Caveolin-1 Research Articles

ANKRD1 activates the Wnt signaling pathway by modulating CAV3 expression and thus promotes BMSC osteogenic differentiation and bone formation in ovariectomized mice

Bone marrow-derived mesenchymal stem cells (BMSCs) are considered promising materials for treating bone diseases such as osteoporosis (OP). This research explored the functions and molecular mechanism of ankyrin repeat domain 1 (ANKRD1) in BMSC osteogenesis. An OP model in mice was established by bilateral ovariectomy. Manipulation of ANKRD1 expression in BMSCs or femurs was achieved by lentivirus infection. Increased ANKRD1 expression was observed in BMSCs during osteogenic induction. Silencing of ANKRD1 impaired the osteogenesis of BMSCs, as shown by the decreased alkaline phosphatase (ALP) activity, osteogenic gene (Runx2, Col1a1, Bglap, and Spp1) expression, and mineralized formation. ANKRD1-mediated promotion of osteogenesis was also reproduced in mouse MC3T3-E1 preosteoblastic cells. Activation of Wnt/β-catenin signaling, a well-known osteogenic stimulus, was also impaired in ANKRD1-silenced BMSCs. Overexpression of ANKRD1 resulted in the opposite effects on osteogenesis and Wnt/β-catenin signaling. Mechanistic studies revealed that ANKRD1 modulated caveolin-3 (CAV3) expression by reducing CAV3 ubiquitination, and the knockdown of CAV3 impaired the functions of ANKRD1. Additionally, a very low level of ANKRD1 was observed in the BMSCs from OP mice. Rescue of ANKRD1 significantly restored osteogenic differentiation and Wnt signaling activation in BMSCs from ovariectomized mice. The results of micro-CT, H&E staining, and IHC staining showed that ANKRD1 also promoted bone formation and Wnt activation and ameliorated pathological alterations in the femurs of OP mice. Collectively, this study demonstrated that ANKRD1 plays an important role in regulating the osteogenic differentiation of BMSCs and is a promising target for the treatment of OP and other bone diseases.

Cholesterol depletion affects caveolin-1 expression, migration and invasion of oral tongue squamous cell carcinoma cell lines

IntroductionCholesterol is a key lipid molecule within cell membranes. This is especially true in cavelolas, invaginated membrane nanodomains, which present the protein caveolin-1 (CAV-1). It is important to note that this structure is involved in many cell signalling pathways. Additionally, high cholesterol is seen in different tumor types but little is known in regards to oral tongue squamous cell carcinoma (OTSCC). The aim of this study was to evaluate the influence of cholesterol depletion on primary (SCC-25) and metastatic (HSC-3) OTSCC cell lines. Materials and methodsCell membrane fluidity, cell viability, gene and protein expression of CAV-1 and of epithelial-mesenchymal transition (EMT) markers, cell migration in Myogel and invasion-myoma assay were evaluated after cholesterol depletion with methyl-β-cyclodextrin (MβCD - 7.5, 10 or 15 mM) ResultsDecreased cell viability and increased membrane fluidity of SCC-25 cells was seen with cholesterol depletion but cell viability was less affected and there was no effect on membrane fluidity in HSC-3. Cholesterol depletion also decreased CAV-1 at 6 h but increased it after 24 h.; both epithelial and mesenchymal EMT genes were upregulated after 6 h, followed by downregulation at 24 h in SCC-25. In HSC-3, CAV-1 was downregulated, and E-cadherin gene (ECAD) was upregulated at 6 h. Only the protein β-catenin in SCC-25 was affected, and cell migration of both cell lines was decreased, affecting SCC-25 more intensely. The invasive capacity within human myoma organotypic model was increased in SCC-25 and decreased in HSC-3. ConclusionCholesterol depletion affects CAV-1 and ECAD inversely. This affect also depends on cell type since the invasive capacity was augmented in primary cells while decreased in metastatic cells.

