American journal of physiology. Cell physiology最新文献

Osteosarcoma (OS) is a highly malignant tumor, and chemotherapy resistance is a major challenge in the treatment of this disease. This study aims to explore the role of the CLTC-VMP1 gene fusion in the mechanism of chemotherapy resistance in OS and investigate its molecular mechanisms in mediating energy metabolism reprogramming by regulating autophagy and apoptosis balance. Using single-cell transcriptome analysis, the heterogeneity of OS cells and their correlation with resistance to platinum drugs were revealed. Cisplatin-resistant cell lines were established in human OS cell lines for subsequent experiments. Based on transcriptomic analysis, the importance of VMP1 in chemotherapy resistance was confirmed. Lentiviral vectors overexpressing or interfering with VMP1 were used, and it was observed that inhibiting VMP1 could reverse cisplatin resistance, promote cell apoptosis, and inhibit autophagy, as well as mitochondrial respiration and glycolysis. Furthermore, the presence of CLTC-VMP1 gene fusion was validated, and its ability to regulate autophagy and apoptosis balance, promote mitochondrial respiration, and glycolysis was demonstrated. Mouse model experiments further confirmed the promoting effect of CLTC-VMP1 on tumor growth and chemotherapy resistance. In summary, the CLTC-VMP1 gene fusion mediates energy metabolism reprogramming by regulating autophagy and apoptosis balance, which promotes chemotherapy resistance in OS.

Studies suggest heterogeneity in cancer cachexia (CC) among models and biological sexes, yet examinations comparing models and sexes are scarce. We compared the transcriptional landscape of skeletal muscle across murine CC models and biological sexes during early and late CC. Global gene expression analyses were performed on gastrocnemius (LLC-Lewis Lung Carcinoma), quadriceps (KPC-pancreatic), and tibialis anterior (C26-colorectal and Apc^Min/+) muscles across biological sexes. Differentially expressed genes (DEGs) were identified using an adj-p-value of <0.05, followed by pathway and computational cistrome analyses. Integrating all controls, early, and late-stage of all models and sexes revealed up to 68% of DEGs and pathways were enriched at early and late CC, indicating a conserved transcriptional profile during CC development. Comparing DEGs and pathways within sexes and across models, in early-CC, the transcriptional response was highly heterogeneous. At late-stage, 11.5% of upregulated and 10% of downregulated genes were shared between models in males, while 18.9% of upregulated and 7% of downregulated DEGs were shared in females. Shared DEGs were enriched in proteasome and mitophagy/autophagy pathways (upregulated), and downregulation of energy metabolism pathways in males only. Between sexes, though proportion of shared DEGs was low (<16%), similar pathway enrichment was observed, including proteasome and mitophagy at late-stage CC. In early-CC, Osmr upregulation was the only commonality across all models and sexes, while CLOCK and ARNTL/BMAL1 were predicted transcriptional factors associated with dysregulations in all three male models. This study highlights sex and model differences in CC progression and suggests conserved transcriptional changes as potential therapeutic targets.

Purpose: This study aims to elucidate the role of Piezo1, a mechanosensitive molecule, in trabecular meshwork cells (TMCs) in the context of Primary Open Angle Glaucoma (POAG), a leading cause of irreversible visual impairment. Dysfunction of the trabecular meshwork (TM) is a key factor in the elevated intraocular pressure (IOP) observed in POAG, yet the specific mechanisms leading to TM dysfunction are not fully understood.

Methods: We performed cell stretching on human trabecular meshwork cells (HTMCs) and pharmacologically activated HTMCs with Yoda1 to study the role of Piezo1 in HTMCs. We focused on assessing cell viability, mitochondrial changes, lipid peroxidation, and the expression of ferroptosis-related targets such as acyl-CoA synthetase long-chain family member 4 (ACSL4) and glutathione peroxidase 4 (GPX4).

Results: Cell stretching induces ferroptosis in HTMCs, and this phenomenon is reversed by Piezo1 knockdown. Additionally, pharmacological activation of Piezo1 also leads to ferroptosis in HTMCs. Furthermore, inhibiting the JNK/p38 signaling pathway was found to mitigate the ferroptotic response induced by Yoda1, thereby confirming that Piezo1 induces ferroptosis in TMCs through this pathway. Notably, our experiments suggest that Yoda1 may trigger ferroptosis in the TM of mouse eyes.

Conclusions: Our findings demonstrate that the Piezo1 pathway is a crucial mediator of ferroptosis in TMCs, providing new insights into the pathogenic mechanisms of glaucoma, particularly POAG. This study highlights the potential of targeting the Piezo1 pathway as a therapeutic approach for mitigating TM dysfunction and managing POAG.

