Cell Communication and Signaling最新文献

Background: The insulin-like growth factor 2 (IGF2) is overexpressed in 90% of adrenocortical carcinomas (ACC) and promotes cell proliferation via IGF1R and isoform A of insulin receptor (IRA). However, IGF2 role in ACC tumourigenesis has not been completely understood yet, and the contribution of IGF1R and IRA in mediating ACC cell growth has been poorly explored. This study aimed to investigate IGF1R and IR expression and localisation, including the expression of IR isoforms, in ACC and adrenocortical adenomas (ACA), and their role in IGF2-driven proliferation.

Methods: Immunohistochemistry staining of IGF1R and IR was performed on 118 ACC and 22 ACA to evaluate their expression and cellular localisation and statistical analyses were carried out to assess correlations with clinicopathological data. The expression of IRA and IRB in ACC and ACA tissues, ACC cell lines and ACC and ACA primary cultures was determined by RT-qPCR. To appraise the specific role of IGF1R and IR in mediating IGF2 mitogenic pathway, single and double silencing of receptors and their inhibition in 2 ACC cell lines derived from primary tumours (H295R and JIL-2266) and 2 derived from metastatic tumours (MUC-1 and TVBF-7) as well as in ACC and ACA primary cultures were performed.

Results: We found a higher IGF1R plasma membrane localisation in ACC compared to ACA. In ACC this localisation was associated with higher Ki67 and Weiss score. IR was expressed in about half of ACC and in all ACA but, in ACC, it was associated with higher Ki67 and Weiss score. RT-qPCR revealed that the prevalent isoform of IR was IRA in ACC and ACA, but not in normal adrenals. In ACC cell lines, double IGF1R + IR silencing reduced cell proliferation in JIL-2266, MUC-1 and TVBF-7 but not in H295R. In ACC, but not ACA, primary cultures, cell proliferation was reduced after IR but not IGF1R knockdown.

Conclusions: Overall, these data suggest that IGF1R localisation and IR expression represent new biomarkers predicting tumour aggressiveness, as well as possible molecular markers useful to patients' stratification for more individualized IGF1R-IR targeted therapies or for novel pharmacological approaches specifically targeting IRA isoform.

Background: Sos1 and Sos2 are guanine-nucleotide exchange factors for Ras and Rac small GTPases, which are involved in a wide range of cellular responses including proliferation and migration. We have previously shown that Sos1 and Sos2 have different effects on cell migration, but the underlying mechanisms are not clear.

Methods: Using a 4-hydroxytamoxifen-inducible conditional Sos1^KO mutation, here we evaluated the functional specificity or redundancy of Sos1 and Sos2 regarding the control of cell migration and dynamics of focal adhesions (FAs) in primary mouse embryonic fibroblasts (MEFs).

Results: Functional analysis of the transcriptome of primary Sos1/2^WT, Sos1^KO, Sos2^KO and Sos1/2^DKO-MEFs revealed a specific, dominant role of Sos1 over Sos2 in transcriptional regulation. Sos1^KO MEFs had an increased number and stability of focal adhesions (FAs) and curbed protrusion and spreading. Conversely, Sos2^KO MEFs displayed unstable FAs with increased protrusion. Interestingly, Sos1, but not Sos2, ablation reduced the levels of GTP-bound Rac at the leading edge. In 3D, however, only Sos1/2^KO MEFs showed increased invasion and matrix degradative capacity, which correlated with increased expression of the Mmp2 and Mmp9 gelatinases. Moreover, increased matrix degradation in Sos1/2^KO MEFs was abrogated by treatment with Mmp2/9 inhibitors.

Conclusions: Our data demonstrate that Sos1 and Sos2 have different functions in FAs distribution and dynamics in 2D whereas in 3D they act together to regulate invasion and unveil a previously undescribed mechanistic connection between Sos1/2 and the regulation of Mmp2/9 expression in primary MEFs.

Background: Atrial fibrillation (AF) is the most common form of arrhythmia and is a growing clinical problem. Post-translational modifications (PTMs) constitute crucial epigenetic mechanisms but modification of lysine 2-hydroxyisobutyrylation (K_hib) in AF is still unknown. This study aimed to investigate the role and mechanism of K_hib in AF.

Methods: PTM proteomics was applied in the human atrial tissue from AF and sinus rhythm patients with heart valve disease during cardiac surgery to identify the K_hib sites. The functional changes of differential modification sites were further validated at the cellular level. Cellular electrophysiology was performed to record the ion channel current and action potential duration (APD).

