Cav-1 Expression Research Articles

Enhanced isradipine sensitivity in vascular smooth muscle cells due to hypoxia-induced Cav1.2 splicing and RbFox1/Fox2 downregulation.

Calcium influx via the L-type voltage-gated Cav1.2 calcium channel in smooth muscle cells regulates vascular contraction. Calcium channel blockers (CCBs) are widely used to treat hypertension by inhibiting Cav1.2 channels. Using the vascular smooth muscle cell line, A7r5 and primary culture of cerebral vascular smooth muscle cells, we found that the expression and function of Cav1.2 channels are downregulated during hypoxia. Furthermore, hypoxia induces structural changes in Cav1.2 channels via alternative splicing. The expression of exon 9* is upregulated, whereas exon 33 is downregulated. Such structural alterations of Cav1.2 channels are caused by the decreased expression of RNA-binding proteins RNA-binding protein fox-1 homolog 1 and 2 (RbFox1 and RbFox2). Overexpression of RbFox1 and RbFox2 prevents hypoxia-induced exon 9* inclusion and exon 33 exclusion. Importantly, such structural alterations of the Cav1.2 channel partly contribute to the enhanced sensitivity of Cav1.2 to isradipine (a CCB) under hypoxia. Overexpression of RbFox1 and RbFox2 successfully reduces isradipine sensitivity in hypoxic smooth muscle cells. Our results suggest a new strategy to manage ischemic diseases such as stroke and myocardial infarction.

AMPK inhibits voltage-gated calcium channel-current in rat chromaffin cells

Metabolic changes are critical in the regulation of Ca2+ influx in central and peripheral neuroendocrine cells. To study the regulation of L-type Ca2+ channels by AMPK we used biochemical reagents and ATP/glucose-concentration manipulations in rat chromaffin cells. AICAR and Compound-C, at low concentration, significantly induce changes in L-type Ca2+ channel-current amplitude and voltage dependence. Remarkably, an overlasting decrease in the channel-current density can be induced by lowering the intracellular level of ATP. Accordingly, Ca2+ channel-current density gradually diminishes by decreasing the extracellular glucose concentration. By using immunofluorescence, a decrease in the expression of CaV1.2 is observed while decreasing extracellular glucose, suggesting that AMPK reduces the number of functional Ca2+ channels into the plasma membrane. Together, these results support for the first time the dependence of metabolic changes in the maintenance of Ca2+ channel-current by AMPK. They reveal a key step in Ca2+ influx in secretory cells.

Potential neuroprotective effects of 2-hydroxypropyl-β cyclodextrin against amyloid β (1-42)-induced neurotoxicity on the rat hippocampus

The neurodegenerative mechanisms of Alzheimer’s disease (AD) are not fully understood, but it is believed that amyloid beta (Aβ) peptide causes oxidative stress, neuroinflammation, and disrupts metabotropic glutamate receptor 5 (mGluR5) signaling by interacting with cholesterol and caveolin-1 (Cav-1) in pathogenic lipid rafts. This study examined the effect of 2-hydroxypropyl-β-cyclodextrin (HP-CD) on cholesterol, oxidative stress (total oxidant status), neuroinflammation (TNF-α), and mGluR5 signaling molecules such as PKCβ1, PKCβ2, ERK1/2, CREB, BDNF, and NGF in Aβ (1-42)-induced neurotoxicity. The Sprague-Dawley rats were divided into four groups: control (saline), Aβ (1-42), HP-CD (100 mg/kg), and Aβ (1-42) + HP-CD (100 mg/kg). All groups received bilateral stereotaxic injections of Aβ (1–42) or saline into the hippocampus. After surgery, HP-CD was administered intraperitoneally (ip) for 7 days. Cholesterol, TNF-α, and TOS levels were measured in synaptosomes isolated from hippocampus tissue using spectrophotometry, fluorometry, and enzyme immunoassay, respectively. The gene expressions of Cav-1, mGluR5, PKCβ1, PKCβ2, ERK1/2, CREB, BDNF, and NGF in hippocampus tissue were evaluated using reverse transcription PCR after real-time PCR analysis. Treatment with Aβ (1-42) significantly elevated cholesterol, TOS, TNF-α, Cav-1, PKCβ2, and ERK1/2 levels. Additionally, mGluR5, CREB, and BDNF levels were shown to be lowered. HP-CD reduced cholesterol, TOS, and TNF-α levels while increasing mGluR5, CREB, and BDNF in response to Aβ (1–42) treatment. These findings indicate that HP-CD may have neuroprotective activity due to the decreased levels of cholesterol, oxidative stress, and neuroinflammation, as well as upregulated levels of mGluR5, CREB, and BDNF.

