Search Results (228)

Background: Previous proteomic studies provided valuable information about cataracts, but unclarified issues, such as sex and ethnicity-associated differences, remain. This study aimed to provide additional data on cataract-related proteins regarding age, sex, and cataract type. Methods: Twenty-six female and seven male Turkish cataract patients were screened for visual acuity and dysfunctional lens index. A nano-LC-MS/MS system and Progenesis QI software v3.0 were used for protein identification and quantification. The remaining data were evaluated with SPSS Version 29.0 software. Results: Proteins that showed age-associated changes were mainly involved in cytoskeletal organization. A glyoxalase enzyme, caveolin 1, and HS90B were lower, and RAB8B and ATP6V1B1 were higher in lenses in women. Proteins with lower levels in cataractous lenses than in transparent lenses included filensin and phakinin, concurrent with previous publications, and LCTL, GDI, HSPB1, and EIF4A2, not reported before. Corticonuclear cataracts constituted the only group showing depletions in putatively protective proteins, while the cortical type was the least influenced. ANXA1 and DNHD1 positively, and TCPD, SEC14L2, and PRPS1 proteins negatively correlated with visual acuity. Conclusions: This study revealed cataract-related proteins concurrent with earlier studies and new ones hitherto unreported. Despite the low number of patients investigated, the results merit further research, as these new proteins are highly likely to be involved in cataractogenesis. Full article

This study aims to enhance the dissolution rate and oral absorption of quercetin (QUR) by formulating quercetin crystalline solid dispersion (QUR-CSD). Quercetin, as a natural antioxidant, can effectively neutralize free radicals, reduce inflammatory responses, help lower the risk of cardiovascular diseases and certain cancers, and support the function of the immune system. CSDs underwent characterization through powder X-ray diffraction and scanning electron microscopy, and dissolution rates were evaluated in vitro. Oral absorption assessment was conducted using SD rats, while Caco-2 monolayer cell transmembrane (CMCT) and single pass intestinal perfusion (SPIP) were performed to assess the permeability of CSDs. QUR within the CSDs exhibited hydrogen bond interactions with P188 and PEG, displaying stronger interaction parameters (χ) of –4.0 and –6.1, respectively. The crystalline domain of QUR within Poloxamer 188 (P188) was smaller than within polyethylene glycol 8000 (PEG8000). CSDs improved the dissolution rate of QUR, with the P188-CSD slightly outperforming the PEG8000-CSD due to P188’s ability to enhance drug wettability and solubility and to maintain supersaturation. Pharmacokinetic results revealed a 3.5-fold and 25-fold increase in oral absorption for P188-CSD and PEG8000-CSD, respectively, compared to QUR. CMCT and SPIP indicated superior permeability for PEG8000-CSD, potentially attributed to caveolin-mediated PEG transmembrane transport. QUR-CSD significantly enhanced oral absorption, with PEG8000-CSD demonstrating superior efficacy. This improvement was attributed to various factors, including crystalline size reduction, drug wettability enhancement, maintenance of supersaturation by polymers, and caveolin-mediated transmembrane transport. Full article

RNF213 encodes a unique protein with AAA+ ATPase and E3 ubiquitin ligase activities that are critical for its diverse roles, which range from involvement in human vasculopathies, such as Moyamoya disease, to ubiquitination of viral and bacterial pathogens. Nevertheless, its primary functions in human signaling remain unclear due to the limited identification of direct substrates. Here, we investigated the interaction between RNF213 and caveolin-1 (Cav-1), a small scaffolding protein vital for caveolae formation and the regulation of a plethora of cellular processes. Cav-1 specifically binds within the two functional AAA+ domains of RNF213 in an ATP-dependent manner, highlighting the influence of cellular energy status on this interaction. Consequently, RNF213 ubiquitinates Cav-1 at several N-terminal lysine residues through K48 and K63 linkages, although several Moyamoya disease-associated RNF213 mutations greatly reduce this polyubiquitination. Moreover, RNF213 activity inhibits phosphorylation of a key regulatory residue of Cav-1, as RNF213 knockdown under oxidative stress markedly enhances Cav-1 Tyr14 phosphorylation and modifies nitric oxide bioavailability in endothelial cells. Collectively, our results indicate that RNF213 functions as a molecular switch modulating Cav-1 signaling based on RNF213 functionality and cellular conditions. These findings offer new insights into vascular pathogenesis and the vast signal pathways along the RNF213–Cav-1 axis. Full article

