Connexin 43-modified bone marrow stromal cells reverse the imatinib resistance of K562 cells via Ca 2+ -dependent gap junction intercellular communication / 中华医学杂志(英文版)

BACKGROUND@#Imatinib mesylate (IM) resistance is an emerging problem for chronic myeloid leukemia (CML). Previous studies found that connexin 43 (Cx43) deficiency in the hematopoietic microenvironment (HM) protects minimal residual disease (MRD), but the mechanism remains unknown.@*METHODS@#Immunohistochemistry assays were employed to compare the expression of Cx43 and hypoxia-inducible factor 1α (HIF-1α) in bone marrow (BM) biopsies of CML patients and healthy donors. A coculture system of K562 cells and several Cx43-modified bone marrow stromal cells (BMSCs) was established under IM treatment. Proliferation, cell cycle, apoptosis, and other indicators of K562 cells in different groups were detected to investigate the function and possible mechanism of Cx43. We assessed the Ca 2+ -related pathway by Western blotting. Tumor-bearing models were also established to validate the causal role of Cx43 in reversing IM resistance.@*RESULTS@#Low levels of Cx43 in BMs were observed in CML patients, and Cx43 expression was negatively correlated with HIF-1α. We also observed that K562 cells cocultured with BMSCs transfected with adenovirus-short hairpin RNA of Cx43 (BMSCs-shCx43) had a lower apoptosis rate and that their cell cycle was blocked in G0/G1 phase, while the result was the opposite in the Cx43-overexpression setting. Cx43 mediates gap junction intercellular communication (GJIC) through direct contact, and Ca 2+ is the key factor mediating the downstream apoptotic pathway. In animal experiments, mice bearing K562, and BMSCs-Cx43 had the smallest tumor volume and spleen, which was consistent with the in vitro experiments.@*CONCLUSIONS@#Cx43 deficiency exists in CML patients, promoting the generation of MRD and inducing drug resistance. Enhancing Cx43 expression and GJIC function in the HM may be a novel strategy to reverse drug resistance and promote IM efficacy.

Effect of gap junction blockers on hippocampal ripple energy expression in rats with status epilepticus / 中国当代儿科杂志

OBJECTIVES@#To study the effect of gap junction blockers, quinine (QUIN) and carbenoxolone (CBX), on hippocampal ripple energy expression in rats with status epilepticus (SE).@*METHODS@#A total of 24 rats were randomly divided into four groups: model, QUIN, valproic acid (VPA), and CBX (@*RESULTS@#Ripple expression was observed in the hippocampal CA1, CA3, and dentate gyrus regions of normal rats. After 10 minutes of PILO injection, all groups had a gradual increase in mean ripple energy expression compared with 1 day before modeling, with the highest expression level before chloral hydrate injection in the model, VPA and CBX groups (@*CONCLUSIONS@#The change in ripple energy can be used as a quantitative indicator for early warning of seizures, while it cannot predict seizures in the interictal period. Gap junction blockers can reduce ripple energy during seizures.

Gap junction-mediated cell-to-cell communication in oral development and oral diseases: a concise review of research progress / 国际口腔科学杂志·英文版

Homoeostasis depends on the close connection and intimate molecular exchange between extracellular, intracellular and intercellular networks. Intercellular communication is largely mediated by gap junctions (GJs), a type of specialized membrane contact composed of variable number of channels that enable direct communication between cells by allowing small molecules to pass directly into the cytoplasm of neighbouring cells. Although considerable evidence indicates that gap junctions contribute to the functions of many organs, such as the bone, intestine, kidney, heart, brain and nerve, less is known about their role in oral development and disease. In this review, the current progress in understanding the background of connexins and the functions of gap junctions in oral development and diseases is discussed. The homoeostasis of tooth and periodontal tissues, normal tooth and maxillofacial development, saliva secretion and the integrity of the oral mucosa depend on the proper function of gap junctions. Knowledge of this pattern of cell-cell communication is required for a better understanding of oral diseases. With the ever-increasing understanding of connexins in oral diseases, therapeutic strategies could be developed to target these membrane channels in various oral diseases and maxillofacial dysplasia.