The Jiangtang Tongmai Prescription Inhibits Inflammation and Fibrosis of Lung Fibroblast Autophagy Induced by Hyperglycemia by Regulating CAV1 Expression.

The lung is one of the target organs of diabetes. This study aimed to probe the protective mechanism of Jiangtang Tongmai Prescription (JTTMP) against diabetic lung injury. JTTMP-containing serum was collected, and a high glucose and high-fat diabetic cell model was established. The cells were treated with a drug-containing serum or a CAV1-associated vector. Transfection efficiency was measured by qRT-PCR and western blot, the cell proliferative capacity was tested by CCK-8 assay, and the expression of autophagosome marker LC3B was measured by immunophluorescence assay. Expression levels of the autophagy markers LC3B, p62, and Beclin-1, and the expression levels of the fibrosis markers α-SMA, FN-1, and TGF-β1 were determined by western blot, and the levels of inflammatory factors TNF-α and IL-1β in the supernatants were assessed by ELISA. In high glucose and high fat-induced MRC-5 cells, JTTMP-containing serum impeded the abnormal cell proliferation and the expression levels of autophagy markers, fibrosis markers, as well as inflammatory factors. CAV1 expression was decreased in MRC-5 cells treated with JTTMP-containing serum. In MRC-5 cells upon transfection with the CAV1 overexpression vector and treatment with JTTMP-containing serum, increased cell proliferation, increased LC3B, p62, Beclin-1, α-SMA, FN-1, and TGF-β1, TNF-α, and IL-1β levels were found compared with cells treated with JTTMP-containing serum alone. This study suggests that JTTMP suppresses CAV1 expression to attenuate diabetic lung injury by reducing abnormal proliferation and autophagy, and reducing levels of fibrosis and inflammation.

Abstract 3132: Examining The Role Of The Lung Endothelial Cell Anti-apoptotic Protein C-iap2 In Schistosomiasis-associated Pulmonary Hypertension

Introduction: Schistosomiasis-associated Pulmonary Hypertension (Sch-PH) is the most common form of group I PH worldwide and remains with no targeted therapy. Previously, we observed that the loss of the anti-inflammatory protein caveolin-1 (Cav-1) in lung endothelial cells (EC) contributed to the survival of the abnormal EC phenotype in Sch-PH. Abnormal cell survival has been associated with some members of the inhibitor of apoptosis protein (IAP) family, but their role in Sch-PH is unknown. Hypothesis: The major etiological agent of Sch-PH, i.e., S. mansoni , may contribute to the abnormal lung EC phenotype via altered IAP family expression, specifically the inducible member c-IAP2. Methods/Methods: To test this hypothesis, we first quantified constitutive c-IAP1 and inducible c-IAP2 expression on lung samples from male and female control and pre-clinical S. mansoni egg-exposed mice (240 eggs/gram body weight intraperitoneally followed by intravenous injection of 175 eggs/gram body weight). Then, the specific contribution of EC-c-IAP2 expression to the progression of the disease was evaluated in our new mouse model ( Cdh5.CreERT2;cIAP1 -/- ,cIAP2 fl/fl - Cdh5.CreERT2;cIAP1 +/- ,cIAP2 +/fl ). EC- Cav1 -/- mice were also evaluated to test the contribution of EC-Cav-1 to lung c-IAP2 expression. Results/Discussion: Western blot and immunohistochemistry analysis revealed a reduction in c-IAP2 expression in the whole lung tissue of S. mansoni egg-exposed mice compared to controls (1.21 ± 0.12; 0.88 ± 0.06, control and egg-exposed mice respectively; p<0.05; n=6). No difference was observed in c-IAP1 expression. Preliminary data indicate that genetic ablation of c-IAP2 in EC heterozygous mice promoted a mild increase in microvascular thickness and area in Masson’s Trichrome -stained lung sections. Consistent with our previous findings, c-IAP2 expression was also significantly impaired when Cav-1 expression was absent in lung ECs, suggesting that EC-Cav-1 may contribute to reduced lung c-IAP2 expression, leading to the severe vascular remodeling that underlies the development of Sch-PH. Conclusion: Our data is uncovering whether c-IAP2 expression is a novel and specific molecular target for future therapeutic approaches against chronic Sch-PH.

