Cx37 Gene Research Articles

Effect of Cyclic Adenosine Monophosphate on Connexin 37 Expression in Sheep Cumulus-Oocyte Complexes.

Gap junctional connection (GJC) in the cumulus-oocyte complex (COC) provides necessary support for message communication and nutrient transmission required for mammalian oocyte maturation. Cyclic adenosine monophosphate (cAMP) is not only a prerequisite for regulating oocyte meiosis, but also the key intercellular factor for affecting GJC function in COCs. However, there are no reports on whether cAMP regulates connexin 37 (Cx37) expression, one of the main connexin proteins, in sheep COCs. In this study, the expression of Cx37 protein and gene in immature sheep COC was detected using immunohistochemistry and PCR. Subsequently, the effect of cAMP on Cx37 expression in sheep COCs cultured in a gonadotropin-free culture system for 10 min or 60 min was evaluated using competitive ELISA, real-time fluorescent quantitative PCR (RT-qPCR), and Western blot. The results showed that the Cx37 protein was present in sheep oocytes and cumulus cells; the same results were found with respect to GJA4 gene expression. In the gonadotropin-free culture system, compared to the control, significantly higher levels of cAMP as well as Cx37 gene and protein expression were found in sheep COCs following treatment in vitro with Forskolin and IBMX (100 μM and 500 μM)) for 10 min (p < 0.05). Compared to the controls (at 10 or 60 min), cAMP levels in sheep COCs were significantly elevated as a result of Forskolin and IBMX treatment (p < 0.05). Following culturing in vitro for 10 min or 60 min, Forskolin and IBMX treatment can significantly promote Cx37 expression in sheep COCs (p < 0.05), a phenomenon which can be counteracted when the culture media is supplemented with RP-cAMP, a cAMP-specific competitive inhibitor operating through suppression of the protein kinase A (PKA). In summary, this study reports the preliminary regulatory mechanism of cAMP involved in Cx37 expression for the first time, and provides a novel explanation for the interaction between cAMP and GJC communication during sheep COC culturing in vitro.

The impact of duration and control of type 1 diabetes mellitus on microvascular function is strongly modified by the gene for connexin 37

Abstract Introduction Type 1 diabetes mellitus (T1DM) is almost inevitably accompanied by microvascular dysfunction. This could be responsible for cardiovascular events and is supposed to be caused mainly by long-term exposure to hyperglycemia. Nevertheless, relationship between duration and control of T1DM with microvascular complications can be modified by genetic factors; one of frequently discussed candidate genes is connexin37 (cx37), namely its rs1764391 (C1019&amp;gt;T (Pro319&amp;gt;Ser) polymorphism. We already observed sex specific association between cx37 polymorphism with macrovascular changes but also with retinopathy, neuropathy and diabetic foot. In the recent study, we analyzed if the impact of duration and control of T1DM on directly measured microvascular function is modified by cx37 gene polymorphism. Methods In 235 men and 227 women with T1DM (mean age 43.6 ± 13.6 years; mean duration of diabetes 22.1 ± 11.3 years) wide spectrum of clinical, laboratory and hemodynamic parameters was measured. Establishment of microvascular function measured by photoplethysmography (detection of blood volume changes in the microvasculature in lower extremities) and calculated as Oliva/Roztocil index (ORI), was analyzed. Cx37 gene polymorphism was measured by PCR-RFLP. The correlation (Pearson’s correlation coefficient) between duration of T1DM and ORI was calculated including analysis of potential modification by control of diabetes (HbA1c) and by cx37 gene polymorphism and standardized for potential confounders (sex, age, smoking, presence of hypertension, central obesity …) by multiple regression. The analysis was conducted separately for duration of T1DM below (n=256) and above (n=206) 20 years as the linear relationship between ORI and T1DM duration tends to change accordingly. Results In patients with T1DM, distribution of Cx37 genotypes did not differ from the already described populations (TT/CT/CC: 9.7/44.4/45.9%). In patients with satisfactory control of diabetes (HbA1c&amp;lt;53 mmol/mol; n=105) we detected worsening (increase) of ORI with duration of diabetes only in TT homozygotes and CT heterozygotes for duration of at least 20 years (r=0.6, p=0.006), while in patients with unsatisfactory control (HbA1c&amp;gt;60 mmol/mol;n=270), we detected worsening of ORI with duration of diabetes only in CC homozygotes, both for duration 0-20 years (r=0.35, p=0.03) and for duration of at least 20 years (r=0.47, p=0.03). Conclusion Microvascular function in satisfactory controlled T1DM was worsening with diabetes duration only in T allele carriers of Cx37 gene, the worsening was detected only for patients with duration longer than 20 years. However, if T1DM control was insufficient, microcirculation was worsening only in CC homozygotes.