Formation of gap junctions between adipose stem cells-derived Schwann cells in a rat model of dyskinesia induced by brain injury / 南方医科大学学报

OBJECTIVE@#To investigate the formation of gap junctions between Schwann cells derived from differentiated adipose stem cells implanted in a rat model of dyskinesia induced by brain injury and its positive effect in promoting functional recovery of the rats.@*METHODS@#In a rat model of hemiplegia induced by motor cortex injury, adipose stem cells or Schwann cells differentiated from adipose stem cells, either with or without RNAi-mediated silencing of Cx43, were transplanted orthotopically in the lesion. The recovery of the motor function of the rats was observed and scored after the transplantation. Rat brain tissues were sampled to detect the expressions of nerve growth factor (NGF) using Western blotting and RT-PCR.@*RESULTS@#All the 3 cell transplantation therapies obviously improved the motor function scores of the rats as compared with the control rats. The expression of NGF in the brain tissue was significantly lower in the control group than in the cell transplantation groups. NGF expression in the brain tissues of rats receiving transplantation of Schwann cells with Cx43 gene silencing was lower than that in rats receiving Schwann cells without Cx43 silencing, and was similar with that in rats transplanted with adipose stem cells. The results of RT-PCR showed that NGF mRNA level in the control group was significantly lower than that in the other 3 groups. NGF mRNA expression was the highest in Schwann cell group without Cx43 silencing, followed by adipose stem cell group, and then by Schwann cell group with Cx43 silencing.@*CONCLUSIONS@#In the rat model of dyskinesia induced by brain injury, transplantations of adipose stem cells and adipose stem cells-derived Schwann cells both promote the functional recovery of brain damage, in which gap junction protein Cx43 plays an important role to promote functional gap junction formation possibly by enhancing NGF expression.

The biological functions of cell-to-cell connection over long distance--membrane nanotube / 生理学报

Cell-to-cell connections provide conduits for signal exchanges, and play important functional roles in physiological and pathological processes of multicellular organisms. Membrane nanotubes are common long-distance connections between cells, not only transfer molecule signals and mitochondria, but also cooperate with gap junction and other cell-to-cell communications to transfer signals. During the last decade, there are many studies about membrane nanotubes, which focus on the similarities and differences between membrane nanotubes and other cell-to-cell communications, as well as their biological functions. In the present review, we summarized the latest findings about the structural diversity, the similarities and differences in signal transmission with other types of cell-to-cell communications, and physiological and pathological roles of membrane nanotubes.

Angiotensin II and TGF-β1 Induce Alterations in Human Amniotic Fluid-Derived Mesenchymal Stem Cells Leading to Cardiomyogenic Differentiation Initiation

BACKGROUND AND OBJECTIVES: Human amniotic fluid-derived mesenchymal stem cells (AF-MSCs) may be a valuable source for cardiovascular tissue engineering and cell therapy. The aim of this study is to verify angiotensin II and transforming growth factor-beta 1 (TGF-β1) as potential cardiomyogenic differentiation inducers of AF-MSCs. METHODS AND RESULTS: AF-MSCs were obtained from amniocentesis samples from second-trimester pregnant women, isolated and characterized by the expression of cell surface markers (CD44, CD90, CD105 positive; CD34 negative) and pluripotency genes (OCT4, SOX2, NANOG, REX1). Cardiomyogenic differentiation was induced using different concentrations of angiotensin II and TGF-β1. Successful initiation of differentiation was confirmed by alterations in cell morphology, upregulation of cardiac genes-markers NKX2-5, TBX5, GATA4, MYH6, TNNT2, DES and main cardiac ion channels genes (sodium, calcium, potassium) as determined by RT-qPCR. Western blot and immunofluorescence analysis revealed the increased expression of Connexin43, the main component of gap junctions, and Nkx2.5, the early cardiac transcription factor. Induced AF-MSCs switched their phenotype towards more energetic and started utilizing oxidative phosphorylation more than glycolysis for energy production as assessed using Agilent Seahorse XF analyzer. The immune analysis of chromatin-modifying enzymes DNMT1, HDAC1/2 and Polycomb repressive complex 1 and 2 (PRC1/2) proteins BMI1, EZH2 and SUZ12 as well as of modified histones H3 and H4 indicated global chromatin remodeling during the induced differentiation. CONCLUSIONS: Angiotensin II and TGF-β1 are efficient cardiomyogenic inducers of human AF-MSCs; they initiate alterations at the gene and protein expression, metabolic and epigenetic levels in stem cells leading towards cardiomyocyte-like phenotype formation.

The role of under-investigated connexins in musculoskeletal tissue: a brief review with emphasis on bone tissue / El papel de las escasamente investigadas conexinas en el tejido músculo-esquelético: una breve revisión con énfasis en el tejido óseo

Connexins (Cxs) are a family of transmembrane proteins that form gap junctions and hemi-channels, which mediate cell-cell communication between neighboring cells and the respective extracellular milieu in different tissues. Most tissues and cell types throughout the body express one or more Cx proteins, highlighting its importance in regulating cell growth, differentiation, adhesion, migration, cell death and others. Moreover, Cx can propagate intracellular signals through its C-terminus domain, and thus function beyond a mere channel. Cx43 is the most highly expressed and most well studied Cx in bone and musculoskeletal tissues, although Cx40, Cx45, Cx46 and more recently, the Cx37 have been described in bone tissue, along with Cx26, Cx32 and Cx39 in other musculoskeletal tissues. Here, we discuss the basic structure of gap junctions and the role of the Cxs in musculoskeletal tissue, with special focus on Cx37. (AU)