Caveolin-1 frame-shift mutation induces multifunctional alterations in human fibroblasts that are exosome-mediated

Caveolins, Cav1-3, are oligomeric proteins critical for the formation of membrane caveolae that regulate cell physiology. A de novo frameshift mutation (Cav1F160X) in Cav1 (Cav1M) was described in a patient with a progeria-like phenotype, lipodystrophy, and pulmonary hypertension. We hypothesize that Cav1M presents as a dominant negative protein that perturbs cellular physiology, particularly nuclear morphology, mitochondrial function, plasma membrane structure, and exocytic behavior. Transmission electron microscopy (TEM) of patient-derived dermal fibroblasts (Cav1M) showed abnormal nuclear shape, increased rough endoplasmic reticulum, and an increased number of autophagosomes. Cav1M cells present an abnormal mitochondrial size and shape, accompanied by a reduced mitochondrial capacity for energy production detected by Seahorse real-time oximetry analysis. In addition, we observed in the patient’s fibroblasts an altered pattern of Cav1 expression and distribution, with less Cav1 in caveolae membrane fractions, together with a reduced membrane cholesterol concentration and number of caveolae. Electron paramagnetic spectroscopy shows an altered localization of proteins commonly found in caveolae fractions and increased membrane fluidity. Interestingly, Cav1M fibroblasts showed 4-fold increase in exosome secretion. Nanoparticle tracking and TEM analysis revealed a significant reduction in nanoparticle size in Cav1M-derived exosomes. Normal human dermal fibroblasts (HDF) treated to express Cav1M (Cav1M1-159) or exogenously exposed to exosomes isolated from Cav1M fibroblasts showed altered nuclear morphology, exosome secretion profile, proteomics, and miRNA analysis. Our results indicate that mutations in the C-terminus of Cav1 lead to significant cellular alterations at different levels that can lead to morpho-functional features, energetic imbalances, membrane ultrastructure abnormalities, and exosome secretion and signaling alterations. These findings suggest a novel role of Cav1 that links several aspects of cell physiology, from plasma and nuclear membrane dynamics to exocytic behavior, that have potential implications in cellular communication impacting physiology and pathophysiology. 5R01HL091071. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Quinic acid regulated TMA/TMAO-related lipid metabolism and vascular endothelial function through gut microbiota to inhibit atherosclerotic

BackgroundQuinic acid (QA) and its derivatives have good lipid-lowering and hepatoprotective functions, but their role in atherosclerosis remains unknown. This study attempted to investigate the mechanism of QA on atherogenesis in Apoe−/− mice induced by HFD.MethodsHE staining and oil red O staining were used to observe the pathology. The PCSK9, Mac-3 and SM22a expressions were detected by IHC. Cholesterol, HMGB1, TIMP-1 and CXCL13 levels were measured by biochemical and ELISA. Lipid metabolism and the HMGB1-SREBP2-SR-BI pathway were detected by PCR and WB. 16 S and metabolomics were used to detect gut microbiota and serum metabolites.ResultsQA or low-frequency ABX inhibited weight gain and aortic tissue atherogenesis in HFD-induced Apoe−/− mice. QA inhibited the increase of cholesterol, TMA, TMAO, CXCL13, TIMP-1 and HMGB1 levels in peripheral blood of Apoe−/− mice induced by HFD. Meanwhile, QA or low-frequency ABX treatment inhibited the expression of CAV-1, ABCA1, Mac-3 and SM22α, and promoted the expression of SREBP-1 and LXR in the vascular tissues of HFD-induced Apoe−/− mice. QA reduced Streptococcus_danieliae abundance, and promoted Lactobacillus_intestinalis and Ileibacterium_valens abundance in HFD-induced Apoe−/− mice. QA altered serum galactose metabolism, promoted SREBP-2 and LDLR, inhibited IDOL, FMO3 and PCSK9 expression in liver of HFD-induced Apoe−/− mice. The combined treatment of QA and low-frequency ABX regulated microbe-related Glycoursodeoxycholic acid and GLYCOCHENODEOXYCHOLATE metabolism in HFD-induced Apoe−/− mice. QA inhibited TMAO or LDL-induced HCAECs damage and HMGB1/SREBP2 axis dysfunction, which was reversed by HMGB1 overexpression.ConclusionsQA regulated the gut-liver lipid metabolism and chronic vascular inflammation of TMA/TMAO through gut microbiota to inhibit the atherogenesis in Apoe−/− mice, and the mechanism may be related to the HMGB1/SREBP2 pathway.

