Cellular signalling最新文献

Calpain2 is a conventional member of the non-lysosomal calpain protease family that has been shown to affect the dynamics of focal and cell-cell adhesions by proteolyzing the components of adhesion complexes. Here, we inactivated calpain2 using CRISPR/Cas9 in epithelial MDCK cells. We show that depletion of calpain2 has multiple effects on cell morphology and function. Calpain2-depleted cells develop epithelial shape, however, they cover a smaller area, and cell clusters are more compact. Inactivation of calpain2 enhanced restoration of transepithelial electrical resistance after calcium switch, decreased cell migration, and delayed cell scattering induced by HGF/SF. In addition, calpain2 depletion prevented morphological changes induced by ERK2 overexpression. Interestingly, proteolysis of several calpain2 targets, including E-cadherin, β-catenin, talin, FAK, and paxillin, was not discernibly affected by calpain2 depletion. Taken together, these data suggest that calpain2 regulates the stability of cell-cell and cell-substratum adhesions indirectly without affecting the proteolysis of these adhesion complexes.

Background

Osteoporosis (OP) is a prevalent disease associated with age, and one of the primary pathologies is the defect of osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). This study aimed to elucidate whether Nuclear Receptor Binding SET Domain Protein 2 (NSD2) transcriptionally regulates osteogenic differentiation of BMSCs in osteoporosis.

Methods

Identification of human BMSCs (hBMSCs) in vitro was measured by flow cytometry. Osteogenesis of hBMSCs in vitro was measured by Alizarin Red and Alkaline Phosphatase staining. The protein levels of H3K36me1/2/3, NSD2, and Hoxa2 were measured by western blotting. The mRNA levels of NSD2, Runx2, and BSP were measured by qPCR. The role of NSD2 in the osteogenic differentiation of BMSCs was further identified by silencing NSD2 via shRNA or overexpression of NSD2 via lentivirus transfection. The interactions of NSD2, H3K36me2 and Hoxa2 were identified via chromatin immunoprecipitation (ChIP). Luciferase reporting analysis was employed to confirm that NSD2 regulated the transcriptional activity of Hoxa2. Ovariectomized (OVX) was performed on mice to construct osteoporosis (OP) model. Subsequently, the bone mass was assessed by micro computed tomography (micro-CT) scan.

Results

During the osteogenesis of OP-derived hBMSCs, the levels of NSD2 and H3K36me2 significantly increased in 14 days of osteogenic induction. Inhibition of NSD2 via shRNA increased the RUNX2 and BSP expression of hBMSCs, while overexpression of NSD2 decreased RUNX2 and BSP expression of hBMSCs. ChIP analysis indicated NSD2-mediated H3K36me2 reduced the osteogenic differentiation of hBMSCs by regulating the osteogenic inhibitor Hoxa2. Accordingly, inhibition of NSD2 in vivo via tail vein injection of LV-shNSD2 lentivirus greatly alleviated OVX-induced osteoporosis in mice.

Conclusion

We demonstrated that NSD2 inhibited the osteogenic differentiation in hBMSCs by transcriptionally downregulating Hoxa2 via H3K36me2 dimethylation. Inhibition of NSD2 effectively attenuated bone loss in murine osteoporosis and NSD2 is a promising target for clinical treatment of osteoporosis.

The social amoeba Dictyostelium discoideum has been studied for close to a century to better understand conserved cellular and developmental processes. The life cycle of this model eukaryote is composed of a unicellular growth phase and a multicellular developmental phase that is induced by starvation. When starved, individual cells undergo chemotactic aggregation to form multicellular mounds that develop into slugs. Terminal differentiation of cells within slugs forms fruiting bodies, each composed of a stalk that supports a mass of viable spores that germinate and restart the life cycle when nutrients become available. Calcium-dependent cell adhesion protein A (CadA) and countin (CtnA) are two proteins that regulate adhesion and aggregation, respectively, during the early stages of D. discoideum development. While the functions of these proteins have been well-studied, the mechanisms regulating their trafficking are not fully understood. In this study, we reveal pathways and cellular components that regulate the intracellular and extracellular amounts of CadA and CtnA during aggregation. During growth and starvation, CtnA localizes to cytoplasmic vesicles and punctae. We show that CtnA is glycosylated and this post-translational modification is required for its secretion. Upon autophagy induction, a signal peptide for secretion facilitates the release of CtnA from cells via a pathway involving the μ subunit of the AP3 complex (Apm3) and the WASP and SCAR homolog, WshA. Additionally, CtnA secretion is negatively regulated by the D. discoideum orthologs of the human non-selective cation channel mucolipin-1 (Mcln) and sorting receptor sortilin (Sort1). As for CadA, it localizes to the cell periphery in growth-phase and starved cells. The intracellular and extracellular amounts of CadA are modulated by autophagy genes (atg1, atg9), Apm3, WshA, and Mcln. We integrate these data with previously published findings to generate a comprehensive model summarizing the trafficking of CadA and CtnA in D. discoideum. Overall, this study enhances our understanding of protein trafficking during D. discoideum aggregation, and more broadly, provides insight into the multiple pathways that regulate protein trafficking and secretion in all eukaryotes.

