factors, AST, and BUN, and to decline the percentage of CD39⁺ Tregs in tail venous blood of sepsis mice. Elevated miR-183-5p or silenced CTSB was available to further enhance the protection of Cur. Cur was available to accelerate miR-183-5p, which negatively modulated CTSB and Cur-mediated PI3K/AKT pathway via the miR-183-5p/CTSB axis to restrain inflammation of sepsis mice and enhance its immune function.

Targeting the Wnt/β-Catenin Signaling Pathway as a Potential Therapeutic Strategy in Renal Tubulointerstitial Fibrosis

The Wnt/β-catenin signaling pathway plays important roles in embryonic development and tissue homeostasis. Wnt signaling is induced, and β-catenin is activated, associated with the development and progression of renal fibrosis. Wnt/β-catenin controls the expression of various downstream mediators such as snail1, twist, matrix metalloproteinase-7, plasminogen activator inhibitor-1, transient receptor potential canonical 6, and renin-angiotensin system components in epithelial cells, fibroblast, and macrophages. In addition, Wnt/β-catenin is usually intertwined with other signaling pathways to promote renal interstitial fibrosis. Actually, given the crucial of Wnt/β-catenin signaling in renal fibrogenesis, blocking this signaling may benefit renal interstitial fibrosis. There are several antagonists of Wnt signaling that negatively control Wnt activation, and these include soluble Fzd-related proteins, the family of Dickkopf 1 proteins, Klotho and Wnt inhibitory factor-1. Furthermore, numerous emerging small-molecule β-catenin inhibitors cannot be ignored to prevent and treat renal fibrosis. Moreover, we reviewed the knowledge focusing on anti-fibrotic effects of natural products commonly used in kidney disease by inhibiting the Wnt/β-catenin signaling pathway. Therefore, in this review, we summarize recent advances in the regulation, downstream targets, role, and mechanisms of Wnt/β-catenin signaling in renal fibrosis pathogenesis. We also discuss the therapeutic potential of targeting this pathway to treat renal fibrosis; this may shed new insights into effective treatment strategies to prevent and treat renal fibrosis.

CD147 promotes collective invasion through cathepsin B in hepatocellular carcinoma

Background

Mounting evidence suggests that solid tumors display the features of collective invasion, however, the molecular mechanisms are far from clear. This study aims to verify the role and the underlying mechanisms of CD147 in collective invasion in hepatocellular carcinoma.

Methods

Immunostaining was used to analyze human hepatocellular carcinoma specimens and three-dimensional cultures. Three-dimensional invasion model was established to mimic in vivo invasion. RNA-sequencing was used to identify downstream effectors.

Results

Human hepatocellular carcinoma underwent collective invasion and CD147 was observed to be upregulated at the invasive front of tumor cell groups. CD147 was demonstrated to promote collective invasion using the modified three-dimensional invasion model, which recapitulated the main features of collective invasion. Through transcriptome analysis and enzyme activity assay, we found that CD147 enhanced cathepsin B expression and activity. Upregulated cathepsin B in hepatocellular carcinoma cells facilitated migration and invasion, which mediated CD147-induced invasive phenotype in hepatocellular carcinoma. In terms of mechanism, we found that CD147 promoted cathepsin B transcription by activating β-catenin signaling as a result of reduced GSK-3β expression. Furthermore, we found that elevated expression of CD147 as well as cathepsin B were correlated with poor prognosis in patients with hepatocellular carcinoma.

Conclusions

CD147 promotes hepatocellular carcinoma cells collective invasion via upregulating cathepsin B expression and targeting CD147 would be valuable for the development of novel therapeutic modalities against invasion and metastasis of cancer.