Las conexinas (Cxs) son una familia de proteínas transmembrana que forman uniones en hendidura y hemicanales encargados de mediar la comunicación entre células vecinas y el respectivo medio extracelular en diferentes tejidos. La mayoría de los tejidos y células expresan una o más proteínas conexina, jugando un papel importante en la regulación de la proliferación celular, diferenciación, adhesión, migración y muerte celular, entre otras funciones. Además de actuar como un canal, las conexinas pueden propagar señales intracelulares a través del dominio C-terminal. La Cx43 es la conexina mas expresada y mejor estudiada en el tejido óseo y el músculo, aunque las Cx40, Cx45, Cx46, y mas recientemente Cx37, son también detectadas en el hueso. A su vez la expresión de la Cx26, Cx32 y Cx39 ha sido observada en otros tejidos músculoesqueléticos. En este manuscrito describimos la estructura básica de las uniones tipo gap y el papel que las Cxs, y en especial la Cx37, tienen en tejidos músculo-esqueléticos. (AU)

Correlation of connexin 43 with testicular tumors / 中华男科学杂志

Gap junctions (GJ), as a special membrane structure between adjacent cells, are composed of connexins (Cx) and regulate the proliferation and differentiation of cells. Studies show that gap junctional intercellular communication is weakened or lost in most tumor cells and this abnormality is often accompanied by changed expression of Cxs. Cx43 is a major connexin in the testis tissue. This review focuses on the latest progress in the studies of Cx43 in testicular tumors.

Oculodentodigital Dysplasia Presenting as Spastic Paraparesis: The First Genetically Confirmed Korean Case and a Literature Review

Oculodentodigital dysplasia (ODDD) is a rare autosomal dominant inherited disease caused by mutations of the human gap junction alpha 1 gene, which encodes the protein Connexin-43. Patients with ODDD may present with neurological deficits with a typical pleiotropic combination of characteristic craniofacial, ophthalmological, phalangeal, and dental anomalies. In this report, we describe the first genetically confirmed Korean ODDD patient, who presented with spastic paraparesis. We will also review the neurological aspects of ODDD as reported in the literature.

Long Term Speech Perception Outcomes of Cochlear Implantation in Gap Junction Protein Beta 2 Related Hearing Loss

BACKGROUND AND OBJECTIVES: The mutation of the gap junction protein beta 2 (GJB2) gene is the predominant cause of autosomal recessive non-syndromic hearing loss. The purpose of this study was to evaluate the speech perception outcome after cochlear implantation according to the presence of a GJB2 mutation. SUBJECTS AND METHODS: During the period from March 2004 to February 2005, 38 patients underwent cochlear implantation at Asan Medical Center. Genetic factors and speech perception were evaluated in all subjects, and the patients were grouped according to the presence of a GJB2 mutation. The two groups were carefully matched according to the age at cochlear implantation. We analyzed four mutations in the GJB2 gene: 35delG, 167delT, 235delC, and E114G. Speech perception outcomes were measured using the open set, 1 and 2 syllables, the comprehension test, the Meaningful Auditory Integration Scale, the categories of auditory performance, and the Speech Intelligibility Rating scores. The evaluations were performed before the operation, 6 and 12 months thereafter, and then annually up to nine years after cochlear implantation. RESULTS: Fifteen patients had bi-allelic GJB2 mutations (11 with E114G and 4 with 235delC), whereas the remaining 23 had wild type alleles. For the age-matched analysis, 14 patients were selected and divided into two groups of 7 subjects each: GJB2 mutation and no mutation (i.e., deafness of unknown origin). Overall, all patients showed improvement of speech perception outcome after cochlear implantation. There was no difference in the improvement between patients with and without GJB2 mutations at the 5-year and 9-year follow up. The pattern of improvement throughout the duration of the follow-up also showed no difference between the two groups. CONCLUSIONS: Similar outcomes of speech perception are expected after cochlear implantation in pediatric patients with or without GJB2 mutation.

Effect of magnesium ion on human osteoblast activity

Magnesium, a promising biodegradable metal, has been reported in several studies to increase bone formation. Although there is some information regarding the concentrations of magnesium ions that affect bone remodeling at a cellular level, little is known about the effect of magnesium ions on cell gap junctions. Therefore, this study aimed to systematically investigate the effects of different concentrations of magnesium on bone cells, and further evaluate its effect on gap junctions of osteoblasts. Cultures of normal human osteoblasts were treated with magnesium ions at concentrations of 1, 2 and 3 mM, for 24, 48 and 72 h. The effects of magnesium ions on viability and function of normal human osteoblasts and on gap junction intercellular communication (GJIC) in osteoblasts were investigated. Magnesium ions induced significant (P<0.05) increases in cell viability, alkaline phosphate activity and osteocalcin levels of human osteoblasts. These stimulatory actions were positively associated with the concentration of magnesium and the time of exposure. Furthermore, the GJIC of osteoblasts was significantly promoted by magnesium ions. In conclusion, this study demonstrated that magnesium ions induced the activity of osteoblasts by enhancing GJIC between cells, and influenced bone formation. These findings may contribute to a better understanding of the influence of magnesium on bone remodeling and to the advance of its application in clinical practice.

