The distribution of caveolin isoforms was previouslyevaluated in the retinas of different species, but has notyet been described in the primate retina. In this study, thedistribution of caveolins was assessed via immunochemistryusing isoform-specific antibodies in the retina of the black-and-white ruffed lemur. Here, we report the presence of avariety of caveolin isoforms in many layers of the lemurretina. As normal human retinas were not available forresearch and the retinas of primates are fairly similar tothose of humans, the lemur retina can be utilized as amodel for caveolin distribution in normal humans.
Animals ; Caveolins/*metabolism ; Immunohistochemistry ; Lemur/*metabolism ; Male ; Protein Isoforms ; Retina/*metabolism

Caveolae are specialized lipid rafts that form flask-shaped invaginations of the plasma membrane. Many researches show that caveolae are involved in cell signaling and transport. Caveolin-1 is the major coat protein essential for the formation of caveolae. Recently, several reports indicated that the other caveolae-associated proteins, Cavins, are required for caveola formation and organization. It's worth noting that Cavin-1 could cooperate with Caveolin-1 to accommodate the structural integrity and function of caveolae. Here, we reviewed that the relationship between Cavins and Caveolins and explore the role of them in regulating caveolae.
Animals ; Caveolae ; physiology ; Caveolin 1 ; metabolism ; physiology ; Caveolins ; metabolism ; physiology ; Humans ; Membrane Proteins ; metabolism ; physiology ; RNA-Binding Proteins ; metabolism ; physiology

Due to the negative autopsy and without cardiac structural abnormalities, unexpected sudden cardiac death （USCD） is always a tough issue for forensic pathological expertise. USCD may be associated with parts of fatal arrhythmic diseases. These arrhythmic diseases may be caused by disorders of cardiac ion channels or channel-related proteins. Caveolin can combine with multiple myocardial ion channel proteins through its scaffolding regions and plays an important role in maintaining the depolarization and repolarization of cardiac action potential. When the structure and function of caveolin are affected by gene mutations or abnormal protein expression, the functions of the regulated ion channels are correspondingly impaired, which leads to the occurrence of multiple channelopathies, arrhythmia or even sudden cardiac death. It is important to study the effects of caveolin on the functions of ion channels for exploring the mechanisms of malignant arrhythmia and sudden cardiac death.
Arrhythmias, Cardiac/physiopathology* ; Autopsy ; Caveolins/metabolism* ; Channelopathies/genetics* ; Death, Sudden, Cardiac/pathology* ; Forensic Pathology ; Humans ; Ion Channels/metabolism* ; Mutation ; Myocardium

OBJECTIVE: To explore the interaction between arginine functionalized hydroxyapatite (HAP/Arg) nanoparticles and endothelial cells, and to investigate mechanisms for endocytosis kinetics and endocytosis.
 METHODS: Human umbilical vein endothelial cells (HUVECs) were selected as the research model.Cellular uptake of HAP/Arg nanoparticles were observed by laser scanning confocal microscopy.Average fluorescence intensity of cells after ingestion with different concentrations of HAP/Arg nanoparticles were determined by flow cytometer and atomic force microscopy.
 RESULTS: The HAP/Arg nanoparticles with doped terbium existed in cytoplasm, and most of them distributed around the nucleus area after cellular uptake by HUVECs. Cellular uptake process of HAP/Arg nanoparticles in HUVECs was in a time and concentration dependent manner. 4 h and 50 mg/L was the best condition for uptake. HAP/Arg nanoparticles were easier to be up-taken into the cells than HAP nanoparticles without arginine functionalized.
 CONCLUSION HAP/Arg nanoparticles are internalized by HUVECs cells through an active transport and energy-dependent endocytosis process, and it is up-taken by cells mainly through caveolin-mediated endocytosis, but the clathrin-dependent endocytic pathway is also involved..
Arginine ; pharmacology ; Biological Transport, Active ; physiology ; Caveolins ; physiology ; Cells, Cultured ; Clathrin ; physiology ; Durapatite ; pharmacokinetics ; Endocytosis ; physiology ; Human Umbilical Vein Endothelial Cells ; cytology ; Humans ; Nanoparticles ; metabolism