Effect of progesterone on in vitro meiotic maturation of canine oocytes associated with Cx37 and Cx43 gene expression

Progesterone (P4) concentrations in canines are exceptionally high in the periovulatory period. However, the mechanisms by which P4 modulates final oocyte development in dogs remain to be characterized. The aim of this study was to evaluate the effect of P4 on meiotic development related to the gene expression of connexin 37 (Cx37) and connexin 43 (Cx43) in the canine cumlus oocyte complexes (COCs). COCs were isolated from 120 canine ovaries after a routine ovariohysterectomy. In each experiment, groups of COCs retrieved from the antral follicles were subjected to in vitro maturation (IVM) for 72 h without (control) or with P4 (50 μg/mL and 100 μg/mL) or the P4 receptor antagonist, aglepristone (RU534 at 1 μM and 10 μM). Some of the COCs recovered (from each group) after 72 h of IVM were subjected to meiotic evaluation; the remaining COCs, and those not subjected to IVM, were used to analyze the gene expression of Cx37 and Cx43 by qPCR. The results were evaluated using ANOVA. The addition of P4 increased (P < 0.05) the meiotic development compared to that in the control or aglepristone groups. The highest (P < 0.05) percentage of oocytes in the MII stage was observed upon P4 supplementation. In contrast, the highest percentage (P < 0.05) of oocytes arrested in the GV stage and the lowest (P < 0.05) percentages in the MII stage were observed for COCs cultured with aglepristone. Although a significant decrease in the mRNA levels of both connexins was observed after culturing, no effect on Cx37 and Cx43 gene expression was observed when exogenous P4 was added compared to those of the control group. However, COCs cultured with aglepristone exhibited higher (P < 0.05) expression of Cx37 and Cx43 than COCs in the control IVM-group, regardless of the concentration. In conclusion, our results suggest that a high dosage of P4 during IVM enhances the nuclear maturation of canine oocytes without altering the gene expression levels of Cx37 and Cx43. However, the increase in their expression upon treatment with a P4 antagonist indicates an in vivo role for this hormone in the endogenous modulation of both Cx37 and Cx43.

Macrovascular and microvacular changes in diabetes mellitus type 1 are modified by the gene for connexin 37 in men but not in women