Metabolic diseases are abnormal conditions that impair the normal metabolic process, which involves converting food into energy at a cellular level, and cause difficulties like obesity and diabetes. The study aimed to investigate how ferulic acid (FA) and its derivatives could prevent different metabolic diseases and disorders and to understand the specific molecular mechanisms responsible for their therapeutic effects. Information regarding FA associations with metabolic diseases and disorders was compiled from different scientific search engines, including Science Direct, Wiley Online, PubMed, Scopus, Web of Science, Springer Link, and Google Scholar. This review revealed that FA exerts protective effects against metabolic diseases such as diabetes, diabetic retinopathy, neuropathy, nephropathy, cardiomyopathy, obesity, and diabetic hypertension, with beneficial effects on pancreatic cancer. Findings also indicated that FA improves insulin secretion by increasing Ca²⁺ influx through the L-type Ca²⁺ channel, thus aiding in diabetes management. Furthermore, FA regulates the activity of inflammatory cytokines (TNF-α, IL-18, and IL-1β) and antioxidant enzymes (CAT, SOD, and GSH-Px) and reduces oxidative stress and inflammation, which are common features of metabolic diseases. FA also affects various signaling pathways, including the MAPK/NF-κB pathways, which play an important role in the progression of diabetic neuropathy and other metabolic disorders. Additionally, FA regulates apoptosis markers (Bcl-2, Bax, and caspase-3) and exerts its protective effects on cellular destruction. In conclusion, FA and its derivatives may act as potential medications for the management of metabolic diseases.

Background

Peyronie's disease (PD) causes benign plaques or induration in tunica albuginea (TA). Kindlin-2 regulates the TGF-β1/Smad3 pathway, which accelerates kidney fibrosis. The study is aimed mainly to investigate the impact of Kindlin-2 on PD formation and its signaling pathways, notably the TGF-β/Smad pathway in the presence of TGF-β1.

Methods

In this mouse investigation, adenovirus TGF-β1 was injected into TA to produce PD. The model was successfully induced 45 days later. Western Blot (WB) and immunohistochemistry (IHC) were utilized to measure Kindlin-2 in PD model tissue. WB and immunofluorescence assays were utilized to confirm the impact of TGF-β1 on Kindlin-2 levels in vitro. The interaction among Kindlin-2, TβRI, and Smad3 was detected using immunoprecipitation (IP) experiments. We examined how TGF-β1 affects Smad3 phosphorylation and downstream gene activation process. Finally, Kindlin-2 and the level of tissue fibrosis were examined in PD model.

Results

Kindlin-2 levels were elevated in the TGF-β1-induced PD model, confirming that TGF-β1 can increase Kindlin-2 levels in primary PD cells. Moreover, Kindlin-2 mediates Smad3-TβRI interaction, activates p-Smad3, and enhances TGF-β1 target gene expression. In vivo investigations reveal that Kindlin-2 promotes PD development and tissue fibrosis. The regulatory effects of Kindlin-2 need the presence of TGF-β1. Tissue fibrosis can be reduced by downregulating Kindlin-2.

Conclusion

Kindlin-2 does not directly activate Smad3 to induce tissue fibrosis. Instead, it exerts its effect through the combined influence of TGF-β1. Inhibiting Kindlin-2 could potentially be a treatment for PD.