The calcium sensing receptor (CaSR) plays an important role for sensing local changes in the extracellular calcium concentration ([Ca2+]o) in bone remodeling. Although the function of CaSR is known, the regulatory mechanism of CaSR remains controversial. We report here the regulatory effect of caveolin on CaSR function as a process of CaSR regulation by using the human osteosarcoma cell line (Saos-2). The intracellular calcium concentration ([Ca2+]i) was increased by an increment of [Ca2+]o. This [Ca2+]i increment was inhibited by the pretreatment with NPS 2390, an antagonist of CaSR. RT-PCR and Western blot analysis of Saos-2 cells revealed the presence of CaSR, caveolin (Cav)-1 and -2 in both mRNA and protein expressions, but there was no expression of Cav-3 mRNA and protein in the cells. In the isolated caveolae-rich membrane fraction from Saos-2 cells, the CaSR, Cav-1 and Cav-2 proteins were localized in same fractions (fraction number 4 and 5). The immuno-precipitation experiment using the respective antibodies showed complex formation between the CaSR and Cav-1, but no complex formation of CaSR and Cav-2. Confocal microscopy also supported the co-localization of CaSR and Cav-1 at the plasma membrane. Functionally, the [Ca2+]o- induced [Ca2+]i increment was attenuated by the introduction of Cav-1 antisense oligodeoxynucleotide (ODN). From these results, in Saos-2 cells, the function of CaSR might be regulated by binding with Cav-1. Considering the decrement of CaSR activity by antisense ODN, Cav-1 up-regulates the function of CaSR under normal physiological conditions, and it may play an important role in the diverse pathophysiological processes of bone remodeling or in the CaSR- related disorders in the body.
Bone Neoplasms ; Calcium/*metabolism ; Caveolins/*metabolism ; Cell Fractionation ; Cell Line, Tumor ; Cell Membrane/*metabolism ; Humans ; Microscopy, Confocal ; Oligoribonucleotides, Antisense/pharmacology ; Osteosarcoma ; Receptors, Calcium-Sensing/antagonists & inhibitors/*metabolism ; Research Support, Non-U.S. Gov't ; Up-Regulation

OBJECTIVETo observe the effect of naringin of Drynaria Rhizome, a Chinese medical component of Zhuanggu Jianxi Recipe (ZJR) containing serum on caveolin-p38MAPK signal factors (such as caveolin-1, p-p38, p-ATF-2, IL-1β, and TNF-α) in IL-1β induced rabbit degenerated chondrocytes, and further to explore its mechanism for protecting articular cartilages.

METHODSNaringin of Drynaria Rhizome was obtained and analyzed by HPLC-TOF/MS. Four weeks old New Zealand rabbits were killed and their bilateral knee joints were isolated aseptically. CDs were isolated and then cultured in vitro. The second generation of CDs were used for later experiment. The effect of naringin on CDs proliferation was detected by MTT assay. The effect of naringin on the expression of IL-1β-induced collagen II in CDs was detected by immunohistochemical method. The effect of naringin on caveolin-1, p-p38, and p-ATF-2 protein in IL-1β-induced CDs was detected by Western blot. The effect of naringin on mRNA expression of IL-1β and TNF-α in IL-1β-induced CDs was detected by RT-PCR.

RESULTSThe appearance time of naringin in flow graphs of naringin standard solution and ZJR containing serum was 23.5 min, and the molecular weight ranged between 581.0 and 581.5 m/z. Naringin could promote the proliferation of CDs, and inhibit the effect of IL-1β on collagen II in CDs. Compared with the model group, naringin could reduce the expression of caveolin-1, p-p38, p-ATF-2, IL-1β, and TNF-α in IL-1β induced CDs (P < 0.05), which was approximate to the level of the normal group.