Abstract Introduction Diabetes mellitus type 1 (DMT1) is a strong risk factor for macrovascular and microvascular disease. These vascular pathologies can be strongly modified by genetic factors. One of intensively investigated candidate genes is the gene for connexin37 (Cx37) (C1019&amp;gt;T (Pro319&amp;gt;Ser). The role of this gene in cardiovascular disease and diabetes mellitus had been already described in several different populations, but not in patients with DMT1. Purpose To determine whether the presence of macrovascular and microvascular changes is modified by Cx37 gene polymorphism in middle aged men and women diagnosed with DMT1 of similar age and with similar duration of DMT1. Methods In 253 men (mean age 43.0±14.5 years; mean duration of diabetes 22.6±14.0 years) and 245 women (mean age 43.9±12.9 years; mean duration of diabetes 21.3±10.5 years) macrovascular disease was measured by duplex B-Mode ultrasound and classified as Belcaro score (1–4) in carotid and femoral arteries. Microvascular disease was assessed by the presence of retinopathy, nephropathy, neuropathy and diabetic foot. Cx37 gene polymorphism was established by PCR. Results In men, in CC homozygotes we observed more advanced macrovascular changes in carotid arteries (Belcaro score more than 2) than in CT heterozygotes/TT homozygotes (7.5 vs. 15.2%; p=0.031). No significant differences were found in changes of carotid arteries in women and in changes of femoral arteries both in men and women. Regarding microvascular changes, in men, in CC homozygotes, the diabetic foot was diagnosed more frequently than in CT heterozygotes/TT homozygotes (7.4 vs. 16.1%; p=0.046). No significant differences were found in women and in other types of microvascular disease both in men and women. Conclusion These results indicate that macrovascular and microvascular changes in DMT1 can be modified by Cx37 gene polymorphism in men, but not in women. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by the Ministry of Health of the Czech Republic, grant No. NU20-01-00083 and by Ministry of Health of the Czech Republic under its conceptual development of the research organization program (Institute for Clinical and Experimental Medicine–IKEM, IN 00023001. All rights reserved.

Genetican Alysis of the Role of Connexin 37 Polymorphism in Spontaneous Abortion

Introduction: Among unique cardiovascular risk factors in women are complications during pregnancy,including miscarriage. Important risk factor is also genetic background. One of powerful candidate genesfor cardiovascular disease of atherosclerotic origin (aCVD) is gene for connexin 37 (Cx37) with stronggene-environment interaction including smoking status, that is also strong risk factor for complications inpregnancy including spontaneous abortion (SA). Material and Methods: We analysed association betweenSA and Cx37 gene polymorphism (1019C&gt;T; Pro319Ser) in 547 foetuses and its potential interaction withsmoking status of mothers. Using genetic analyses from women from general population as controls, ORsfor T allele, found in our previous studies to be protective against a CVD, were calculated. This study wasa secondary analysis of a randomized controlled trial. Results and Conclusion: T allele carriers (foetuses),had OR 0.91 (95 % CI 0.72-1.14) and no interaction with smoking was observed. In conclusion, no significantassociation between Cx37 polymorphism and SA was observed and no modifying effect of smoking statuson this association was detected.

The Role of Connexin 37 Polymorphism in Spontaneous Abortion

Among unique cardiovascular risk factors in women are complications during pregnancy, including miscarriage. Important risk factor is also genetic background. One of powerful candidate genes for cardiovascular disease of atherosclerotic origin (aCVD) is gene for connexin 37 (Cx37) with strong gene-environment interaction including smoking status, that is also strong risk factor for complications in pregnancy including spontaneous abortion (SA). We analyzed association between SA and Cx37 gene polymorphism (1019C>T; Pro319Ser) in 547 fetuses and its potential interaction with smoking status of mothers. Using genetic analyses from women from general population as controls, ORs for T allele, found in our previous studies to be protective against aCVD, were calculated. T allele carriers (fetuses), had OR 0.91 (95 % CI 0.72-1.14) and no interaction with smoking was observed. In conclusion, no significant association between Cx37 polymorphism and SA was observed and no modifying effect of smoking status on this association was detected.

Relationship between SNP rs1764391 and Susceptibility, Risk Factors, Gene-environment Interactions of Acute Myocardial Infarction in Guangxi Han Chinese Population.