Long-term administration of Western diet induced metabolic syndrome in mice and causes cardiac microvascular dysfunction, cardiomyocyte mitochondrial damage, and cardiac remodeling involving caveolae and caveolin-1 expression

BackgroundLong-term consumption of an excessive fat and sucrose diet (Western diet, WD) has been considered a risk factor for metabolic syndrome (MS) and cardiovascular disease. Caveolae and caveolin-1 (CAV-1) proteins are involved in lipid transport and metabolism. However, studies investigating CAV-1 expression, cardiac remodeling, and dysfunction caused by MS, are limited. This study aimed to investigate the correlation between the expression of CAV-1 and abnormal lipid accumulation in the endothelium and myocardium in WD-induced MS, and the occurrence of myocardial microvascular endothelial cell dysfunction, myocardial mitochondrial remodeling, and damage effects on cardiac remodeling and cardiac function.MethodsWe employed a long-term (7 months) WD feeding mouse model to measure the effect of MS on caveolae/vesiculo-vacuolar organelle (VVO) formation, lipid deposition, and endothelial cell dysfunction in cardiac microvascular using a transmission electron microscopy (TEM) assay. CAV-1 and endothelial nitric oxide synthase (eNOS) expression and interaction were evaluated using real-time polymerase chain reaction, Western blot, and immunostaining. Cardiac mitochondrial shape transition and damage, mitochondria-associated endoplasmic reticulum membrane (MAM) disruption, cardiac function change, caspase-mediated apoptosis pathway activation, and cardiac remodeling were examined using TEM, echocardiography, immunohistochemistry, and Western blot assay.ResultsOur study demonstrated that long-term WD feeding caused obesity and MS in mice. In mice, MS increased caveolae and VVO formation in the microvascular system and enhanced CAV-1 and lipid droplet binding affinity. In addition, MS caused a significant decrease in eNOS expression, vascular endothelial cadherin, and β-catenin interactions in cardiac microvascular endothelial cells, accompanied by impaired vascular integrity. MS-induced endothelial dysfunction caused massive lipid accumulation in the cardiomyocytes, leading to MAM disruption, mitochondrial shape transition, and damage. MS promoted brain natriuretic peptide expression and activated the caspase-dependent apoptosis pathway, leading to cardiac dysfunction in mice.ConclusionMS resulted in cardiac dysfunction, remodeling by regulating caveolae and CAV-1 expression, and endothelial dysfunction. Lipid accumulation and lipotoxicity caused MAM disruption and mitochondrial remodeling in cardiomyocytes, leading to cardiomyocyte apoptosis and cardiac dysfunction and remodeling.

Structural analysis of the P132L disease mutation in caveolin-1 reveals its role in the assembly of oligomeric complexes

Caveolin-1 (CAV1) is a membrane-sculpting protein that oligomerizes to generate flask-shaped invaginations of the plasma membrane known as caveolae. Mutations in CAV1 have been linked to multiple diseases in humans. Such mutations often interfere with oligomerization and the intracellular trafficking processes required for successful caveolae assembly, but the molecular mechanisms underlying these defects have not been structurally explained. Here, we investigate how a disease-associated mutation in one of the most highly conserved residues in CAV1, P132L, affects CAV1 structure and oligomerization. We show that P132 is positioned at a major site of protomer-protomer interactions within the CAV1 complex, providing a structural explanation for why the mutant protein fails to homo-oligomerize correctly. Using a combination of computational, structural, biochemical, and cell biological approaches, we find that despite its homo-oligomerization defects P132L is capable of forming mixed hetero-oligomeric complexes with WT CAV1 and that these complexes can be incorporated into caveolae. These findings provide insights into the fundamental mechanisms that control the formation of homo- and hetero-oligomers of caveolins that are essential for caveolae biogenesis, as well as how these processes are disrupted in human disease.

Large-scale analyses of CAV1 and CAV2 suggest their expression is higher in post-mortem ALS brain tissue and affects survival.