125 Contribution of Sensory Neuron-associated Macrophages to Neuropathic Pain via Up-regulation of Calcium Channel in C Fiber Sensory Neurons in Dorsal Root Ganglion: An Animal Model Study

INTRODUCTION: Animal models have demonstrated that sensory neuron-associated macrophages (sNAMs) play a key role in the initiation and persistence of neuropathic pain. The Cav3.2 calcium channel (Cav3.2) is also known to be involved in modulating neuropathic pain in peripheral sensory neurons. METHODS: Male Sprague-Dawley rats underwent unilateral tight ligation of the lumbar 5 spinal nerve and were divided into three groups: a control group (SHAM), a group that underwent ligation without, and with minocycline (SNL and SNL+Mino). The mechanical pain threshold of the hind paw was assessed with von-Frey filament application. Immunohistochemical staining techniques were used to evaluate the levels of sNAM, Cav3.2, and C-fiber sensory neurons with anti-Iba1, anti-Cav3.2, and IB4 antibodies, respectively. Cytokine levels were analyzed using cytokine arrays and western blotting. RESULTS: The SNL group had a significantly lower pain threshold compared to the control group (p < 0.001). In the DRG, neuropathic pain led to an accumulation of macrophages and increased their ability to attach to Cav 3.2. The expression of Cav 3.2 then triggered the activation of IB4 cells in the DRG. Additionally, cytokine array and western blot analyses revealed a higher expression rate of TNF-α in the SNL group compared to the control group (p = 0.048). Treatment with minocycline resulted in increased pain threshold, decreased number of macrophages in the DRG, and interruption of the attachment between macrophages and Cav 3.2, leading to lower expression of TNF-α. CONCLUSIONS: In conclusion, the results of this study suggest that sNAMs may play a role in the development of neuropathic pain by increasing the expression of Cav3.2 through the upregulation of TNF-α release in peripheral sensory nociceptive neurons.

Expression of caveolin 1 in oral squamous cell carcinoma.

Caveolin-1 is a surface protein that is a major structural component of caveolae, which are vesicles of the plasma membrane integral to a variety of signal transduction molecules and transport functions. Caveolin-1 is a biomarker undergoing research & studies have shown an increased expression of Cav-1 in the stepwise carcinogenesis from the normal oral mucosa, hyperplastic mucosa, dysplastic mucosa, precancerous lesions to Oral Squamous Cell Carcinoma. In the present study Correlation between Caveolin-1 expression and grade of tumor was established statistically. To study immunohistochemical expression of Caveolin-1 in Oral Squamous Cell Carcinoma. Cross sectional study carried out in a tertiary care hospital. A total of 90 cases of histopathologically diagnosed oral squamous cell carcinoma was evaluated. Grading of the cases into well, moderate and poorly differentiated carcinomas was done as per WHO guidelines . Margin and lymph node status were evaluated. Anti- Caveolin-1 antibody (E249)- Caveolae marker ab32577 was used in the dilution of 1:100. Results were expressed taking reference of the methodology used by Hung et al 2003. Statistical Package for the Social Sciences (SPSS 25.0). Correlation of tumor grade and lymph node metastasis was statistically significant p=0.0006. There was a significant statistical correlation between tumor grade and immunohistochemical expression of Caveolin-1, p- value=0.00. Correlation between Lymph node metastasis and Caveolin-1 was statistically significant, p-value=0.008. Caveolin-1 expression correlates with aggressive tumor behavior and poor prognostic outcome.