Large-scale population studies showed that the SNP rs1764391 of Connexin37 gene also known as Cx37 gene may play a pivotal role in the occurrence and development of acute myocardial infarction (AMI). Published results, however, are highly controversial. This study aimed to examine the association between SNP rs1764391 of Cx37 and diseasesusceptibility, several risk factors, and gene-environment interactions of AMI in Guangxi Han Chinese population. In this study, 344 healthy controls and 344 AMI patients of Han Chinese population were enrolled. The TaqMan assay was implemented to identify genotypes of Cx37 and allele frequencies of SNP rs1764391 in both the AMI and control groups. Significant differences were detected in TT genotype frequencies of SNP rs1764391 between the AMI and control groups (P < 0.05). In the context of gender stratification, the result was also statistically different in women (P < 0.05). Each variable such as age, BMI, diabetes, high blood pressure, smoking and TC was a risk factor and correlated significantly (P < 0.05) with the development of AMI. HDL-C correlated negatively with the risk of AMI (P < 0.001). BMI, smoking or alcohol consumed interacts significantly (P < 0.017) with the presence of the SNP rs1764391 CC genotype. Evidences were presented that Cx37 rs1764391 variation may contribute to the risk for AMI, especially in women and this genetic variant may prove to be a potential biomarker for AMI risk stratification and may prove to be a useful target for therapeutic intervention to further improve prognosis in high-risk patients.

116 Differential expression of connexin 43 and 37 mRNA transcripts during the estrous cycle in canines

Gap junctions are intercellular channels that mediate cell-to-cell communication, allowing the passage of small signalling molecules. In the ovary, connexin 43 (Cx43) and connexin 37 (Cx37) are important gap junctional proteins expressed in the granulosa and cumulus cells or oocytes of several species. Gap junctions and connexins are required for the regulation of the oocytes meiotic resumption in preovulatory follicles after the surge of LH. However, unlike other species, canine oocytes do not resume meiosis before ovulation, which could be related to expression patterns of Cx43 and Cx37 during oocyte development and ovulation. Therefore, this study aimed to address the canine Cx37 and Cx43 gene expressions throughout the oestrous cycle, including the preovulatory period. The ovaries were obtained from bitches 1-6 years old (n=72) following ovariohysterectomy. The stage of the oestrous cycle was assessed according the ovarian structures and by measurements of serum progesterone (P4) levels obtained from blood samples on the day of surgery. Anestrus was &amp;lt;0.1 ng/mL P4 and absence of follicles or corpus luteum in the ovarian surface; proestrus was 0.2-2 ng/mL P4 and growing small to medium follicles on the surface of the ovaries; oestrus was 2-19 mg/mL P4 and large follicles on the surface of the ovaries; and diestrus was &amp;gt;20 ng/mL P4 and mainly predominant corpus luteum on the ovaries. For Cx43 analysis, follicular cells (granulosa and theca) were mechanically recovered from follicles (n=620) distributed into 4 types: prenatal (1 layer of granulosa cells up to the onset of antrum formation), small antral (~0.2-0.39mm), medium antral (~0.4-5.9mm), and large antral (~6-10mm). For Cx37 study, the cumulus-oocytes complexes (COC) from the same follicles were used. Total RNA extraction was performed, and the evaluation of gene expression levels was achieved by relative quantification quantitative PCR analysis in follicular cells and COC. The data from at least 3 independent experiments for each gene were evaluated by ANOVA. The gene expression of both Connexins were observed in all stages of follicular development; however, the mRNA levels varied over the oestrous cycle. Both Cx43 and Cx37 transcripts showed the highest (P&amp;lt;0.05) levels at anestrus when compared to other phases. The mRNA levels of both genes remained without changes in large follicles at oestrus stage, suggesting that, in contrast to other mammals where LH down-regulates connexins expression leading to the subsequent loss of intercellular coupling, the communication between the oocyte and follicular cells was maintained in canines. In conclusion, these 2 connexin genes were differentially expressed in canine follicular cells and COC during the follicular development. The maintenance of the gene expression of these connexins at the final follicular growth may be involved in the prolonged meiotic arrest in this species. Supported by Ga grant from FONDECYT (1171670).

The expression of connexin 37 gene in the aorta of rat models of dyslipidemia, hypertension and dicarbonyl stress

Aim: Connexin 37 (Cx37) participates in the communication of vascular wall cells with monocytes and macrophages. Polymorphism of the Cx37 gene is considered as a possible risk factor for atherosclerosis. However, ambiguous results are observed in humans. We tested the expression of Cx37 in the aorta of rat models of dyslipidemia and hypertension to get information about the possible role of Cx37 in the pathogenesis of model illnesses.