Bone marrow-derived macrophages (BMMs) exhibit dynamic behavior and functional capabilities in response to specific microenvironmental stimuli. Recent investigations have proved that BMMs play crucial roles in promoting necrotic lesion resolution. Despite substantial advancements in understanding their activation and interaction with injured livers, researchers face challenges to develop effective treatments based on manipulating BMMs function. Caveolin-1 (Cav-1) is the major structural protein on the plasma membrane. We previously reported that Cav-1 knockout (KO) mice exhibited less functional damage and necrosis in carbon tetrachloride (CCl₄)-induced liver injury. We hypothesize that the activation and recruitment of BMMs are involved in the resolution of necrotic lesions in Cav-1 KO mice. Wild-type (WT) and Cav-1 KO mice were injected with CCl₄ (10% v/v) to induce acute liver injury model. Blood samples and hepatic tissues were harvested for serum alanine transaminase (ALT) activity assessment, histopathological examination through hematoxylin–eosin (H&E) staining, and BMMs subpopulation analysis via flow cytometry. Then, primary BMMs were isolated and cultured to investigate the effect of Cav-1 on BMMs polarization, migration, and activation of STAT3 signal pathway. Validation of hepatic macrophage depletion was induced by administrating clodronate liposomes (CLs), and BMMs reconstitution was evaluated by EGFP labelled BMMs. Following this, hepatic macrophages were depleted by CLs, BMMs were isolated from Cav-1 KO, and WT mice were cultured and administrated to evaluate the protective role of Cav-1-deleted BMMs on the resolution of hepatocellular necrosis and apoptosis in acute liver injury. The BMMs ratio significantly increased from 2.12% (1D), 4.38% (1W), and 5.38% (2W) in oil control mice to 7.17%, 14.90%, and 19.30% in CCl₄-treated mice (p < 0.01 or p < 0.001). Concurrently, Cav-1 positive BMMs exhibited a marked elevation from 6.41% at 1D to 24.90% by 2W (p = 0.0228). Cav-1 KO exerted protective effects by reducing serum ALT by 26% (p = 0.0265) and necrotic areas by 28% (p = 0.0220) and enhancing BMMs infiltration by 60% (p = 0.0059). In vitro, Cav-1 KO BMMs showed a decrease in CD206 fluorescence intensity (p < 0.001), a time-dependent upregulation of arginase-1 mRNA (p < 0.05 or p < 0.01), a 1.22-fold increase in phosphorylated STAT3 (p = 0.0036), and impaired wound healing from 12 to 24 h (p < 0.001). The macrophage-depleting action in livers by CL injection persists for a minimum of 48 h. Administrated EGFP⁺ BMMs emerged as the predominant population following CL injection for a duration of 48 h. Following clodronate liposome-mediated hepatic macrophage depletion, the adoptive transfer of Cav-1 KO BMMs demonstrated therapeutic efficacy in CCl₄-induced acute liver injury. In CCl₄-induced acute liver injury, the adoptive transfer of Cav-1 KO BMMs reduced necrosis by 12.8% (p = 0.0105), apoptosis by 25.2% (p = 0.0127), doubled macrophages infiltration (p = 0.0269), and suppressed CXCL9/10 mRNA expression (p = 0.0044 or p = 0.0385). BMMs play a key role in the resolution of liver necrotic lesions in CCl₄-induced acute liver injury. Cav-1 depletion attenuates hepatocellular necrosis and apoptosis by accelerating BMMs recruitment and M2 polarization. Cav-1 in macrophages may represent a potential therapeutic target for acute liver injury. Full article