Salvianolic acid B enhances tissue repair and regeneration by regulating immune cell migration and Caveolin-1-mediated blastema formation in zebrafish

IntroductionNon-healing wounds resulting from trauma, surgery, and chronic diseases annually affect millions of individuals globally, with limited therapeutic strategies available due to the incomplete understanding of the molecular processes governing tissue repair and regeneration. Salvianolic acid B (Sal B) has shown promising bioactivities in promoting angiogenesis and inhibiting inflammation. However, its regulatory mechanisms in tissue regeneration remain unclear. PurposeThis study aims to investigate the effects of Sal B on wound healing and regeneration processes, along with its underlying molecular mechanisms, by employing zebrafish as a model organism. MethodsIn this study, we employed a multifaceted approach to evaluate the impact of Sal B on zebrafish tail fin regeneration. We utilized whole-fish immunofluorescence, TUNEL staining, mitochondrial membrane potential (MMP), and Acridine Orange (AO) probes to analyze the tissue repair and regenerative under Sal B treatment. Additionally, we utilized transgenic zebrafish strains to investigate the migration of inflammatory cells during different phases of fin regeneration. To validate the importance of Caveolin-1 (Cav1) in tissue regeneration, we delved into its functional role using molecular docking and Morpholino-based gene knockdown techniques. Additionally, we quantified Cav1 expression levels through the application of in situ hybridization. ResultsOur findings demonstrated that Sal B expedites zebrafish tail fin regeneration through a multifaceted mechanism involving the promotion of cell proliferation, suppression of apoptosis, and enhancement of MMP. Furthermore, Sal B was found to exert regulatory control over the dynamic aggregation and subsequent regression of immune cells during tissue regenerative processes. Importantly, we observed that the knockdown of Cav1 significantly compromised tissue regeneration, leading to an excessive infiltration of immune cells and increased levels of apoptosis. Moreover, the knockdown of Cav1 also affects blastema formation, a critical process influenced by Cav1 in tissue regeneration. ConclusionThe results of this study showed that Sal B facilitated tissue repair and regeneration through regulating of immune cell migration and Cav1-mediated fibroblast activation, promoting blastema formation and development. This study highlighted the potential pharmacological effects of Sal B in promoting tissue regeneration. These findings contributed to the advancement of regenerative medicine research and the development of novel therapeutic approaches for trauma.

Abstract 7080: Regulation of caveolin-1 by RAS/RAF oncogenic signaling in cancer cells

Abstract Background and Purpose: Caveolin-1 (Cav-1), a scaffolding protein implicated in cellular signaling and membrane dynamics, undergoes intricate regulation at multiple levels. Recent evidence has suggested a potential association between oncogenic mutations and alterations in Cav-1 expression. Our study aimed to comprehensively explore how RAS/RAF mutations influence Cav-1 expression in cancer cells, as well as the underlying molecular mechanisms, using tetracycline (tet)-inducible cell lines and cancer cell lines harboring endogenous BRAF or KRAS mutations. Experimental Design: We assessed the regulation of Cav-1 expression using tet-inducible cell lines with BRAFV600E, KRASG12D, or KRASG12C mutations. We measured the half-life of Cav-1 at protein levels by using cycloheximide. We monitored Cav-1 localization and degradation dynamics by SNAP-based pulse-chase assay. Additionally, we performed protein and gene expression analyses by immunoblotting and qRT-PCR, luciferase reporter assay, and immunofluorescence to dissect the impact of BRAF and KRAS mutations on Cav-1 regulation at various stages of its life cycle. Results: We found a significant downregulation of Cav-1 at both mRNA and protein levels upon induction of BRAF or KRAS mutations. The use of KRASG12C, BRAFV600E, ERK, and/or MEK inhibitors in tet-inducible cell lines rescued the effects observed upon induction. The rescue effects have also been observed in H23, MiaPaCa-2 and 8505-C cancer cell lines bearing either BRAF or KRAS mutations. Notably, BRAFV600E exhibited a more pronounced reduction in Cav-1 expression than other mutations. We observed shortened half-life of Cav-1 at protein levels after induction of RAS/RAF mutations by using cycloheximide, and SNAP-based pulse-chase. These mutations accelerated lysosomal-mediated degradation of Cav-1 as determined by immunoblotting and immunofluorescence, which was reversed by lysosomal inhibitors. Conclusions: Our study establishes a novel regulatory paradigm wherein RAS/RAF mutations exert a multi-faceted influence on Cav-1 dynamics in cancer cells. The transcriptional and translational downregulation, coupled with accelerated lysosomal degradation, collectively contributes to the decreased half-life of Cav-1 following the induction of BRAF or KRAS mutations. These findings provide insights into the intricate molecular mechanisms underpinning the dysregulation of Cav-1 in the context of RAS/RAF mutations, offering potential avenues for therapeutic interventions. Citation Format: Veronica Castro Aceituno, Tiantian Cui, Haihua Feng, Linlin Yang, Sindhu Nair, Terence M. Williams. Regulation of caveolin-1 by RAS/RAF oncogenic signaling in cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7080.