Primordial germ cells (PGCs) are the earliest progenitors of germline cells of the gonads in animals. The tissues that arise from primordial germ cells give rise to the male as well as female gametes and are thus responsible for transmitting genetic information to subsequent generations. Their development from single cells to fully formed tissues has thus been of great importance. In most higher animals, PGCs are initially specified at a site away from the gonads. They then migrate across multiple tissue contexts to reach a mesodermal mass of cells called the genital ridge, where they associate with somatic cells to form the sex-specific reproductive organs. This migratory behavior has been studied extensively to identify the various tissues PGCs interact with and how this might affect their development. A crucial point overlooked by classical studies has been the physical environment experienced by PGCs as they migrate and the mechanical challenges they might encounter. It has long been understood that migrating cells can sense and adapt to physical forces around them via a variety of mechanisms. Studies have also shown that these mechanical signals can guide stem cell fate. In this review, we summarize the mechanical microenvironment of migrating PGCs in different organisms. We describe how cells can adapt to this environment and how this adaptation can influence cell fate. We propose that mechanical signals play a crucial role in normal development of the germline and shed light on this unexplored area of developmental biology.

The voltage-gated potassium channel Kv1.3 plays a crucial role in the immune system response. In leukocytes, the channel is coexpressed with the dominant negative regulatory subunit KCNE4, which associates with Kv1.3 to trigger intracellular retention and accelerating C-type inactivation of the channel. Previous research has demonstrated that the main association between these proteins occurs through both C-termini. However, these data fail to fully elucidate the KCNE4-dependent modulation of channel kinetics. In the present study, we analyzed the contribution of each KCNE4 domain to the modulation of Kv1.3. Our results further confirmed that the C-terminus of KCNE4 is the main determinant involved in the association-triggered intracellular retention of the channel. Moreover, interactions throughout the transmembrane region were also observed. Both the C-terminus and, especially, the transmembrane domain of KCNE4 accentuated the C-type inactivation of Kv1.3. Our data provide, for the first time, the molecular effects that a KCNE peptide, such as KCNE4, exerts on a Shaker channel, such as Kv1.3. Our results pave the way for understanding the molecular mechanisms underlying potassium channel modulation and suggest that KCNE4 participates in the conformational rearrangement of the Kv1.3 architecture, altering the C-type inactivation of the channel.

Recurrent spontaneous abortion (RSA) is a significant challenge encountered by couples of reproductive ages, with inadequate trophoblast invasion identified as a primary factor in RSA pathogenesis. However, the precise molecular mechanisms through which trophoblast cells dysfunction leads to RSA remain incompletely understood. Research has highlighted the critical role of integrins in embryo implantation and development. While integrin α-3 (ITGA3) is recognized for its promotion of invasion in cancer cells, its involvement in miscarriage remains poorly characterized. This investigation initially assessed ITGA3 expression in villous tissues obtained from RSA patients and induced abortion patients. The findings demonstrated a notable reduction in ITGA3 levels in the villous tissues of RSA patients compared control group. Subsequent in vitro analyses indicated that ITGA3 knockdown inhibited the migration, invasion, and proliferation of trophoblast cells. Through RNA sequencing and subsequent experimentation, it was revealed that ITGA3 regulated ULK1-mediated autophagy to influence trophoblast cells invasion, migration, and proliferation. Furthermore, utilizing a miscarriage animal model, the diminished expression of ITGA3 and ULK1 in the placentas of RSA mice was confirmed. In conclusion, the study findings suggest that the downregulation of ITGA3 suppresses ULK1 expression, consequently impeding autophagy to initiation and impeding trophoblast cells invasion and migration, thereby contributing to the pathological progression of RSA.

Therapy resistance represents a significant challenge in oncology, occurring in various therapeutic approaches. Recently, animal models and an increasing set of clinical trials highlight the crucial impact of the gut and tumor microbiome on treatment response. The intestinal microbiome contributes to cancer initiation, progression, and formation of distant metastasis. In addition, tumor-associated microbiota is considered a critical player in influencing tumor microenvironment and regulating local immune processes. Intriguingly, numerous studies have successfully identified pathogens within the gut and tumor microbiome that might be linked to a poor response to different therapeutic modalities. The unfavorable microbial composition with the presence of specific microbes participates in cancer resistance and progression via several mechanisms, including upregulation of oncogenic pathways, macrophage polarization reprogramming, metabolism of chemotherapeutic compounds, autophagy pathway modulation, enhanced DNA damage repair, inactivation of a pro-apoptotic cascade, and bacterial secretion of extracellular vesicles, promoting the processes in the metastatic cascade. Targeted elimination of specific intratumoral bacteria appears to enhance treatment response. However, broad-spectrum antibiotic pre-treatment is mostly connected to reduced efficacy due to gut dysbiosis and lower diversity. Mounting evidence supports the potential of microbiota modulation by probiotics and fecal microbiota transplantation to improve intestinal dysbiosis and increase microbial diversity, leading to enhanced treatment efficacy while mitigating adverse effects. In this context, further research concerning the identification of clinically relevant microbiome signatures followed by microbiota-targeted strategies presents a promising approach to overcoming immunotherapy and chemotherapy resistance in refractory patients, improving their outcomes.