Endocytosis is a specialized transport mechanism in which the cell membrane folds inward to enclose large molecules, fluids, or particles, forming vesicles that are transported within the cell. It plays a crucial role in nutrient uptake, immune responses, and cellular communication. However, many pathogens exploit the endocytic pathway to invade and survive within host cells, allowing them to evade the immune system and establish infection. Endocytosis can be classified as clathrin-mediated (CME) or clathrin-independent (CIE), based on the mechanism of vesicle formation. Unlike CME, which involves the formation of clathrin-coated vesicles that bud from the plasma membrane, CIE does not rely on clathrin-coated vesicles. Instead, other mechanisms facilitate membrane invagination and vesicle formation. CIE encompasses a variety of pathways, including caveolin-mediated, Arf6-dependent, and flotillin-dependent pathways. In this review, we discuss key features of CIE pathways, including cargo selection, vesicle formation, routes taken by internalized cargo, and the regulatory mechanisms governing CIE. Many viruses and bacteria hijack host cell CIE mechanisms to facilitate intracellular trafficking and persistence. We also revisit the exploitation of CIE by bacterial and viral pathogens, highlighting recent discoveries in entry mechanisms, intracellular fate, and host-pathogen interactions. Understanding how pathogens manipulate CIE in host cells can inform the development of novel antimicrobial and immunomodulatory interventions, offering new avenues for disease prevention and treatment. Full article

Internalization of nanoparticles (NPs), including nanoplastic, is one of the key factors determining their toxicity. In this work, we studied the toxicity and mechanisms of the uptake of model fluorescent polystyrene NPs (PS NPs) of three different sizes (30, 50, and 100 nm) in three human cancer cells lines; two originated from gut tissue (HT-29 and Caco-2) and one originated from liver tissue (Hep G2). Toxicity was measured by Neutral Red Assay (NRU), whereas mechanisms of uptake were studied using flow cytometry and different uptake inhibitors. The toxicity of the studied NPs followed a general rule observed for NPs—the smaller ones were more toxic than the larger ones. This relationship was dose dependent; however, the overall toxicity of the studied NPs was very low, despite the significant uptake of PS NPs. Although clathrin- and caveolin-dependent uptake is generally accepted as a major route of NP uptake, the inhibition of both mechanisms did not affect PS NP uptake in the cell lines studied in this work. Further experiments revealed that the major route of PS NP uptake in these cells is a scavenger receptor-mediated uptake. Full article

To overcome the limitations associated with chemically synthesized nanoparticles in cancer therapy, researchers have increasingly focused on developing nanoparticles with superior biocompatibility and prolonged tumor retention using biosynthetic methods. In this study, we first identified the presence of calcium peroxide nanoparticles (CaO₂ NPs) in the blood of individuals who had ingested calcium gluconate. Furthermore, the dropwise addition of calcium gluconate to human serum resulted in the spontaneous self-assembly of CaO₂ NPs. Next, following tail vein injection of fluorescently labeled CaO₂ NPs into subcutaneous tumor-bearing nude mice, we observed that the nanoparticles exhibited prolonged accumulation at the tumor sites compared to other organs through visible-light imaging. Immunofluorescence staining demonstrated that CaO₂ NPs co-localized with vesicular transport-associated proteins, such as PV-1 and Caveolin-1, as well as the albumin-binding-associated protein SPARC, suggesting that their transport from tumor blood vessels to the tumor site is mediated by Caveolin-1- and SPARC-dependent active transport pathways. Additionally, the analysis of various organs in normal mice injected with CaO₂ NPs at concentrations significantly higher than the experimental dose showed no apparent organ damage. Hemolysis assays indicated that hemolysis occurred only at calcium concentrations of 300 µg/mL, whereas the experimental concentration remained well below this threshold with no detectable hemolytic activity. In a subcutaneous tumor-bearing nude mouse model, treatment with docetaxel-loaded CaO₂ NPs showed a 68.5% reduction in tumor volume compared to free docetaxel (DTX) alone. These novel biosynthetic CaO₂ NPs demonstrated excellent biocompatibility, prolonged retention at the tumor site, safety, and drug-loading capability. Full article