Improving myocardial fractional flow reserve in coronary atherosclerosis via CX37 gene silence: a preclinical validation study in pigs.

The purpose of this study was to evaluate the effect of CX37 gene silence on myocardial fractional flow reserve (FFR). A total of 90 male pigs were randomly divided into saline, mock and 3 different doses (5, 10 and 20 µl) of CX37 viral suspension groups that could induce coronary plaque formation with high-fat diet. After performing myocardial FFR by intravascular ultrasound, different doses of CX37 viral suspension, saline and mock small interfering RNA (siRNA) were transfected into the related coronary. The FFR, the myocardial enzymes and the cardiac structures and functions of the pigs were detected at baseline, 4th, 8th and 12th week after transfection, respectively. Repeated measures analysis of variance comparison showed that the difference in the FFR among the 5 groups was statistically significant (F = 27.0, P < 0.01). Post hoc analysis showed that FFR were highest in the siRNA CX37 group (20 µl), followed by the siRNA CX37 group (10 µl) and the siRNA CX37 group (5 µl), and lowest in the mock and saline groups. Left ventricular end-diastolic diameter was significantly smaller and ejection fraction was obviously higher in the 3 siRNA CX37 groups compared with the untreated groups. Our study showed that FFR levels increased along with decreased doses of siRNA CX37 lentivirus, indicating that siRNA CX37 lentivirus may reduce the risk of coronary atherosclerosis and provide a potential approach to treat coronary heart disease.

Connexin37 deficiency alters organic bone matrix, cortical bone geometry, and increases Wnt/β-catenin signaling

Deletion of connexin (Cx) 37 in mice leads to increased cancellous bone mass due to defective osteoclast differentiation. Paradoxically; however, Cx37-deficient mice exhibit reduced cortical thickness accompanied by higher bone strength, suggesting a contribution of Cx37 to bone matrix composition. Thus, we investigated whether global deletion of Cx37 alters the composition of organic bone extracellular matrix. Five-month-old Cx37−/− mice exhibited increased marrow cavity area, and periosteal and endocortical bone surface resulting in higher total area in tibia compared to Cx37+/+ control mice. Deletion of Cx37 increased genes involved in collagen maturation (loxl3 and loxl4) and glycosaminoglycans- (chsy1, chpf and has3) proteoglycans- associated genes (biglycan and decorin). In addition, expression of type II collagen assessed by immunostaining was increased by 82% whereas collagen maturity by picrosirius-polarizarion tended to be reduced (p=0.071). Expression of glycosaminoglycans by histochemistry was decreased, whereas immunostaining revealed that biglycan was unchanged and decorin was slightly increased in Cx37−/− bone sections. Consistent with these in vivo findings, MLO-Y4 osteocytic cells silenced for Cx37 gene exhibited increased mRNA levels for collagen synthesis (col1a1 and col3a1) and collagen maturation (lox, loxl1 and loxl2 genes). Furthermore, mechanistic studies showed Wnt/β-catenin activation in MLO-Y4 osteocytic cells, L5 vertebra, and authentic calvaria-derived osteocytes isolated by fluorescent-activated cell sorter. Our findings demonstrate that altered profile of the bone matrix components in Cx37-deficient mice acts in favor of higher resistance to fracture in long bones.