Introduction: Caveolin-1 and Caveolin-2 (CAV1 and CAV2) are proteins associated with intercellular neurotrophic signalling. There is converging evidence that CAV1 and CAV2 (CAV1/2) genes have a role in amyotrophic lateral sclerosis (ALS). Disease-associated variants have been identified within CAV1/2 enhancers, which reduce gene expression and lead to disruption of membrane lipid rafts. Methods: Using large ALS whole-genome sequencing and post-mortem RNA sequencing datasets (5,987 and 365 tissue samples, respectively), and iPSC-derived motor neurons from 55 individuals, we investigated the role of CAV1/2 expression and enhancer variants in the ALS phenotype. Results: We report a differential expression analysis between ALS cases and controls for CAV1 and CAV2 genes across various post-mortem brain tissues and three independent datasets. CAV1 and CAV2 expression was consistently higher in ALS patients compared to controls, with significant results across the primary motor cortex, lateral motor cortex, and cerebellum. We also identify increased survival among carriers of CAV1/2 enhancer mutations compared to non-carriers within Project MinE and slower progression as measured by the ALSFRS. Carriers showed a median increase in survival of 345 days. Discussion: These results add to an increasing body of evidence linking CAV1 and CAV2 genes to ALS. We propose that carriers of CAV1/2 enhancer mutations may be conceptualised as an ALS subtype who present a less severe ALS phenotype with a longer survival duration and slower progression. Upregulation of CAV1/2 genes in ALS cases may indicate a causal pathway or a compensatory mechanism. Given prior research supporting the beneficial role of CAV1/2 expression in ALS patients, we consider a compensatory mechanism to better fit the available evidence, although further investigation into the biological pathways associated with CAV1/2 is needed to support this conclusion.

Differential Expression of Caveolin-3, Suppression of Tumorigenicity 2, and Growth Differentiation Factor-15 Genes and Their Association with Acute Myocardial Infarction: A Cross-Sectional Study in a Multi-Specialty Hospital in Tamil Nadu

Background: Acute myocardial infarction (AMI) is one of the world's leading causes of cardiovascular death. Recent studies have reported the influence of the genes caveolin-3 (CAV3), suppression of tumorigenicity 2, and growth differentiating factor-15 in cardiovascular diseases, especially myocardial infarction, but their role and function remain unclear. Hence, this study was designed to evaluate the expression levels of these three genes in AMI and understanding the role of CAV-3 in the pathogenesis of AMI. Methods and Results: Blood samples were collected from 50 AMI patients and 50 non-AMI controls in this cross-sectional study. Relative expression levels of the three genes were performed using real-time PCR. Bioinformatics tools were used for functional gene enrichment and protein-protein interactions. CAV-3 was significantly upregulated among AMI patients compared to controls. In silico analyses identified CAV-3 as playing critical roles in smooth muscle contraction, cardiac conduction, and calcium-mediated transport via binding with essential proteins including dysferlin and annexins Conclusion: This study is a first of its kind, reporting an upregulation of CAV-3 in AMI patients. The expression of all three genes significantly influenced the systolic function of the heart in AMI patients. A more in-depth understanding of CAV-3 in the pathophysiology of AMI is essential and it may prove to be a novel.

ANGPT2/CAV1 regulates albumin transcytosis of glomerular endothelial cells under high glucose exposure and is impaired by losartan

BackgroundMicroalbuminuria is a common clinical symptom that manifests in the early stages of diabetic kidney disease (DKD) and is also the main feature of glomerular endothelial cells (GECs) injury. There is increasing evidence that the transcytosis of albumin across GECs is closely related to the formation of albuminuria. Our previous studies have shown that angiopoietin 2 (ANGPT2) can inhibit albumin transcytosis across renal tubular epithelial cells by activating caveolin 1 (CAV1) phosphorylation during high glucose (HG) exposure. The role of ANGPT2 in albumin transcytosis across GECs remains unclear. Losartan significantly reduces albuminuria, but the mechanism has not been clarified. MethodsWe established an in vitro albumin transcytosis model to investigate the change in albumin transcytosis across human renal glomerular endothelial cells (hrGECs) under normal glucose (NG), high glucose (HG) and losartan intervention. We knocked down ANGPT2 and CAV1 to evaluate their roles in albumin transcytosis across hrGECs and verified the relationship between them. In vivo, DKD mouse models were established and treated with different doses of losartan. Immunohistochemistry and Western blot were used to detect the expression of ANGPT2 and CAV1. ResultsIn vitro, the transcytosis of albumin across hrGECs was significantly increased under high glucose stimulation, and losartan inhibited this process. The expression of ANGPT2 and CAV1 were both increased in hrGECs under HG conditions and losartan intervention reduced the expression of them. Moreover, ANGPT2 downregulation reduced albumin transcytosis in hrGECs by regulating CAV1 expression. In vivo, the expression of ANGPT2 and CAV1 in the glomerulus was both increased significantly in DKD mice. Compared with DKD mice, losartan treatment reduced albuminuria and decreased the expression of ANGPT2 and CAV1 in a dose-dependent manner. ConclusionsANGPT2 exacerbated albumin transcytosis across GECs by increasing CAV1 expression during HG exposure, thereby increasing albuminuria. Losartan reduces albumin transcytosis and albuminuria formation in DKD by inhibiting the upregulation of ANGPT2 under HG conditions. Our findings suggest that ANGPT2 and CAV1 may be novel therapeutic targets for diabetic albuminuria. In addition, we provide new evidence to elaborate on the mechanism of losartan in the development of DKD.