The overexpression of programmed death ligand 1 (PD-L1) is associated with resistance to anticancer therapies and poor prognosis in patients with head and neck squamous cell carcinoma (HNSCC). Nimotuzumab, a humanized anti-epidermal growth factor receptor (EGFR) mAb, has been widely used clinically for treating several solid tumors. However, whether its anticancer effect involves a reduction in PD-L1 expression remains unclear. The current study aimed to investigate the regulatory effects and underlying mechanism of nimotuzumab on PD-L1 expression in HNSCC both in vitro and in vivo. In vitro, nimotuzumab inhibited IFN-γ-induced PD-L1 upregulation at both the transcriptional and protein levels in the HNSCC cell lines. Subsequent mechanism research revealed that nimotuzumab suppressed IFN-γ-stimulated PD-L1 upregulation mainly by inhibiting phosphorylation of EGFR/MEK/ERK pathway, which was further validated by MEK and ERK inhibitors. In a HNSCC tumor-bearing model, nimotuzumab significantly decreased PD-L1 expression during tumor progression or chemotherapy, and this reduction was accompanied by increased sensitivity of the tumor to docetaxel and atezolizumab. Additionally, nimotuzumab reversed PD-L1 upregulation when combined with Taxol + Cisplatin (TP) induction chemotherapy regimens and improved the CD4⁺ and CD8⁺ T cells infiltration in HNSCC patients. These findings provide new insights into the anticancer mechanisms of nimotuzumab in HNSCC.

Diabetic kidney disease (DKD) is often featured with redox dyshomeostatis. Pyruvate dehydrogenase kinase 4 (PDK4) is the hub for DKD development. However, the mechanism by which PDK4 mediates DKD is poorly understood. The current work aimed to elucidate the relationship between PDK4 and DKD from the perspective of redox manipulation. Oxidative stress was observed in the human proximal tubular cell line (HK-2 cells) treated with a high concentration of glucose and palmitic acid (HGL). The mechanistic study showed that PDK4 could upregulate Kelch-like ECH-associated protein 1 (Keap1) in HGL-treated HK-2 cells through the suppression of autophagy, resulting in the depletion of nuclear factor erythroid 2-related factor 2 (Nrf2), the master regulator of redox homeostasis. At the cellular level, pharmacological inhibition or genetic knockdown of PDK4 could boost Nrf2, followed by the increase of a plethora of antioxidant enzymes and ferroptosis-suppression enzymes. Meanwhile, the inhibition or knockdown of PDK4 remodeled iron metabolism, further mitigating oxidative stress and lipid peroxidation. The same trend was observed in the DKD mice model. The current work highlighted the role of PDK4 in the development of DKD and suggested that PDK4 might be a promising target for the management of DKD.

The dysregulation of N(7)-methylguanosine (m7G) modification is increasingly recognized as a key factor in the pathogenesis of cancers. Aberrant expression of these regulatory proteins in various cancers, including lung, liver, and bladder cancers, suggests a universal role in tumorigenesis. Studies have established a strong correlation between the expression levels of m7G regulatory proteins, such as Methyltransferase like 1 (METTL1) and WD repeat domain 4 (WDR4), and clinical parameters including tumor stage, grade, and patient prognosis. For example, in hepatocellular carcinoma, high METTL1 expression is associated with advanced tumor stage and poor prognosis. Similarly, WDR4 overexpression in colorectal cancer correlates with increased tumor invasiveness and reduced patient survival. This correlation underscores the potential of these proteins as valuable biomarkers for cancer diagnosis and prognosis. Additionally, m7G modification regulatory proteins influence cancer progression by modulating the expression of target genes involved in critical biological processes, including cell proliferation, apoptosis, migration, and invasion. Their ability to regulate these processes highlights their significance in the intricate network of molecular interactions driving tumor development and metastasis. Given their pivotal role in cancer biology, m7G modification regulatory proteins are emerging as promising therapeutic targets. Targeting these proteins could offer a novel approach to disrupt the malignant behavior of cancer cells and enhance treatment outcomes. Furthermore, their diagnostic and prognostic value could aid in the early detection of cancer and the selection of appropriate therapeutic strategies, ultimately enhancing patient management and survival rates. This review aims to explore the mechanisms of action of RNA m7G modification regulatory proteins in tumors and their potential applications in cancer progression and treatment. By delving into the roles of these regulatory proteins, we intend to provide a theoretical foundation for the development of novel cancer treatment strategies.