High-mobility group box 1 (HMGB1) is a nuclear protein that can be secreted or released into the extracellular environment during cellular stress, functioning as a damage-associated molecular pattern molecule. This study investigates the role of HMGB1 in adipocyte development and metabolism, explicitly examining its interaction with β3-adrenergic receptor-mediated lipolysis and caveolin-1 (CAV1) regulation, which may influence cardiovascular risk factors. Using 3T3-L1 preadipocytes and mouse embryonic fibroblasts, we demonstrated that HMGB1 expression increases progressively during adipogenesis, reaching peak levels in mature adipocytes. While exogenous HMGB1 treatment did not affect preadipocyte proliferation or differentiation, it inhibited lipolysis in mature adipocytes. Mechanistically, HMGB1 suppressed β3-adrenergic receptor agonist CL-316,243-induced hormone-sensitive lipase activation by reducing protein kinase A-mediated phosphorylation and attenuating extracellular signal-regulated kinase signaling without affecting upstream cyclic AMP levels. We discovered a novel regulatory mechanism wherein CAV1 physically interacts with HMGB1 in mature adipocytes, with c-Src-dependent CAV1 phosphorylation functioning as a negative regulator of HMGB1 secretion. This finding was confirmed in CAV1-deficient models, which displayed increased HMGB1 secretion and diminished lipolytic activity both in vitro and in vivo. Furthermore, administering HMGB1-neutralizing antibodies to wild-type mice enhanced fasting-induced lipolysis, establishing circulating HMGB1 as a crucial antilipolytic factor. These findings reveal HMGB1’s previously uncharacterized role in adipose tissue metabolism as a negative regulator of lipolysis through CAV1-dependent mechanisms. This work provides new insights into adipose tissue metabolism regulation and identifies potential therapeutic targets for obesity-related metabolic disorders and cardiovascular diseases. Full article

Caveolae are distinctive, flask-shaped structures within the cell membrane that play critical roles in cellular signal transduction, ion homeostasis, and mechanosensation. These structures are composed of the caveolin protein family and are enriched in cholesterol and sphingolipids, creating a unique lipid microdomain. Caveolae contribute to the functional regulation of various ion channels through both physical interactions and involvement in complex signaling networks. Ion channels localized within caveolae are involved in critical cellular processes such as the generation and propagation of action potentials, cellular responses to mechanical forces, and regulation of metabolism. Dysregulation of caveolae function has been linked to the development of various diseases, including cardiovascular disorders, neurodegenerative diseases, metabolic syndrome, and cancer. This review summarizes the ion channel function and regulation in caveolae, and their pathological implications, offering new insights into their potential as therapeutic targets for ion channel-related diseases. Full article

Pore-forming peptides are promising antimicrobial and anticancer agents due to their membrane selectivity and biodegradability. Our prior work identified peptide M159, which permeabilized synthetic phosphatidylcholine liposomes without mammalian cell toxicity. Here, we report that the D-type variant (D-M159) induces apoptosis in HeLa cells under starvation. To explore its anticancer mechanism, we analyzed D-M159 cytotoxicity, intracellular uptake, and apoptotic pathways via flow cytometry, confocal microscopy, and Western blot. Calcium dynamics and mitochondrial function were examined via specific labeling and functional assays. Results revealed that D-M159 exhibited starvation-dependent, dose-responsive cytotoxicity and triggered apoptosis in HeLa cells. Mechanistic studies indicated that D-M159 entered the cells via caveolin-dependent and caveolae-dependent endocytosis pathways and induced endoplasmic reticulum stress in HeLa cells by up-regulating proteins such as ATF6, p-IRE1, PERK, GRP78, and CHOP. Meanwhile, D-M159 promoted the expression of IP3R1, GRP75, and VDAC1, which led to mitochondrial calcium iron overload, decreased mitochondrial membrane potential, and increased reactive oxygen species (ROS) generation, thereby activating the mitochondrial apoptotic pathway and inducing the aberrant expression of Bax, Bcl-2, Caspase-9, and Caspase-3. This study showed that D-M159 synergistically induced apoptosis in starved HeLa cells through endoplasmic reticulum stress and mitochondrial dysfunction, demonstrating its potential as a novel anticancer agent. Full article