Epidermal growth factor receptor inhibition prevents vascular calcifying extracellular vesicle biogenesis.

Chronic kidney disease (CKD) increases the risk of cardiovascular disease, including vascular calcification, leading to higher mortality. The release of calcifying extracellular vesicles (EVs) by vascular smooth muscle cells (VSMCs) promotes ectopic mineralization of vessel walls. Caveolin-1 (CAV1), a structural protein in the plasma membrane, plays a major role in calcifying EV biogenesis in VSMCs. Epidermal growth factor receptor (EGFR) colocalizes with and influences the intracellular trafficking of CAV1. Using a diet-induced mouse model of CKD followed by a high-phosphate diet to promote vascular calcification, we assessed the potential of EGFR inhibition to prevent vascular calcification. Furthermore, we computationally analyzed 7,651 individuals in the Multi-Ethnic Study of Atherosclerosis (MESA) and Framingham cohorts to assess potential correlations between coronary artery calcium and single-nucleotide polymorphisms (SNPs) associated with elevated serum levels of EGFR. Mice with CKD developed widespread vascular calcification, associated with increased serum levels of EGFR. In both the CKD mice and human VSMC culture, EGFR inhibition significantly reduced vascular calcification by mitigating the release of CAV1-positive calcifying EVs. EGFR inhibition also increased bone mineral density in CKD mice. Individuals in the MESA and Framingham cohorts with SNPs associated with increased serum EGFR exhibit elevated coronary artery calcium. Given that EGFR inhibitors exhibit clinical safety and efficacy in other pathologies, the current data suggest that EGFR may represent an ideal target to prevent pathological vascular calcification in CKD.NEW & NOTEWORTHY Here, we investigate the potential of epidermal growth factor receptor (EGFR) inhibition to prevent vascular calcification, a leading indicator of and contributor to cardiovascular morbidity and mortality. EGFR interacts and affects the trafficking of the plasma membrane scaffolding protein caveolin-1. Previous studies reported a key role for caveolin-1 in the development of specialized extracellular vesicles that mediate vascular calcification; however, no role of EGFR has been reported. We demonstrated that EGFR inhibition modulates caveolin-1 trafficking and hinders calcifying extracellular vesicle formation, which prevents vascular calcification. Given that EGFR inhibitors are clinically approved for other indications, this may represent a novel therapeutic strategy for vascular calcification.

Mechanically conditioned multilayered angle-ply collagen scaffolds promote annulus fibrosus regeneration

Annulus fibrosus (AF) injury, as a result of intervertebral disk degeneration (IVDD) or herniation, is very difficult to heal due to its avascular characteristics. Tissue engineering strategies have become increasingly promising to treat IVDD. However, in light of the fact that AF displays an anisotropic microstructure that results in gradient mechanical properties, fabrication of tissue engineered AF remains challenging. In this study, we fabricated micropatterned collagen scaffolds with angle-ply structure mimicking the microstructural features of AF. Following that, we cultured bone marrow mesenchymal stromal cells (BMSCs) in the scaffolds and applied cyclic stretching to them to mechanically stimulate the cells. We found that aligned cells under mechanical loading showed elevated expression of matrix anabolism-related genes and proteins. Further studies indicated that Caveolin-1 (CAV1) might mediate the nuclear translocation of Yes-associated protein (YAP) in response to external mechanical cues of microgroove-patterned membranes and mechanical loading. Micropatterned collagen membranes, with cells aligning at ±30° along the longitudinal dimension, were rolled up together to form an angle-ply and multilayered tissue. After being implanted into the caudal vertebra in a rat model for 4 weeks, biomimetic tissues showed improved restoration of the disk. In general, our biomimetic collagen membranes exhibit great potential in terms of AF regeneration, with AF-like heterogeneous microstructures that satisfy the biomechanical property of the native disk.

Template-free prediction of a new monotopic membrane protein fold and oligomeric assembly by AlphaFold2.