CONCLUSIONSNaringin could not only promote the proliferation of CDs, but also protect IL-1β-induced CDs. Its mechanism might be associated with decreasing the expression of caveolin-1, p-p38, and p-ATF-2 proteins, inhibiting caveolin-p38MAPK signal pathway, and further reducing mRNA expression of IL-1β and TNF-α in the downstream of caveolin-p38MAPK signal pathway.

Animals ; Blotting, Western ; Cartilage, Articular ; Caveolins ; Chondrocytes ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Flavanones ; pharmacology ; Interleukin-1beta ; metabolism ; Polypodiaceae ; Rabbits ; Rhizome ; Signal Transduction ; Tumor Necrosis Factor-alpha ; metabolism ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVETo evaluate the effect of Zhuanggu Jianxi Decoction (, ZGJXD) on interleukin-1 β (IL-1 β)-induced degeneration of chondrocytes (CDs) as well as the activation of caveolin-p38 mitogen-activated protein kinase (MAPK) signal pathway, investigating the possible molecular mechanism that ZGJXD treats osteoarthritis.

METHODSSerum pharmacology was applied in the present study, where ZGJXD was orally administrated to New Zealand rabbits and then ZGJXD containing serum (ZGJXD-S) was collected for following in vitro experiments. CDs were isolated aseptically from New Zealand rabbits and then cultured in vitro. Upon IL-1 β stimulation, the degeneration of CDs was verified by inverted microscope, toluidine blue stain and type II collagen immunocytochemistry. After IL-1 β-stimulated CDs were intervened with blank control serum, ZGJXD-S, together with or without SB203580 (a specific inhibitor of p38 MAPK) for 48 h, caveolin-1 protein expression and the phosphorylation level of p38 were determined by Western blotting, and the mRNA expression of IL-1 β, tumor necrosis factor α (TNF-α), matrix metalloproteinase 3 (MMP-3) and MMP-13 were examined by real-time polymerase chain reaction.

RESULTSIL-1 β stimulation induced degeneration of CDs, increased caveolin-1 expression and p38 phosphorylation, up-regulated the mRNA level of IL-1 β, TNF-α, MMP-3 and MMP-13. However, the IL-1 β-induced activation of caveolin-p38 signaling and alteration in the expression of p38 downstream target genes were suppressed by ZGJXD-S and/or SB203580 in CDs.

CONCLUSIONZGJXD can prevent CDs degeneration via inhibition of caveolin-p38 MAPK signal pathway, which might be one of the mechanisms that ZGJXD treats osteoarthritis.

Animals ; Base Sequence ; Blotting, Western ; Caveolins ; metabolism ; Chondrocytes ; drug effects ; enzymology ; metabolism ; DNA Primers ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression Profiling ; Interleukin-1beta ; physiology ; MAP Kinase Signaling System ; Male ; RNA, Messenger ; genetics ; Rabbits ; p38 Mitogen-Activated Protein Kinases ; genetics ; metabolism

To study the influence of hypercholesterolemia with caveolin-1 on the plasmalemma of vascular endothelium, we used the methods of immunohistochemistry to detect the dynamic changes of caveolin-1 in cultured ECV-304 cells which were stimulated high cholesterol serum and the arterial endothelium of hypercholesterolemia rats. It is resulted that high cholesteorol level can upregulate the expression of caveolin-1 both in vitro and in vivo. In the initial stage of hypercholesterolemia model, the expression of caveolin-1 increased as the time of high cholesterol level added, but in the later period it was decreased slightly.
Animals ; Aorta ; pathology ; Caveolin 1 ; Caveolins ; biosynthesis ; genetics ; Cells, Cultured ; Cholesterol ; blood ; Endothelium, Vascular ; cytology ; metabolism ; Female ; Humans ; Hypercholesterolemia ; metabolism ; Male ; Rabbits ; Rats ; Rats, Sprague-Dawley ; Umbilical Veins ; cytology