Rationale: The role of the innate immune system in idiopathic pulmonary fibrosis (IPF) remains poorly understood. However, a functional myeloid compartment is required to remove dying cells and cellular debris, as well as to mediate innate immune responses against pathogens. Aberrant macrophage activity has been described in patients with post-acute sequelae of COVID fibrosis (PASC-F), and caveolin scaffolding domain (CSD) peptides have been found to attenuate inflammation and fibrosis in mouse lung injury models. Therefore, we examined, for the first time, the effects of CSD peptide LTI-2355 on the functional and synthetic properties of human myeloid cells isolated from lung explant tissue of donor lungs as well as IPF and PASC-F lung explant tissue. Methods and Results: CD45⁺ myeloid cells isolated from lung explant tissue from IPF and PASC-F patients exhibited an impaired capacity to clear autologous dead cells and cellular debris. The uptake of pathogen-coated bioparticles was impaired in myeloid cells from both fibrotic patient groups independent of the type of pathogen, highlighting an intrinsic functional cell impairment. LTI-2355 improved the phagocytic activity of both IPF and PASC-F myeloid cells, and this improvement was paired with decreased proinflammatory and pro-fibrotic synthetic activity. LTI-2355 was also shown to primarily target CD206-expressing IPF and PASC-F myeloid cells. Conclusions: Primary myeloid cells from IPF and PASC-F patients exhibit dysfunctional phagocytic and synthetic properties that are modulated by LTI-2355. LTI-2355 treatment of IPF myeloid cells resulted in significantly reduced sCD163, IFN-α2, IFN-γ, IL-2, IL-10, IL-12p40, and MMP-1 in the cell supernatant. This study highlights an additional mechanism of action of the CSD peptide in the treatment of IPF and progressive fibrotic lung disease. Full article

Caveolae are small flask-shaped invaginations of the plasma membrane enriched in cholesterol and sphingolipids. They play a critical role in various cellular processes, including signal transduction, endocytosis, and mechanotransduction. Caveolin proteins, specifically Cav-1, Cav-2, and Cav-3, in addition to their role as structural components of caveolae, have been found to regulate the activity of signaling molecules. A growing body of research has highlighted the pivotal role of caveolae and caveolins in maintaining cellular metabolic homeostasis. Indeed, studies have demonstrated that caveolins interact with the key components of insulin signaling, glucose uptake, and lipid metabolism, thereby influencing energy production and storage. The dysfunction of caveolae or the altered expression of caveolins has been associated with metabolic disorders, including obesity, type 2 diabetes, and ocular diseases. Remarkably, mutations in caveolin genes can disrupt cellular energy balance, promote oxidative stress, and exacerbate metabolic dysregulation. This review examines current research on the molecular mechanisms through which caveolae and caveolins regulate cellular metabolism, explores their involvement in the pathogenesis of metabolic disorders, and discusses potential therapeutic strategies targeting caveolin function and the stabilization of caveolae to restore metabolic homeostasis. Full article

The effect of the gut microbiota extends beyond their habitant place from the gastrointestinal tract to distant organs, including the cardiovascular system. Research interest in the relationship between the heart and the gut microbiota has recently been emerging. The gut microbiota secretes metabolites, including Trimethylamine N-oxide (TMAO), short-chain fatty acids (SCFAs), bile acids (BAs), indole propionic acid (IPA), hydrogen sulfide (H₂S), and phenylacetylglutamine (PAGln). In this review, we explore the accumulating evidence on the role of these secreted microbiota metabolites in the pathophysiology of ischemic and non-ischemic heart failure (HF) by summarizing current knowledge from clinical studies and experimental models. Elevated TMAO contributes to non-ischemic HF through TGF-ß/Smad signaling-mediated myocardial hypertrophy and fibrosis, impairments of mitochondrial energy production, DNA methylation pattern change, and intracellular calcium transport. Also, high-level TMAO can promote ischemic HF via inflammation, histone methylation-mediated vascular fibrosis, platelet hyperactivity, and thrombosis, as well as cholesterol accumulation and the activation of MAPK signaling. Reduced SCFAs upregulate Egr-1 protein, T-cell myocardial infiltration, and HDAC 5 and 6 activities, leading to non-ischemic HF, while reactive oxygen species production and the hyperactivation of caveolin-ACE axis result in ischemic HF. An altered BAs level worsens contractility, opens mitochondrial permeability transition pores inducing apoptosis, and enhances cholesterol accumulation, eventually exacerbating ischemic and non-ischemic HF. IPA, through the inhibition of nicotinamide N-methyl transferase expression and increased nicotinamide, NAD+/NADH, and SIRT3 levels, can ameliorate non-ischemic HF; meanwhile, H₂S by suppressing Nox4 expression and mitochondrial ROS production by stimulating the PI3K/AKT pathway can also protect against non-ischemic HF. Furthermore, PAGln can affect sarcomere shortening ability and myocyte contraction. This emerging field of research opens new avenues for HF therapies by restoring gut microbiota through dietary interventions, prebiotics, probiotics, or fecal microbiota transplantation and as such normalizing circulating levels of TMAO, SCFA, BAs, IPA, H₂S, and PAGln. Full article