Isradipine, an L-type calcium channel blocker, attenuates cocaine effects in mice by reducing central glutamate release

Substance abuse disorder is a chronic condition for which pharmacological treatment options remain limited. L-type calcium channels (LTCC) have been implicated in drug-related plasticity and behavior. Specifically, dopaminergic neurons in the mesocorticolimbic pathway express Cav1.2 and Cav1.3 channels, which may regulate dopaminergic activity associated with reward behavior. Therefore, this study aimed to investigate the hypothesis that pre-administration of the LTCC blocker, isradipine can mitigate the effects of cocaine by modulating central glutamatergic transmission. For that, we administered isradipine at varying concentrations (1, 7.5, and 15 μg/μL) via intracerebroventricular injection in male Swiss mice. This pretreatment was carried out prior to subjecting animals to behavioral assessments to evaluate cocaine-induced locomotor sensitization and conditioned place preference (CPP). The results revealed that isradipine administered at a concentration of 1 μg/μL effectively attenuated both the sensitization and CPP induced by cocaine (15 mg/kg, via i. p.). Moreover, mice treated with 1 μg/μL of isradipine showed decreased presynaptic levels of glutamate and calcium in the cortex and hippocampus as compared to control mice following cocaine exposure. Notably, the gene expression of ionotropic glutamate receptors, AMPA, and NMDA, remained unchanged, as did the expression of Cav1.2 and Cav1.3 channels. Importantly, these findings suggest that LTCC blockage may inhibit behavioral responses to cocaine, most likely by decreasing glutamatergic input in areas related to addiction.

Mineralocorticoid Receptors in Vascular Smooth Muscle: Blood Pressure and Beyond.

After half a century of evidence suggesting the existence of mineralocorticoid receptors (MR) in the vasculature, the advent of technology to specifically knockout the MR from smooth muscle cells (SMCs) in mice has elucidated contributions of SMC-MR to cardiovascular function and disease, independent of the kidney. This review summarizes the latest understanding of the molecular mechanisms by which SMC-MR contributes to (1) regulation of vasomotor function and blood pressure to contribute to systemic and pulmonary hypertension; (2) vascular remodeling in response to hypertension, vascular injury, obesity, and aging, and the impact on vascular calcification; and (3) cardiovascular pathologies including aortic aneurysm, heart valve dysfunction, and heart failure. Data are reviewed from in vitro studies using SMCs and in vivo findings from SMC-specific MR-knockout mice that implicate target genes and signaling pathways downstream of SMC-MR. By regulating expression of the L-type calcium channel subunit Cav1.2 and angiotensin II type-1 receptor, SMC-MR contributes to myogenic tone and vasoconstriction, thereby contributing to systemic blood pressure. MR activation also promotes SMC proliferation, migration, production and degradation of extracellular matrix, and osteogenic differentiation by regulating target genes including connective tissue growth factor, osteopontin, bone morphogenetic protein 2, galectin-3, and matrix metallopeptidase-2. By these mechanisms, SMC-MR promotes disease progression in models of aging-associated vascular stiffness, vascular calcification, mitral and aortic valve disease, pulmonary hypertension, and heart failure. While rarely tested, when sexes were compared, the mechanisms of SMC-MR-mediated disease were sexually dimorphic. These advances support targeting SMC-MR-mediated mechanisms to prevent and treat diverse cardiovascular disorders.

Nutrient scavenging-fueled growth in pancreatic cancer depends on caveolae-mediated endocytosis under nutrient-deprived conditions.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by its nutrient-scavenging ability, crucial for tumor progression. Here, we investigated the roles of caveolae-mediated endocytosis (CME) in PDAC progression. Analysis of patient data across diverse datasets revealed a strong association of high caveolin-1 (Cav-1) expression with higher histologic grade, the most aggressive PDAC molecular subtypes, and worse clinical outcomes. Cav-1 loss markedly promoted longer overall and tumor-free survival in a genetically engineered mouse model. Cav-1-deficient tumor cell lines exhibited significantly reduced proliferation, particularly under low nutrient conditions. Supplementing cells with albumin rescued the growth of Cav-1-proficient PDAC cells, but not in Cav-1-deficient PDAC cells under low glutamine conditions. In addition, Cav-1 depletion led to significant metabolic defects, including decreased glycolytic and mitochondrial metabolism, and downstream protein translation signaling pathways. These findings highlight the crucial role of Cav-1 and CME in fueling pancreatic tumorigenesis, sustaining tumor growth, and promoting survival through nutrient scavenging.