AlphaFold2 (AF2) has revolutionized the field of protein structural prediction. Here, we test its ability to predict the tertiary and quaternary structure of a previously undescribed scaffold with new folds and unusual architecture, the monotopic membrane protein caveolin-1 (CAV1). We recently found that CAV1 can assemble a disc-shaped structure composed of 11 symmetrically arranged CAV1 protomers, each of which assumes an identical new fold, that also contains the largest parallel β-barrel known to exist in nature. As this novel fold and assembly was not part of the PDB when AF2 was trained, it presents a blind and challenging test case for the algorithm. AF2 predicts the fold of the protomer despite CAV1's lack of structural similarity to other proteins in the PDB. It also assembles multiple copies of CAV1 into disc-shaped complexes similar in overall organization to those observed experimentally, and predicts several interfaces between protomers accurately at atomic-detail including helix-helix interactions and interactions between conserved residues in loops that stabilize the outer rim of the complex. Interestingly, AF2 predicts additional closed disc structures containing between 7 and 15 CAV1 protomers. However, some of these multimers are energetically strained compared to the experimental structure, especially the parallel β-barrel located in the center of the CAV1 complex. These findings highlight the ability of AF2 to correctly predict new protein folds and assemblies at a granular level, identify important protein interaction interfaces, and predict the overall organization of homo-oligomeric assemblies, while missing some elements of higher order complexes. This work posits a new direction for the continued development of AF2 and other deep learning protein structure prediction approaches.

Ion channel chameleons: Switching ion selectivity by alternative splicing

Voltage-gated sodium and calcium channels are distinct, evolutionarily related ion channels that achieve remarkable ion selectivity despite sharing an overall similar structure. Classical studies have shown that ion selectivity is determined by specific binding of ions to the channel pore, enabled by signature amino acid sequences within the selectivity filter (SF). By studying ancestral channels in the pond snail (Lymnaea stagnalis), Guan etal. showed in a recent JBC article that this well-established mechanism can be tuned by alternative splicing, allowing a single CaV3 gene to encode both a Ca2+-permeable and an Na+-permeable channel depending on the cellular context. These findings shed light on mechanisms that tune ion selectivity in physiology and on the evolutionary basis of ion selectivity.

CAV1 Impacts the Tumor Immune Microenvironment and Has Potential Value of Predicting Response to Immunotherapy in Esophageal Cancer

Caveolin-1 (CAV1) is one of the members of the caveolae, and the role of CAV1 in esophageal cancer (ESCA) is not completely clear. In this study, we found that expression of CAV1 was downregulated in ESCA in The Cancer Genome Atlas and the Genotype-Tissue Expression (GTEx) database and we also use immunohistochemistry of tissue microarray for verification. Then, we used bioinformatics methods to investigate the prognostic value of CAV1, influence on immune cell infiltration in tumor microenvironment (TME) and responding to immunotherapy in ESCA. Our result indicated that CAV1 designs an inflamed TME in ESCA based on the evidence that CAV1 positively correlated with immunomodulators, immune score, stomal score, cancer immunity cycles, tumor-infiltrating immune cells, T cell inflamed score, and immune checkpoints. Immunophenoscore, Tumor Immune Dysfunction and Exclusion algorithms, and the mutation analysis show that the downregulated CAV1 expression indicated higher tumor mutation burden and higher rate of response to immune checkpoint inhibitors (ICIs) in the low-expression group. In a word, our study demonstrated the impact of CAV1 to the TME in ESCA and it may be a new target for ESCA immunotherapy. In addition, the expression of CAV1 can predict the clinical response to ICIs, which may provide clinical treatment guidance.

Caveolin-1 ameliorates acetaminophen-aggravated inflammatory damage and lipid deposition in non-alcoholic fatty liver disease via the ROS/TXNIP/NLRP3 pathway.