Connexin 37 and 43 gene and protein expression and developmental competence of isolated ovine secondary follicles cultured in vitro after vitrification of ovarian tissue

Cryoinjuries caused by vitrification of tissues and organs lead to the loss of membrane proteins that mediate intercellular communications, such as connexins 37 (Cx37) and 43 (Cx43). Thus, the present study aimed to evaluate ovine Cx37 and Cx43 gene and protein expressions and developmental competence by in vitro–cultured secondary follicles retrieved from vitrified ovarian tissue. Ovarian fragments for the same ovary pair were distributed into six treatments: (1) fresh ovarian tissue (FOT); (2) vitrified ovarian tissue (VOT); (3) isolated follicles from fresh ovarian tissue (FIF); (4) isolated follicles from vitrified ovarian tissue; (5) isolated follicles from fresh ovarian tissue followed by in vitro culture (CFIF); (6) isolated follicles from vitrified ovarian tissue followed by in vitro culture (CVIF). In all treatments, Cx37 and Cx43 gene and protein expression patterns were evaluated by reverse transcription polymerase chain reaction and immunocytochemistry. In addition, secondary follicles were analyzed according to follicular integrity and growth, apoptosis, and cell proliferation. In vitro–cultured secondary follicles (CFIF and CVIF) were evaluated based on morphology (extruded follicles), antrum formation, and viability. The percentage of intact follicles was higher, whereas antrum formation, oocyte extrusion rate, and follicle viability were lower in CVIF than in CFIF treatment (P < 0.05). Terminal deoxynucleotidyl transferase–mediated biotinylated deoxyuridine triphosphates nick end-labeling assay demonstrated that apoptosis was absent in FIF, whereas follicles from all other treatments showed positive labeling. Cell proliferation index was higher in isolated follicles from vitrified ovarian tissue and CVIF treatments than in follicles from FIF. Expression of Cx43 messenger RNA was lower in CVIF treatment when compared with follicles from all other treatments (P < 0.05). Follicle Cx37 messenger RNA levels did not show alterations in any treatment (P > 0.05). Cx37 and Cx43 immunolabeling was localized mainly on granulosa cells and oocytes, respectively. In conclusion, isolation of ovine secondary follicles could be done successfully after vitrification of ovarian tissue, and the basement membrane integrity remained intact after in vitro culture. Although the gene and protein expression of Cx37 did not change after vitrification of ovarian tissue, Cx43 turned out to be altered in secondary follicles after vitrification and in vitro culture.

Smoking impairs and circulating stem cells favour the protective effect of the T allele of the connexin37 gene in ischemic heart disease – A multinational study

BackgroundThe connexin 37 (Cx37) gene is considered to be a candidate gene for ischemic heart disease (IHD). We analyzed the association between the C1019 > T (Pro319 > Ser) variant of the Cx37 gene and IHD in patients in the Czech Republic, Croatia, Hungary and Romania with regard to the presence/absence of selected cardiovascular risk factors (RF). In a complementary study, we analyzed the association between the Cx37 gene and circulating stem and endothelial progenitor cells in healthy women. MethodsThe study population comprised 2396 patients (663 women) with IHD. The control population comprised 2476 subjects (1, 337 women). Additionally, in 662 healthy women, the association between the Cx37 gene and circulating stem and endothelial progenitor cells was analyzed. ResultsThe strongest protective effect of the Cx37 T allele was detected in non-smoking patients without diabetes mellitus and hypertension (OR 0.610, 95% CI 0.377–0.990); a similar effect was found in non-smoking men (OR 0.781, 95% CI 0.628–0.971); weaker effect was found in non-smoking women (OR 0.768, 95% CI 0.560–1.050). In non-smoking healthy women, stem cells were significantly higher in TT than in CT and CC carriers (p for trend 0.011). Additionally, non-smoking TT carriers had significantly higher number of stem cells than past and current smoking TT carriers (p for trend = 0.006); no such trend was found in CT and CC carriers. ConclusionsThe protective effect of the T allele of the Cx37 gene might be strongly modified by smoking; in women, this effect could be mediated through stem cells.