Perceived stress is thought to contribute to the pathogenesis of metabolic, vascular, mental, and immune diseases, with different susceptibilities in women and men. The present study investigated if and how perceived stress and/or demographic variables including sex, age, body mass index, regular prescription drugs, occasional analgesics, or dietary supplements manifested in plasma lipidomic profiles, obtained by targeted and untargeted mass spectrometry analyses. The study included 217 healthy women and 108 healthy men, aged 18-68 years, who were recruited in a 2:1 female:male ratio to account for women with/without contraceptives. As expected, dehydroepiandrosterone sulfate (DHEAS) and ceramides were higher in men than women, and DHEAS decreased with age, while ceramides increased. Contrary to expectations, neither DHEAS nor ceramides were associated with perceived stress (PSQ30 questionnaire), which was however, associated with BMI in men, but not in women. None of the lipid species or classes showed a similar "age X sex X BMI" interaction, but the endocannabinoid palmitoylethanolamide (PEA) correlated with BMI and hypertension. Independent of perceived stress, lysophosphatidylcholines (LPCs) were lower in women than men, whereas LPC metabolites, lysophosphatidic acids (LPAs), were higher in women. The LPA:LPC ratio was particularly high in women using oral contraceptives suggesting a strong hormone-induced extracellular conversion of LPCs to LPAs, which is catalyzed by the phospholipase D, autotaxin. The results reveal complex sex differences in perceived stress and lipidomic profiles, the latter being exacerbated by contraceptive use, but perceived stress and lipids were not directly correlated.

Diabetic encephalopathy (DE), a neurological complication of diabetes mellitus, has an unclear etiology. Shreds of evidence show that the Nucleotide-binding oligomerization domain-like receptor family protein 3 (NLRP3) inflammasome-induced neuroinflammation and transcription factor EB (TFEB)-mediated autophagy impairment may take part in DE development. The crosstalk between these two pathways and their contribution to DE remains to be explored. A mouse model of type 2 diabetes mellitus (T2DM) exhibiting cognitive dysfunction was created, along with high glucose (HG) cultured BV2 cells. Following, 3-methyladenine (3-MA) and rapamycin were utilized to modulate autophagy. To evaluate the potential therapeutic benefits of TFEB in DE, we overexpressed and knocked down TFEB in both mice and cells. Autophagy impairment and NLRP3 inflammasome activation were noticed in T2DM mice and HG-cultured BV2 cells. The inflammatory response caused by NLRP3 inflammasome activation was decreased by rapamycin-induced autophagy enhancement, while 3-MA treatment further deteriorated it. Nuclear translocation and expression of TFEB were hampered in HG-cultured BV2 cells and T2DM mice. Exogenous TFEB overexpression boosted NLRP3 degradation via autophagy, which in turn alleviated microglial activation as well as ameliorated cognitive deficits and neuronal damage. Additionally, TFEB knockdown exacerbated neuroinflammation by decreasing autophagy-mediated NLRP3 degradation. Our findings have unraveled the pathogenesis of a previously underappreciated disease, implying that the activation of NLRP3 inflammasome and impairment of autophagy in microglia are significant etiological factors in the DE. The TFEB-mediated autophagy pathway can reduce neuroinflammation by enhancing NLRP3 degradation. This could potentially serve as a viable and innovative treatment approach for DE.

The human colonic thiamin pyrophosphate transporter (hcTPPT) mediates the uptake of the microbiota-generated and phosphorylated form of vitamin B1 (i. e., thiamin pyrophosphate) in the large intestine. Expression of hcTPPT along the absorptive tract is restricted to the large intestine and the transporter is exclusively localized at the apical membrane domain of the polarized epithelial cells/colonocytes. Previous studies have characterized different physiological/pathophysiological aspects of the hcTPPT system, but nothing is currently known on whether the transporter has interacting partner(s) that affects its physiology/biology. We addressed this issue using a Y2H to screen a human colonic cDNA library, and have identified 3 putative interactors, namely IQGAP-2, SNX-6 and DMXL-1. Focusing on IQGAP-2 (whose expression in human colonocytes is the highest), we found (using fluorescent microscopy imaging and co-immunoprecipitation approaches) the putative interactor to co-localize with hcTPPT, and to directly interact with the transporter. Also, over-expressing IQGAP-2 in NCM460 cells and in human primary differentiated colonoid monolayers was found to lead to significant (P < 0.01) induction in TPP uptake, while it's knocking down (using gene-specific siRNAs) caused significant (P < 0.01 & < 0.05) decrease in uptake. Furthermore, over-expressing IQGAP-2 in NCM460 cells was found to lead to a significant enhancement in hcTPPT protein stability. Finally, we found the expression of IQGAP-2 to be markedly suppressed in conditions/factors that negatively impact colonic TPP uptake. These results identify the IQGAP-2 as an interacting partner with the hcTPPT in human colonocytes and show that this interaction has physiological and biological consequences.