The overuse of acetaminophen (APAP) may cause more severe hepatotoxicity in patients with non-alcoholic fatty liver disease (NAFLD). Caveolin-1 (CAV1), is an essential regulator of metabolic function, which can alleviate liver damage by scavenging reactive oxygen species (ROS). Evidence suggests that the NOD-like receptor family pyrin domain-containing 3 (NLRP3) -mediated pyroptosis is involved in the development of NAFLD. Moreover, thioredoxin-interactive protein (TXNIP) activation is a key event linking ROS to NLRP3 inflammasome. However, whether CAV1 alleviates APAP-aggravated hepatotoxicity in NAFLD via the ROS/TXNIP/NLRP3 pathway remains unclear. An in vivo fatty liver model was established by feeding mice a high-fat diet for 56days. Additionally, using in vitro approach, AML-12 cells were incubated with free fatty acids for 48h and APAP was added during the last 24h. We found that the overuse of APAP in NAFLD not only induced oxidative stress, but also increased TXNIP expression, NLRP3-mediated pyroptosis, and lipid deposition. In addition to inhibiting ROS generation and lipid deposition, overexpression of CAV1 reduced the elevated levels of TXNIP expression and NLRP3-mediated pyroptosis. However, the effect of CAV1 on TXNIP expression, NLRP3-mediated pyroptosis, and lipid deposition was reversed by CAV1 small interfering RNA (siRNA) intervention. Finally, N-acetyl cysteine (NAC) treatment reduced CAV1 siRNA-mediated changes in TXNIP expression and NLRP3-mediated pyroptosis levels. These results demonstrate that the inhibitory effect of CAV1 on NLRP3-mediated pyroptosis may be mediated through the ROS/TXNIP axis. Moreover, the current study provides novel mechanistic insights into the protective effects of CAV1 on APAP-aggravated hepatotoxicity in NAFLD.

Bioinformatics analysis identifies key genes of prognostic value in lung cancer

Lung cancer is the most common human malignancy worldwide and can be divided into different types of carcinomas depending on their pathological features. Advances in medical science and technology have led to the identification of some lung cancer-related marker genes, including EGFR (epidermal growth factor receptor), BRAF (B-Raf proto-oncogene), RAS (RAS proto-oncogene, GTPase) and HER2 (human epidermal growth factor receptor 2). However, the underlying biomarker and key genes associated with different types of lung cancer are still poorly understood. In this study, we analyzed a GEO (Gene Expression Omnibus) dataset and identified 28 upregulated intersection DEGs (different expression genes) and 125 downregulated intersection DEGs among AC (adenocarcinoma), PTC (primary typical carcinoid), PLCC (primary large cell carcinoma), PLCNC (primary large cell lung carcinoma) and PSCLC (primary small cell lung carcinoma). Through PPI (protein-protein interaction) network analysis, we identified 14 genes among the DEGs, namely MFAP4 (microfibril-associated protein 4), PDZD2 (PDZ domain containing 2), FBLN1 (fibulin 1), FBLN5 (fibulin 5), EFEMP1 (EGF containing fibulin extracellular matrix protein 1), KDR (kinase insert domain receptor), S1PR1 (sphingosine-1-phosphate receptor 1), CAV1 (caveolin 1), GRK5 (G protein-coupled receptor kinase 5), EDNRA (endothelin receptor type A), EDNRB (endothelin receptor type B), CALCRL (calcitonin receptor-like receptor), PTGER4 (prostaglandin E receptor 4), and ADRB1 (adrenoceptor beta 1), which were found to be downregulated in different subtypes of lung cancer and associated with poor survival outcomes. In addition, most of the screened DEGs demonstrated good predictive ability in LUAD (lung adenocarcinoma) and LUSC (lung squamous cell carcinoma). Among them, MFAP4 was found to promote cell proliferation while also suppressing cell migration and angiogenesis. In summary, we propose MFAP4, PDZD2, FBLN1, FBLN5, EFEMP1, KDR, S1PR1, CAV1, GRK5, EDNRA, EDNRB, CALCRL, PTGER4 and ADRB1 as potential prognostic markers in lung cancer patients.

CAVIN2/SDPR Functioned as a Tumor Suppressor in Lung Adenocarcinoma from Systematic Analysis of Caveolae-Related Genes and Experimental Validation.