GW26-e4697 Improved myocardial fractional flow reserve in pigs with by Cx37 gene silence

GW26-e4697 Improved myocardial fractional flow reserve in pigs with by Cx37 gene silence

Shear stress-induced atherosclerotic plaque composition in ApoE−/− mice is modulated by connexin37

ObjectiveShear stress patterns influence atherogenesis and plaque stability; low laminar shear stress (LLSS) promotes unstable plaques whereas oscillatory shear stress (OSS) induces more stable plaques. Endothelial connexin37 (Cx37) expression is also regulated by shear stress, which may contribute to localization of atherosclerotic disease. Moreover, Cx37 reduces initiation of atherosclerosis by inhibiting monocyte adhesion. The present work investigates the effect of Cx37 on the phenotype of plaques induced by LLSS or OSS. MethodsShear stress-modifying casts were placed around the common carotid artery of ApoE−/− or ApoE−/−Cx37−/− mice, and animals were placed on a high-cholesterol diet for 6 or 9 weeks. Atherosclerotic plaque size and composition were assessed by immunohistochemistry. ResultsPlaque size in response to OSS was increased in ApoE−/−Cx37−/− mice compared to ApoE−/− animals. Most plaques contained high lipid and macrophage content and a low amount of collagen. In ApoE−/− mice, macrophages were more prominent in LLSS than OSS plaques. This difference was reversed in ApoE−/−Cx37−/− animals, with a predominance of macrophages in OSS plaques. The increase in macrophage content in ApoE−/−Cx37−/− OSS plaques was mainly due to increased accumulation of M1 and Mox macrophage subtypes. Cx37 expression in macrophages did not affect their proliferation or their polarization in vitro. ConclusionCx37 deletion increased the size of atherosclerotic lesions in OSS regions and abrogated the development of a stable plaque phenotype under OSS in ApoE−/− mice. Hence, local hemodynamic factors may modify the risk for adverse atherosclerotic disease outcomes associated to a polymorphism in the human Cx37 gene.

Exogenous Exposure to Estradiol Benzoate or Flutamide at the Weaning Age Alters Expression of Connexin Isoforms in the Initial Segment of Male Rat

ABSTRACTConnexin (Cx) is a complex which allows direct communication between neighboring cells via exchange of signaling molecules and eventually leads to functional harmony of cells in a tissue. The initial segment (IS) is an excurrent duct of male reproductive tract and expression of numerous genes in the IS are controlled by androgens and estrogens. The effects of these steroid hormones on gene expression in the IS during postnatal development have not extensively examined. The present research investigated expressional modulation of Cx isoforms in the IS by exogenous exposure to estrogen agonist, estradiol benzoate (EB), or androgen antagonist, flutamide (Flu), at weaning age. Two different doses of EB or Flu were subcutaneously administrated in 21-day old of male rats, and expressional changes of Cx isoforms in the adult IS were analyzed by quantitative real-time PCR. Treatment of a low-dose EB (0.015 μg/kg body weight) resulted in an increased expression of Cx31 gene and a decreased expression of Cx37 gene. A high-dose EB (1.5 μg/kg body weight) treatment caused an increase of Cx31 gene expression. Increased levels of Cx30.3 and Cx40 transcripts were observed with a low-dose Flu (500 μg/kg body weight) treatment. Treatment of high-dose Flu (50 mg/kg body weight) led to expressional increases of Cx30.3, 40, and 43 genes. Our previous and present findings suggest differential responsiveness on gene expression of Cx isoforms in the IS by androgens and estrogens at different postnatal ages.

Exogenous exposure to estradiol benzoate or flutamide at the weaning age alters expression of connexin isoforms in the initial segment of male rat.