Gingipains may be one of the key virulence factors of Porphyromonas gingivalis to impair cognition and enhance blood-brain barrier permeability: An animal study.

Blood-brain barrier (BBB) disorder is one of the early findings in cognitive impairments. We have recently found that Porphyromonas gingivalis bacteraemia can cause cognitive impairment and increased BBB permeability. This study aimed to find out the possible key virulence factors of P. gingivalis contributing to the pathological process. C57/BL6 mice were infected with P. gingivalis or gingipains or P. gingivalis lipopolysaccharide (P. gingivalis LPS group) by tail vein injection for 8 weeks. The cognitive behaviour changes in mice, the histopathological changes in the hippocampus and cerebral cortex, the alternations of BBB permeability, and the changes in Mfsd2a and Cav-1 levels were measured. The mechanisms of Ddx3x-induced regulation on Mfsd2a by arginine-specific gingipain A (RgpA) in BMECs were explored. P. gingivalis and gingipains significantly promoted mice cognitive impairment, pathological changes in the hippocampus and cerebral cortex, increased BBB permeability, inhibited Mfsd2a expression and up-regulated Cav-1 expression. After RgpA stimulation, the permeability of the BBB model in vitro increased, and the Ddx3x/Mfsd2a/Cav-1 regulatory axis was activated. Gingipains may be one of the key virulence factors of P. gingivalis to impair cognition and enhance BBB permeability by the Ddx3x/Mfsd2a/Cav-1 axis.

Suppression of hypoxia-induced CAV1 autophagic degradation enhances nanoalbumin-paclitaxel transcytosis and improves therapeutic activity in pancreatic cancer

Nanoalbumin-paclitaxel (nab-paclitaxel) is a standard chemotherapy for pancreatic cancer but has shown limited efficacy. However, the mechanism through which circulating nab-paclitaxel passes through the tumour vascular endothelium has not been determined. In our study, a new nonradioactive and highly sensitive method for analysing nab-paclitaxel transcytosis was established. Based on these methods, we found that hypoxia significantly enhanced the autophagic degradation of CAV1 and therefore attenuated caveolae-mediated nab-paclitaxel transcytosis across endothelial cells (ECs). In a proof-of-concept experiment, higher levels of CAV1, accompanied by lower levels of LC3B, were observed in the vascular endothelium of pancreatic cancer tissues collected from patients who showed a good response to nab-paclitaxel compared with those from patients who showed a poor response to nab-paclitaxel. Furthermore, both in vivo and in vitro studies confirmed that suppressing the autophagic degradation of CAV1 via EC-specific ATG5 knockdown or hydroxychloroquine sulfate (HCQ) treatment significantly enhanced nab-paclitaxel translocation across the endothelial barrier into pancreatic cancer cells and amplified the inhibitory effect of nab-paclitaxel on pancreatic tumour growth. The stimulation of CAV1 expression by EC-specific overexpression of exogenous CAV1 or administration of gemcitabine hydrochloride (GE) had the same effect. These results demonstrated that suppressing CAV1 autophagic degradation is a novel translatable strategy for enhancing nab-paclitaxel chemotherapeutic activity in the treatment of pancreatic cancer.

Involvement of interaction of Cav3.2 and nociceptive TRPA1 in pathological pain transmission.

T-type Ca2+ channels and TRPA1 expressed in sensory neurons are involved in pain. We previously demonstrated a functional interaction of these channels under physiological conditions. Here we investigated the possible involvement of these channels in inflammatory pain condition. We also evaluated the relationship of these channels endogenously expressed in RIN-14B, a rat pancreatic islet tumor cell line. In dorsal root ganglion (DRG) neurons innervated inflammatory side, [Ca2+]i increases induced by 15 mM KCl (15K) were enhanced in neurons responded to AITC. This enhancement was not observed in genetically TRPA1-deficient neurons. The T-type and AITC-induced currents were larger in neurons of the inflammatory side than in those of the control one. In DRGs of the inflammatory side, the protein expression of Cav3.2, but not TRPA1, was increased. In RIN-14B, 15K-induced [Ca2+]i increases were decreased by blockers of T-type Ca2+ channel and TRPA1, and by TRPA1-silencing. Immunoprecipitation suggested the coexistent of these channels in sensory neurons and RIN-14B. In mice with inflammation, mechanical hypersensitivity was suppressed by blockers of both channels. These data suggest that the interaction of Cav3.2 with TRPA1 in sensory neurons is enhanced via the augmentation of the activities of both channels under inflammatory conditions, indicating that both channels are therapeutic targets for inflammatory pain.