Cilostazol alleviate nicotine induced cardiomyocytes hypertrophy through modulation of autophagy by CTSB/ROS/p38MAPK/JNK feedback loop

Nicotine is proved to be an important factor for cardiac hypertrophy. Autophagy is important cell recycling system involved in the regulation of cardiac hypertrophy. Cilostazol, which is often used in the management of peripheral vascular disease. However, the effects of cilostazol on nicotine induced autophagy and cardiac hypertrophy are unclear. Here, we aim to determine the role and molecular mechanism of cilostazol in alleviating nicotine-induced cardiomyocytes hypertrophy through modulating autophagy and the underlying mechanisms. Our results clarified that nicotine stimulation caused cardiomyocytes hypertrophy and autophagy flux impairment significantly in neonatal rat ventricular myocytes (NRVMs), which were evidenced by augments of LC3-II and p62 levels, and impaired autophagosomes clearance. Interestingly, cathepsin B (CTSB) activity decreased dramatically after stimulation with nicotine in NRVMs, which was crucial for substrate degradation in the late stage of autophagy process, and cilostazol could reverse this effect dramatically. Intracellular ROS levels were increased significantly after nicotine exposure. Meanwhile, p38MAPK and JNK were activated after nicotine treatment. By using ROS scavenger N-acetyl-cysteine (NAC) could reverse the effects of nicotine by down-regulation the phosphorylation of p38MAPK and JNK pathways, and pretreatment of specific inhibitors of p38MAPK and JNK could restore the autophagy impairment and cardiomyocytes hypertrophy induced by nicotine. Moreover, CTSB activity of lysosome regained after the treatment with cilostazol. Cilostazol also inhibited the ROS accumulation and the activation of p38MAPK and JNK, which providing novel connection between lysosome CTSB and ROS/p38MAPK/JNK related oxidative stress pathway. This is the first demonstration that cilostazol could alleviate nicotine induced cardiomyocytes hypertrophy through restoration of autophagy flux by activation of CTSB and inhibiting ROS/p38/JNK pathway, exhibiting a feedback loop on regulation of autophagy and cardiomyocytes hypertrophy.

Cathepsin B overexpression induces degradation of perilipin 1 to cause lipid metabolism dysfunction in adipocytes

Obesity, caused by the dysfunction of white adipose tissue (WAT), is reportedly accompanied by exacerbation of lipolysis. Perilipin 1 (PLIN1), which forms a coat around lipid droplets, interacts with several lipolysis proteins to regulate lipolysis. While it is known that perilipin family proteins are degraded in lysosomes, the underlying molecular mechanisms related to the downregulated expression of PLIN1 in obese WAT remain unknown. Recently, we found that lysosomal dysfunction originating from an abnormality of cathepsin B (CTSB), a lysosomal representative protease, occurs in obese WAT. Therefore, we investigated the effect of CTSB alterations on PLIN1 expression in obese WAT. PLIN1 protein disappeared and CTSB protein appeared in the cytoplasm of adipocytes in the early stage of obese WAT. Overexpression of CTSB reduced PLIN1 protein in 3T3L1 adipocytes, and treatment with a CTSB inhibitor significantly recovered this reduction. In addition, CTSB overexpression induced the dysfunction of lipolysis in 3T3L1 adipocytes. Therefore, we concluded that upregulation of CTSB induced the reduction of PLIN1 protein in obese WAT, resulting in lipolysis dysfunction. This suggests a novel pathology of lipid metabolism involving PLIN1 in adipocytes and that CTSB might be a therapeutic candidate molecule for obese WAT.

The role of cathepsin B in autophagy during obesity: A systematic review

White adipose tissue (WAT) regulates energy homeostasis by releasing adipokines and modulating cell maintenance. Nutrient excess affects adipocyte hypertrophy directly in WAT by increasing excessively the activity of autophagy systems, generating proinflammatory markers and increasing infiltration of macrophages, causing metabolic diseases such as obesity and diabetes. Evidences suggest that cathepsin B (CTSB), a papain-like cysteine peptidase protein, can modulate autophagy processes in adipocytes. This review will focus on the role of CTSB in autophagy under conditions of obesity.