Background: Caveolae-Related Genes include caveolins and cavins, which are the main component of the fossa and, play important roles in a variety of physiological and pathological processes. Although increasing evidence indicated that caveolins (CAVs) and cavins (CAVINs) are involved in carcinogenesis and progression, their clinical significance and biological function in lung cancer are still limited. Methods: We investigated the expression of CAVs and CAVINs at transcriptional levels using Oncomine and Gene Expression Profiling Interactive Analysis. The protein and mRNA expression levels of CAVs and CAVINs were determined by the human protein atlas website and our surgically resected samples, respectively. The clinical value of prognostic prediction based on the expression of CAVs and CAVINs was also assessed. cBioPortal, GeneMANIA and STRING were used to analyze the molecular characteristics of CAVs and CAVINs in lung adenocarcinoma (LUAD) comprehensively. Finally, we investigated the effect of CAVIN2/SDPR (serum deprivation protein response) on LUAD cells with biological experiments in vitro. Results: The expression of CAV1/2 and CAVIN1/2/3 were significantly downregulated in LUAD and lung squamous cell carcinoma (LUSC). The patients with high expression of CAV1, CAV2, CAV3, CAVIN1 and CAVIN2/SDPR were tightly correlated with a better prognosis in LUAD, while no statistical significances in LUSC. Further, our results found that CAVIN2/SDPR can be identified as a prognostic biomarker independent of other CAVINs in patients with LUAD. Mechanically, the overexpression of CAVIN2/SDPR inhibited cell proliferation and migration owing to the cell apoptosis induction and cell cycle arrest at S phase in LUAD cells. Conclusions: CAVIN2/SDPR functioned as a tumor suppressor, and was able to serve as prognostic biomarkers in precision medicine of LUAD. Mechanically, overexpression of CAVIN2/SDPR inhibited cell proliferation by inducing cell apoptosis and S phase arrest in LUAD cells.

BST2 induced macrophage M2 polarization to promote the progression of colorectal cancer.

Background: Tumor-associated macrophages (TAMs) are one of the most prominent tumor-infiltrating immune cells in the tumor microenvironment (TME) of CRC and play a vital role in the progression of CRC. BST2 was predicted to be associated with the infiltration of TAMs. However, its potential function by which CRC cells and TAMs interact with each other still needs further investigation. Methods: The target genes in CRC were selected by bioinformatics screening. The level of bone marrow stromal cell antigen 2 (BST2) in CRC cells and tissues was determined by qRT‒PCR, Western blotting, and immunohistochemistry staining. In vitro and in vivo assays were applied to clarify the function of BST2. Results: In this study, according to bioinformatics analysis, a nomogram based on the risk score (constructed by BST2 and CAV1 (caveolin-1)) and clinical features was built and displayed satisfactory prognostic value. Upregulated BST2 was significantly related to Braf mutation, dMMR/MSI-H, CMS1 subtype, and immune response and was a potential biomarker for predicting immune checkpoint blockade therapy. Silencing BST2 in CRC obviously restrained CRC progression and M2 TAM polarization. The infiltration of TAMs was positively correlated with the high expression of BST2, and depletion of TAMs alleviated the protumoural effect of BST2 in CRC in vivo. In vitro experiments revealed that a reduction in BST2 in CRC inhibited CRC proliferation and migration and also M2 polarization. Conclusion: These findings indicated that BST2 played a vital role in CRC progression and might be a predictable marker for immunotherapy.

Caveolin-1 alleviates acetaminophen-induced vascular oxidative stress and inflammation in non-alcoholic fatty liver disease

Acetaminophen (APAP) is one of the most widely used drugs in the world. The literature shows that excessive or long-term use of APAP can lead to increased cardiovascular dysfunction. An acute increase in angiotensin Ⅱ (Ang Ⅱ) caused by APAP use in fatty liver disease may increase the risk and severity of vascular injury. However, the underlying mechanism remains unclear. Caveolin-1 (CAV1) is a broad-spectrum kinase inhibitor that significantly determines endothelial function. This study aimed to observe the effects of APAP on the vasculature in non-alcoholic fatty liver disease (NAFLD) and to determine whether CAV1 could alleviate vascular oxidative stress and inflammation by targeting Ang Ⅱ or its downstream pathways. In this study, 7-week-old C57BL/6 male mice (18–20 g) were administered APAP by gavage after eight weeks of a high-fat diet. Any resulting vascular oxidative stress and inflammation were assessed. Levels of Ang Ⅱ, CAV1, and other related proteins were measured using ELISA and western blotting. In APAP-treated NAFLD mice, CAV1 expression was downregulated and Ang Ⅱ expression was upregulated compared to normal APAP-treated mice. In vitro, HUVECs were incubated with Ang Ⅱ (300 nM) for 48 h. Overexpression of CAV1 in HUVECs attenuated Ang Ⅱ-induced oxidative stress and inflammation and downregulated the expression of Protein kinase C (PKC) and p-P38/P38. After intervention with CAV1-siRNA, immunofluorescence results showed that the fluorescence intensity of PKC on mitochondria was further increased, and flow cytometry results showed that the mitochondrial membrane potential increased. PKC inhibitors alleviated Ang Ⅱ-induced endothelial injury. In conclusion, our findings confirmed that CAV1 exerts a protective effect against vascular injury by inhibiting oxidative stress and inflammation through the PKC/MAPK pathway. Therefore, restoration of CAV1 may have clinical benefits in reducing APAP-induced vascular damage in NAFLD patients.