Results: The modification of 124 K_hib sites in 35 proteins and 67 sites in 48 proteins exhibited significant increase or decrease in AF compared to sinus rhythm. Ten K_hib sites were included in energy metabolism-related signaling pathways (HXK1, TPIS, PGM1, and ODPX in glycolysis; MDHC and IDH3A in tricarboxylic acid cycle; NDUS2, ETFB, ADT3, and ATPB in oxidative respiratory chain). Importantly, decreased HXK1 K418_hib regulated by HDAC2 attenuated the original chemical binding domain between HXK1 and glucose, inhibited the binding ability between HXK1 and glucose, and reduced catalytic ability of the enzyme, resulting in low production of glucose-6-phosphate and ATP. Further, it also increased Kir6.2 protein and the current of K_ATP channel, and decreased APD.

Conclusions: This study demonstrates the importance of K_hib to catalysis of HXK1 and reveals molecular mechanisms of HXK1 K418_hib in AF, providing new insight into strategies of AF.

Background: Macrophages are required for development and tissue repair and protect against microbial attacks. In response to external signals, monocytes differentiate into macrophages, but our knowledge of changes that promote this transition at the level of mRNA processing, in particular mRNA polyadenylation, needs advancement if it is to inform new disease treatments. Here, we identify CFIm25, a well-documented regulator of poly(A) site choice, as a novel mediator of macrophage differentiation.

Methods: CFIm25 expression was analyzed in differentiating primary human monocytes and monocytic cell lines. Overexpression and depletion experiments were performed to assess CFIm25's role in differentiation, NF-κB signaling, and alternative polyadenylation (APA). mRNA 3' end-focused sequencing was conducted to identify changes in poly(A) site use of genes involved in macrophage differentiation and function. Cell cycle markers, NF-κB pathway components, and their targets were examined. The role of CFIm25 in NF-κB signaling was further evaluated through chemical inhibition and knockdown of pathway regulators.

Results: CFIm25 showed a striking increase upon macrophage differentiation, suggesting it promotes this process. Indeed, CFIm25 overexpression during differentiation amplified the acquisition of macrophage characteristics and caused an earlier slowing of the cell cycle, a hallmark of this transition, along with APA-mediated downregulation of cyclin D1. The NF-κB signaling pathway plays a major role in maturation of monocytes to macrophages, and the mRNAs of null, TBL1XR1, and NFKB1, all positive regulators of NF-κB signaling, underwent 3'UTR shortening, coupled with an increase in the corresponding proteins. CFIm25 overexpression also elevated phosphorylation of the NF-κB-p65 transcription activator, produced an earlier increase in the NF-κB targets p21, Bcl-XL, ICAM1 and TNF-α, and resulted in greater resistance to NF-κB chemical inhibition. Knockdown of Tables 2 and TBL1XR1 in CFIm25-overexpressing cells attenuated these effects, reinforcing the mechanistic link between CFIm25-regulated APA and NF-κB activation. Conversely, depletion of CFIm25 hindered differentiation and led to lengthening of NFKB1, TAB2, and TBL1XR1 3' UTRs.

Conclusions: Our study establishes CFIm25 as a key mediator of macrophage differentiation that operates through a coordinated control of cell cycle progression and NF-κB signaling. This linkage of mRNA processing and immune cell function also expands our understanding of the role of alternative polyadenylation in regulating cell signaling.

As a gatekeeper of the airway epithelial cells, E-cadherin is not only a critical component for the maintenance of epithelial integrity, but also engaged in pathological processes through the release of a soluble form (sE-cadherin). This study was aimed to investigate the role of sE-cadherin in ALI/ARDS. Serum samples from patients with ARDS and healthy volunteers were collected for the detection of sE-cadherin. An LPS-induced mouse model was induced to analyze the expression of sE-cadherin, and a neutralizing antibody against sE-cadherin (DECMA-1) was given to the LPS-exposed mice. The effects of recombinant sE-cadherin were tested both in vitro and in vivo, and VEGFR2 inhibition was used to explore a possible mechanism for sE-cadherin-induced pulmonary inflammation. We observed an increased level of sE-cadherin in ARDS patients as well as in LPS-exposed mice. In vivo treatment of DECMA-1 significantly attenuated LPS-induced inflammation. In vitro, exogenous sE-cadherin can dramatically upregulate the expression of VEGF in THP1-derived macrophages and human primary macrophages. In addition, intratracheal instillation of recombinant sE-cadherin leads to significant increased infiltration of neutrophils as well as overproduction of IL-6 and IL1β, which could be attenuated by inhibition of VEGF/VEGFR2 signaling. While blockade of the VEGF/VEGFR2 pathway inhibited pulmonary inflammatory responses in LPS-exposed mice. Taken together, our data demonstrated that sE-cadherin contributes to lung inflammation in ALI/ARDS, which is related to activation of the VEGF/VEGFR2 pathway.