RAI3 knockdown promotes adipogenic differentiation of human adipose-derived stem cells by decreasing β-catenin levels

Retinoic acid-induced protein 3 (RAI3) has been found to play significant roles in embryonic development, cellular proliferation and differentiation, but its role in adipogenesis has not been explored. In this study, we discovered RAI3 was downregulated during the adipogenic differentiation of human adipose derived stem cells (hASCs). Moreover, we demonstrated that knockdown of RAI3 promoted adipogenic differentiation of hASCs both in vitro and in vivo. Mechanistically, our findings showed that inhibition of RAI3 in hASCs reduced the expression of β-catenin, and lithium chloride which can activate the β-catenin pathway abolished the effect of RAI3 knockdown on the adipogenesis. These results suggest RAI3 plays an important role in adipogenesis of hASCs and may have a potential use in the future application.

HABP2 p.G534E variant in patients with family history of thyroid and breast cancer

Familial Papillary Thyroid Carcinoma (PTC) has been described as a hereditary predisposition cancer syndrome associated with mutations in candidate genes including HABP2. Two of 20 probands from families with history of PTC and breast carcinoma (BC) were evaluated by whole exome sequencing (WES) revealing HABP2 p.G534E. Sanger sequencing was used to confirm the involvement of this variant in three families (F1: 7 relatives; F2: 3 and F3: 3). The proband and his sister (with no malignant tumor so far) from F1 were homozygous for the variant whereas one relative with PTC from F2 was negative for the variant. Although the proband of the F3 with PTC was HABP2 wild type, three relatives presented the variant. Five of 170 healthy Brazilian individuals with no family history of BC or PTC and three of 50 sporadic PTC presented the p.G534E. These findings suggested no association of this variant with our familial PTC cases. Genes potentially associated with deregulation of the extracellular matrix organization pathway (CTSB, TNXB, COL4A3, COL16A1, COL24A1, COL5A2, NID1, LOXL2, MMP11, TRIM24 and MUSK) and DNA repair function (NBN and MSH2) were detected by WES, suggesting that other cancer-associated genes have pathogenic effects in the risk of familial PTC development.

Association study between single nucleotide polymorphisms in porcine genes and pork quality traits for fresh consumption and processing into Italian dry-cured ham

Single nucleotide polymorphisms (SNPs) of six genes (TTN, PRKAG3, CAST, CTSB, CTSF, and MYPN), known for associations with carcass and meat quality traits, post mortem proteolysis, were screened in a commercial crossed population of 368 heavy pigs (Large White x Landrace)×Duroc, reared according to the rules of Italian Protected Designation of Origin (PDO) dry-cured ham. Carcass, longissimus thoracis et lumborum muscle (LTL), and green ham traits were obtained after slaughtering, main weight losses of dry-cured hams were collected during processing. The results showed the impact of CAST variants on carcass weight, of CTSF on LTL tenderness, ham weight and fatness, of PRKAG3 and TTN on ultimate pH, hamweight. This study, while confirming significant associations between SNPs of genes and qualitative traits of carcass, longissimus and ham, supports CTSF as candidate gene suitable for fresh consumption purpose (tenderness of longissimus at 24h post mortem), and for dry-cured ham processing (higher thickness of ham subcutaneous fat).

Characterization and function of a cathepsin B in red crayfish (Procambarus clarkii) following lipopolysaccharide challenge

Cathepsin B is a lysosomal cysteine protease of the papain-like enzyme family with multiple biological functions. In the present study, a cathepsin B gene (named PcCTSB) was cloned and characterized from the red crayfish, Procambarus clarkii. The cDNA fragments of PcCTSB was 990 bp in length. It encoded a putative protein of 329 amino acid residues with predicted molecular weight of 36.4 kDa and isoelectric point of 7.020. Sequence alignment revealed that PcCTSB protein is 53.6%-80.4% identical with those from other 10 species. The predicted tertiary structure of PcCTSB protein was highly similar to that of animals. The results of the phylogenetic analysis indicated that the PcCTSB protein could be clustered with the Eriocheir sinensis cathepsin B protein. The recombinant protein of PcCTSB was expressed successfully in Escherichia coli cells. The mRNA expressions of PcCTSB were detected in all tested tissues, particularly high in the hepatopancreas. After lipopolysaccharide (LPS) challenge, the expression levels of PcCTSB were up-regulated significantly at different time points compared with control. Our results suggested that the PcCTSB might play an important role in defending against the pathogenes infection.