Neisseria meningitidis is a human-specific pathogen that colonizes the nasopharyngeal epithelium, which is populated by a dynamic microbiota that includes Lactobacillus species. Currently, little is known about the interaction between commensal lactobacilli and pathogenic Neisseria, emphasizing a need for deeper studies into the molecular interactions between the two bacteria species. This, in turn, could add clinical and therapeutic value to existing treatments against an N. meningitidis infection. In this work, we explored how lactobacilli affect the interplay between N. meningitidis and host cells. We report that Lactobacillus crispatus, but not other tested Lactobacillus species, efficiently enters pharyngeal cells via caveolin-mediated lipid raft endocytosis and simultaneously enhances the uptake of N. meningitidis, as well as uptake of other pathogenic and non-pathogenic microbes. After promoting internalization, L. crispatus then prevented N. meningitidis from being released and transcytozed from a confluent cell layer on microporous transwell membranes. Infected cells increased the level of acidic vacuoles and pathogen clearance over time, while lactobacilli survived inside the cells. Taken together, the data suggest a possible route through which the cellular uptake of lactobacilli can increase the uptake of pathogens for destruction. Full article

Background: Sorting nexin 19 (SNX19) is important in the localization and trafficking of the dopamine D₁ receptor (D₁R) to lipid raft microdomains. However, the interaction between SNX19 and the lipid raft components caveolin-1 or flotillin-1 and, in particular, their roles in the cellular endocytosis and cell membrane trafficking of the D₁R have not been determined. Methods: Caveolin-1 and flotillin-1 motifs were analyzed by in silico analysis; colocalization was observed by confocal immunofluorescence microscopy; protein-protein interaction was determined by co-immunoprecipitation. Results: In silico analysis revealed the presence of putative caveolin-1 and flotillin-1 binding motifs within SNX19. In mouse and human renal proximal tubule cells (RPTCs), SNX19 was localized mainly in lipid rafts. In mouse RPTCs transfected with wild-type (WT) Snx19, fenoldopam (FEN), a D₁-like receptor agonist, increased the colocalization of SNX19 with caveolin-1 and flotillin-1. FEN also increased the co-immunoprecipitation of SNX19 with caveolin-1 and flotillin-1, effects that were prevented by SCH39166, a D₁-like receptor antagonist. The FEN-mediated increase in the residence of SNX19 in lipid rafts and the colocalization of the D₁R with caveolin-1 and flotilin-1 were attenuated by the deletion of a caveolin-1 (YHTVNRRYREF) (ΔCav1) or a flotillin-1 (EEGPGTETETGLPVS) (ΔFlot1) binding motif. The FEN-mediated increase in intracellular cAMP production was also impaired by the deletion of either the flotillin-1 or caveolin-1 binding motif. Nocodazole, a microtubule depolymerization inhibitor, interfered with the FEN-mediated increase in the colocalization between SNX19 and D₁R. Conclusion: SNX19 contains caveolin-1 and flotillin-1 binding motifs, which play an important role in D₁R endocytosis and signaling. Full article