Sex and age affect depot expression of Ca2+ channels in rat white fat adipocytes.

White adipose tissue (WAT) requires extracellular Ca2+ influx for lipolysis, differentiation, and expansion. This partly occurs via plasma membrane Ca2+ voltage-dependent channels (CaVs). However, WFA exists in different depots whose function varies with age, sex, and location. To explore whether their CaV expression profiles also differ we used RNAseq and qPCR on gonadal, mesenteric, retroperitoneal, and inguinal subcutaneous fat depots from rats of different ages and sex. CaV expression was found dependent on age, sex, and WFA location. In the gonadal depots of both sexes a significantly lower expression of CaV1.2 and CaV1.3 was seen for adults compared to pre-pubescent juveniles. A lower level of expression was also seen for CaV3.1 in adult male but not female gonadal WFA, the latter of whose expression remained unchanged with age. Relatively little expression of CaV3.2 and 3.2 was observed. In post-pubescent inguinal subcutaneous fat, where the third and fourth mammary glands are located, CaV3.1 was decreased in males but increased in females - thus suggesting that this channel is associated with mammogenesis; however, no difference in intracellular Ca2+ levels or adipocyte size were noted. For all adult depots, CaV3.1 expression was larger in females than males - a difference not seen in pre-pubescent rats. These observations are consistent with the changes of CaV3.1 expression seen in 3T3-L1 cell differentiation and the ability of selective CaV3.1 antagonists to inhibit adipogensis. Our results show that changes in CaV expression patterns occur in fat depots related to sexual dimorphism: reproductive tracts and mammogenesis.

Caveolin-3 and Caveolin-1 Interaction Decreases Channel Dysfunction Due to Caveolin-3 Mutations.

Caveolae constitute membrane microdomains where receptors and ion channels functionally interact. Caveolin-3 (cav-3) is the key structural component of muscular caveolae. Mutations in CAV3 lead to caveolinopathies, which result in both muscular dystrophies and cardiac diseases. In cardiomyocytes, cav-1 participates with cav-3 to form caveolae; skeletal myotubes and adult skeletal fibers do not express cav-1. In the heart, the absence of cardiac alterations in the majority of cases may depend on a conserved organization of caveolae thanks to the expression of cav-1. We decided to focus on three specific cav-3 mutations (Δ62-64YTT; T78K and W101C) found in heterozygosis in patients suffering from skeletal muscle disorders. We overexpressed both the WT and mutated cav-3 together with ion channels interacting with and modulated by cav-3. Patch-clamp analysis conducted in caveolin-free cells (MEF-KO), revealed that the T78K mutant is dominant negative, causing its intracellular retention together with cav-3 WT, and inducing a significant reduction in current densities of all three ion channels tested. The other cav-3 mutations did not cause significant alterations. Mathematical modelling of the effects of cav-3 T78K would impair repolarization to levels incompatible with life. For this reason, we decided to compare the effects of this mutation in other cell lines that endogenously express cav-1 (MEF-STO and CHO cells) and to modulate cav-1 expression with an shRNA approach. In these systems, the membrane localization of cav-3 T78K was rescued in the presence of cav-1, and the current densities of hHCN4, hKv1.5 and hKir2.1 were also rescued. These results constitute the first evidence of a compensatory role of cav-1 in the heart, justifying the reduced susceptibility of this organ to caveolinopathies.

Decreased Expression of Cav-1 Is Associated with Compromised Endometrial Angiogenesis during the Implantation Window in PCOS Rats: A Prospective Randomized Laboratory-Based Study

Decreased Expression of Cav-1 Is Associated with Compromised Endometrial Angiogenesis during the Implantation Window in PCOS Rats: A Prospective Randomized Laboratory-Based Study