Berplatin: A Conjugate of Berberine and Cisplatin Serving as a Potent Antitumor Agent with Distinctive Tumor Cell Uptake and Minimal Side Effects

AbstractDesign of Pt(IV) prodrugs with biologically active axial ligands is an excellent approach to overcome the disadvantages (nonspecific killing, side effects, and drug resistance) of conventional first‐line Pt(II)‐based chemotherapeutic drugs, such as cisplatin, carboplatin and oxaliplatin. The selection of ideal axial ligands is essential for the success of Pt(IV) drugs. Previously, that berberine exhibits great superiority in tumor selectivity is found with uncovered mechanisms. In this study, that berberine is specifically internalized and accumulated in tumors but not normal cells through endocytosis pathways is first disclosed. Therefore a new Pt(IV) prodrug of cisplatin bearing berberine as an axial ligand, named berplatin, is designed and synthesized. Different from cisplatin, berplatin can be effectively and selectively internalized into cancer cells, through macropinocytosis and caveolin‐1 (CAV‐1)‐dependent active endocytosis, and cleaved in intracellular reductive environments to generate cisplatin and berberine, which synergistically induces substantial DNA breaking, apoptosis and cell cycle arrest in both cisplatin‐sensitive and ‐resistant cancer cells. In vivo, berplatin manifests much higher antitumor activity and undetectable side effects compared to cisplatin. This study demonstrates that berplatin can serve as a potent Pt(IV) prodrug for the treatment of cisplatin‐sensitive and ‐resistant cancers with active uptake, excellent specificity, and minimal side effects.

Caveolin-1 rs1997623 Single Nucleotide Polymorphism Creates a New Binding Site for the Early B-Cell Factor 1 That Instigates Adipose Tissue CAV1 Protein Overexpression.

Caveolin-1 (CAV1) is implicated in the pathophysiology of diabetes and obesity. Previously, we demonstrated an association between the CAV1 rs1997623 C > A variant and metabolic syndrome (MetS). Here, we decipher the functional role of rs1997623 in CAV1 gene regulation. A cohort of 38 patients participated in this study. The quantitative MetS scores (siMS) of the participants were computed. CAV1 transcript and protein expression were tested in subcutaneous adipose tissue using RT-PCR and immunohistochemistry. Chromatin immunoprecipitation assays were performed using primary preadipocytes isolated from individuals with different CAV1 rs1997623 genotypes (AA, AC, and CC). The regulatory region flanking the variant was cloned into a luciferase reporter plasmid and expressed in human preadipocytes. Additional knockdown and overexpression assays were carried out. We show a significant correlation between siMS and CAV1 transcript levels and protein levels in human adipose tissue collected from an Arab cohort. We found that the CAV1 rs1997623 A allele generates a transcriptionally active locus and a new transcription factor binding site for early B-cell factor 1 (EBF1), which enhanced CAV1 expression. Our in vivo and in vitro combined study implicates, for the first time, EBF1 in regulating CAV1 expression in individuals harboring the rs1997623 C > A variant.

Involvement of caveolin-1 in skin diseases.

The skin is the outermost layer and largest organ in the human body. Since the skin interfaces with the environment, it has a variety of roles, including providing a protective barrier against external factors, regulating body temperature, and retaining water in the body. It is also involved in the immune system, interacting with immune cells residing in the dermis. Caveolin-1 (CAV-1) is essential for caveolae formation and has multiple functions including endocytosis, lipid homeostasis, and signal transduction. CAV-1 is known to interact with a variety of signaling molecules and receptors and may influence cell proliferation and migration. Several skin-related disorders, especially those of the inflammatory or hyperproliferative type such as skin cancers, psoriasis, fibrosis, and wound healing, are reported to be associated with aberrant CAV-1 expression. In this review, we have explored CAV-1 involvement in skin physiology and skin diseases.