Connexin (Cx) is a complex which allows direct communication between neighboring cells via exchange of signaling molecules and eventually leads to functional harmony of cells in a tissue. The initial segment (IS) is an excurrent duct of male reproductive tract and expression of numerous genes in the IS are controlled by andevrepogens and estrogens. The effects of these steroid hormones on gene expression in the IS during postnatal development have not extensively examined. The present research investigated expressional modulation of Cx isoforms in the IS by exogenous exposure to estrogen agonist, estradiol benzoate (EB), or andevrepogen antagonist, flutamide (Flu), at weaning age. Two different doses of EB or Flu were subcutaneously administrated in 21-day old of male rats, and expressional changes of Cx isoforms in the adult IS were analyzed by quantitative real-time PCR. Treatment of a low-dose EB (0.015 μg/kg body weight) resulted in an increased expression of Cx31 gene and a decreased expression of Cx37 gene. A high-dose EB (1.5 μg/kg body weight) treatment caused an increase of Cx31 gene expression. Increased levels of Cx30.3 and Cx40 transcripts were observed with a low-dose Flu (500 μg/kg body weight) treatment. Treatment of high-dose Flu (50 mg/kg body weight) led to expressional increases of Cx30.3, 40, and 43 genes. Our previous and present findings suggest differential responsiveness on gene expression of Cx isoforms in the IS by andevrepogens and estrogens at different postnatal ages.

GAP JUNCTIONS AND CONNEXIN HEMICHANNELS UNDERPIN HAEMOSTASIS AND THROMBOSIS

Connexins are a widespread family of membrane proteins that assemble into hexameric hemichannels, also known as connexons. Connexons regulate membrane permeability in individual cells or couple between adjacent cells to...

Mutations in cardiovascular connexin genes.

Connexins (Cxs) form a family of transmembrane proteins comprising 21 members in humans. Cxs differ in their expression patterns, biophysical properties and ability to combine into homomeric or heteromeric gap junction channels between neighbouring cells. The permeation of ions and small metabolites through gap junction channels or hemichannels confers a crucial role to these proteins in intercellular communication and in maintaining tissue homeostasis. Among others, Cx37, Cx40, Cx43, Cx45 and Cx47 are found in heart, blood and lymphatic vessels. Mutations or polymorphisms in the genes coding for these Cxs have not only been implicated in cardiovascular pathologies but also in a variety of other disorders. While mutations in Cx43 are mostly linked to oculodentodigital dysplasia, Cx47 mutations are associated with Pelizaeus-Merzbacher-like disease and lymphoedema. Cx40 mutations are principally linked to atrial fibrillation. Mutations in Cx37 have not yet been described, but polymorphisms in the Cx37 gene have been implicated in the development of arterial disease. This review addresses current knowledge on gene mutations in cardiovascular Cxs systematically and links them to alterations in channel properties and disease.

Association Between 1019C/T Polymorphism in the Connexin 37 Gene and Essential Hypertension

To investigate the association between the CX 37 1019C/T polymorphism and the susceptibility to essential hypertension (EH). A total of 1126 cases of EH were diagnosed in the People's Hospital of Wuxi City, China. A control group consisted of 874 healthy people, i.e., non-EH patients. All cases were genotyped by DNA sequencing. Polymorphism C1019T on the Connexin37 gene was found in the whole population. The distribution of three genotype frequencies in both groups was in accordance with the Hardy-Weinberg equilibrium. The frequency of the CX37C allele was higher in EH patients (57.4% vs. 42.1%, χ(2)=92.5, P<0.01) compared to the control group. The frequency of C carriers (CC+TC) was 80.5% in EH patients compared to 66.7% in the control (χ(2)=49.0, P<0.01). EH risk was significantly increased in carriers of C the allele (CC+TC) over that in the TT homozygote (OR=2.06, 95% CI: 1.68 ∼ 2.52). Subsequent stratified analyses demonstrate that a significant difference exists in the frequency of C carriers between male EH patients and controls (79.2% vs. 69.1%, χ(2)=13.4, P<0.01) and in female EH patients and the control group (81.8% vs. 64.4%, χ(2)=38.7, P<0.01). The carriers of the C allele had higher EH risk compared with the TT homozygote without sex differences (male: OR=1.71, 95% CI: 1.28 ∼ 2.27; female: OR=2.48, 95%CI: 1.85 ∼ 3.31). The C allele in the CX37 gene might be associated with the susceptibility to EH in population of Wuxi, China.