The organic anion transporters (OAT) have recently been identified. Although the some transport properties of OATs in the kidney have been verified, the regulatory mechanisms for OAT's functions are still not fully understood. The rat OAT1 (rOAT1) transports a number of negatively charged organic compounds between the cells and their extracellular milieu. Caveolin (Cav) also plays a role in membrane transport. Therefore, we investigated the protein-protein interactions between rOAT1 and caveolin-2. In the rat kidney, the expressions of rOAT1 mRNA and protein were observed in both the cortex and the outer medulla. With respect to Cav-2, the expressions of mRNA and protein were observed in all portions of the kidney (cortex < outer medulla = inner medulla). The results of Western blot analysis using the isolated caveolae-enriched membrane fractions or the immunoprecipitates by respective antibodies from the rat kidney showed that rOAT1 and Cav-2 co-localized in the same fractions and they formed complexes each other. These results were confirmed by performing confocal microscopy with immunocytochemistry using the primary cultured renal proximal tubular cells. When the synthesized cRNA of rOAT1 along with the antisense oligodeoxynucleotides of Xenopus Cav-2 were co-injected into Xenopus oocytes, the [14C]p-aminohippurate and [3H]methotrexate uptake was slightly, but significantly decreased. The similar results were also observed in rOAT1 over-expressed Chinese hamster ovary cells. These findings suggest that rOAT1 and caveolin-2 are co-expressed in the plasma membrane and rOAT1's function for organic compound transport is upregulated by Cav-2 in the normal physiological condition.
Animals ; Biological Transport, Active/*physiology ; CHO Cells ; Caveolins/*metabolism ; Cell Membrane/*metabolism ; Cells, Cultured ; Hamsters ; Immunoprecipitation ; Kidney Tubules, Proximal/*metabolism ; Methotrexate/metabolism ; Microscopy, Confocal ; Oligonucleotides, Antisense/pharmacology ; Oocytes/metabolism ; Organic Anion Transport Protein 1/antagonists & inhibitors/genetics/*metabolism ; RNA, Complementary/metabolism ; RNA, Messenger/genetics/metabolism ; Rats ; Research Support, Non-U.S. Gov't ; Xenopus laevis/metabolism ; p-Aminohippuric Acid/metabolism

We investigated glucose uptake and the translocation of Akt and caveolin-3 in response to insulin in H9c2 cardiomyoblasts exposed to an experimental insulin resistance condition of 100 nM insulin in a 25 mM glucose containing media for 24 h. The cells under the insulin resistance condition exhibited a decrease in insulin-stimulated 2-deoxy[3 H]glucose uptake as compared to control cells grown in 5 mM glucose media. In addition to a reduction in insulin-induced Akt translocation to membranes, we observed a significant decrease in insulin-stimulated membrane association of phosphorylated Akt with a consequent increase of the cytosolic pool. Actin remodeling in response to insulin was also greatly retarded in the cells. When translocation of Akt and caveolin-3 to caveolae was examined, the insulin resistance condition attenuated localization of Akt and caveolin-3 to caveolae from cytosol. As a result, insulin-stimulated Akt activation in caveolae was significantly decreased. Taken together, our data indicate that the decrease of glucose uptake into the cells is related to their reduced levels of caveolin-3, Akt and phosphorylated Akt in caveolae. We conclude that the insulin resistance condition induced the retardation of their translocation to caveolae and in turn caused an attenuation in insulin signaling, namely activation of Akt in caveolae for glucose uptake into H9c2 cardiomyoblasts.
Animals ; Biological Transport ; Caveolae/drug effects/*metabolism ; Caveolins/*metabolism ; Cell Membrane/metabolism ; Cells, Cultured ; Cytosol/metabolism ; Enzyme Activation/drug effects ; Glucose/*metabolism ; Heart/embryology ; Insulin/pharmacology ; *Insulin Resistance ; Myocytes, Cardiac/drug effects/*metabolism ; Phosphorylation ; Protein Transport ; Protein-Serine-Threonine Kinases/*metabolism ; Proto-Oncogene Proteins/*metabolism ; Rats ; Research Support, Non-U.S. Gov't