Peritoneal dialysis (PD) is considered a life-saving treatment for end-stage renal disease. However, prolonged PD use can lead to the development of peritoneal fibrosis (PF), diminishing its efficacy. Peritoneal mesothelial cells (PMCs) are key initiators of PF when they become damaged. Exposure to high glucose‑based peritoneal dialysis fluids (PDFs) contributes to PF development by directly affecting highly metabolically active PMCs. Recent research indicates that PMCs undergo metabolic reprogramming when exposed to high-glucose PDFs, including enhanced glycolysis, impaired oxidative phosphorylation, abnormal lipid metabolism, and mitochondrial dysfunction. Although this metabolic transition temporarily compensates for the cellular damage and maintains energy levels, its long-term impact on peritoneal tissue is concerning. Multiple studies have identified a close association between this shift in energy metabolism and PF, and may promote the progression of PF through various molecular mechanisms. This review explores recent findings regarding the role and mechanism of PMC metabolic reprogramming in PF progression. Moreover, it provides a summary of potential therapeutic strategies aimed at various metabolic processes, including glucose metabolism, lipid metabolism, and mitochondrial function. The review establishes that targeting metabolic reprogramming in PMCs may be a novel strategy for preventing and treating PD-associated fibrosis.

Apolipoprotein E (APOE) has garnered significant attention as one of the most influential genetic risk factors for Alzheimer's disease (AD). While the pathogenic role of APOE4 in sporadic AD has been extensively studied, research on the protective effects of the APOE2 genotype and its underlying mechanisms remains limited. Additionally, the existence of sex differences in the protective effects of ApoE2 continues to be a topic of debate. In this study, we utilized humanized ApoE2- and ApoE3- target replacement mice to examine the sex-specific effects of ApoE2 on cognition. Compared with female ApoE3 mice, we found significantly lower spatial cognitive ability and impaired hippocampal synaptic ultrastructure in aged female ApoE2 mice, accompanied by reduced insulin signaling of the hippocampus. Further analyses by target metabolomics and transcriptomic analyses revealed that female ApoE2 mice exhibit an age-related decline in hippocampal inositol levels, and that alterations in inositol levels lower insulin signaling. Importantly, inositol supplementation was found to alleviate peripheral glucose intolerance, enhance insulin signaling, and ultimately improve cognitive function. Interestingly, these differences were not observed between male ApoE2 and ApoE3 mice. The research findings not only provide new insights into the impact of ApoE2 on cognition but also offer a new strategy for cognitive improvement through inositol supplementation in older women.

Background: Extracellular matrix (ECM) and angiogenesis are critical controls of wound regeneration, and their dysfunction delays diabetes recovery. CXXC5 belongs to the CXXC protein family that can regulate the function of human dermal fibroblasts (HDFs) and human umbilical vein endothelial cells (HUVECs); However, awareness of its functional role remains limited.

Methods: Mice were divided into control (CON), diabetic (DM), diabetic + KY19382 (DM + KY19382), and diabetic + vehicle (DM + Vehicle) groups. HDFs and HUVECs were stimulated under different CXXC5 conditions and mice were treated with KY19382, followed by the application of assays including Western blotting (WB), immunofluorescence (IF) and quantitative reverse transcription-PCR (qRT-PCR) to assess wound healing and molecular signaling.

Results: Mice in DM had fewer blood vessels, a slower wound healing rate, and more disrupted collagen than CON. Application of KY19382 improved these conditions, which promoted fibroblast activation and vascularization in high glucose environments and DM. Mechanistically, blocking CXXC5 promotes Wnt/β-catenin-mediated stabilization by reducing the binding of the deterrent factor CTBP1 to β-catenin, which induces dermal fibroblast activation and facilitates HUVECs tube formation and migration via VEGFA/VEGFR2 and NFκB signaling pathways. KY19382 promotes HUVECs activation by blocking CTBP1 transcription to activate the NFκB signaling pathway, thus wound re-vascularization.

Conclusion: CXXC5 is an essential regulatory factor of wound healing and a prospective therapeutic target for treating chronic wound damage in diabetes.

The leucine rich repeat and sterile alpha motif containing 1 (LRSAM1) as E3 ligase recognizes bacteria and generates a ubiquitin signal to initiate the autophagy process. In the present study, LRSAM1 was identified from the Pacific oyster Crassostrea gigas (designed as CgLRSAM1), which was able to recognize various pathogen-associated molecular patterns and bacteria and directly ubiquitinate Vibrio splendidus. V. splendidus was co-localized with CgLRSAM1 and ubiquitin after invading haemocytes, and the ubiquitinated V. splendidus was then internalized into haemocyte lysosomes by p62-LC3-mediated autophagy. In haemocytes of CgLRSAM1-RNAi oysters, the activation of CgLC3 was enhanced after V. splendidus stimulation. While the co-localization values of V. splendidus with ubiquitin, CgLC3 and lysosomes all decreased significantly after V. splendidus stimulation. These results indicated that CgLRSAM1 functioned as E3 ligase responsible for anti-Vibrio-associated ubiquitination and regulated the degradation of bacteria through the ubiquitination-autophagy-lysosome pathway.