Importância das comunicações intercelulares para o desenvolvimento de folículos ovarianos / Intercellular communications in ovarian follicles

Durante a foliculogênese em mamíferos, ocorre um longo e complexo processo no qual o oócito adquire a competência necessária para a fecundação. Nesse processo ocorre uma comunicação metabólica bidirecional entre os oócitos e as células somáticas dentro do folículo que garante substratos para o oócito em desenvolvimento. Essa comunicação é mediada pelas junções celulares (junções comunicantes e junções aderentes) presentes nas projeções transzonais. As junções celulares e moléculas de adesão são responsáveis principalmente por promover a adesão entre as células foliculares; mas podem atuar em vias de sinalização celular e na regulação da transcrição gênica nas células somáticas e oócitos. Além disso, as junções comunicantes (junções gap) são canais intermembranares que intermediam a comunicação entre essas células através da passagem de pequenas moléculas. Essas junções comunicantes são compostas por proteínas denominadas conexinas; as conexinas 37 e 43 são as predominantes nos folículos ovarianos. Dessa forma, o conhecimento acerca das junções celulares é de extrema importância para o estudo da foliculogênese. A presente revisão teve como objetivo abordar os principais tipos de junções celulares existentes entre as células foliculares, com destaque para as junções gap e as principais proteínas de membranas (conexinas) presentes nos diferentes estágios do desenvolvimento folicular.

During the mammalian folliculogenesis, a long and complex process occurs, which the oocyte acquires the necessary competence for fecundation. In this process there is a metabolic bidirectional communication among the oocyte and somatic cells inside the follicle, which provides substrates for the oocyte developmental competence. This communication is mediated by cellular junctions (occlusions, adherens and gap junctions) localized in the transzonal projections. Cellular junctions and adhesion mollecules are responsable mainly for promoving the adhesion among follicular cells, however they can act in cellular signaling pathways and in regulation of genic transcription in the follicular cells and oocyte. Moreover, the communication junctions (gap junctions) are intermembrane channels that intermediate the communication among these cells through the passage of small molecules. These gap junctions are composed by connexins, of which the connexins 37 and 43 are the most frequently found in the ovarian follicle. Thus, knowledge of these cellular junctions are of great importance for studying the folliculogenesis process. The aim of this review was to report the main types of cellular junctions localized among the follicular cells, especially the gap junctions and the main membrane proteins (connexins) found in different stages of the follicular development.

Quinoline derivative PQ1 combined with cisplatin promotes the proliferation and gap junction communication of prostate cancer PC3 cells / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the effects of the quinoline derivative PQ1 combined with cisplatin on the proliferation and gap junction communication of prostate cancer PC3 cells.</p><p><b>METHODS</b>We cultured in vitro prostate cancer PC3 cells and divided them into DMSO blank control, cisplatin control, and cisplatin (10 mg/ml) plus PQ1 (1, 2, 5, 10, and 15 μmol/L) groups. We measured the proliferation of the prostate cancer PC3 cells, determined the expressions of the connexin 43 (Cx43) mRNA and protein by RT-PCR and Western blot, and compared the indexes among different groups.</p><p><b>RESULTS</b>Cisplatin combined with PQl at 1 - 10 μmol/L significantly inhibited the proliferation of the PC3 cells and the inhibition rate rose in a concentration- and time-dependent manner, from (48.72 ± 0.98)% vs (50.33 ± 0.62)% at 0 μmol/L to (77.38 ± 1.12)% vs (83.50 ± 1.05)% at 15 μmol/L at 24 and 48 hours (P < 0.05). Compared with the cisplatin control, cisplatin combined with PQ1 at 1, 2, 5, 10, and 15 μmol/L increased the expression of Cx43 mRNA from 0.379 ± 0.113 to 0.669 ± 0.031, 0.831 ± 0. 127, 0.769 ± 0.100, 0.532 ± 0.086, and 0.475 ± 0.134, respectively (P < 0.05), and cisplatin combined with PQ1 at 1, 2, 5, and 10 μmol/L elevated that of Cx43 protein from 0.138 ± 0.146 to 0.263 ± 0.111, 0.306 ± 0.152, 0.415 ± 0.280, and 0.643 ± 0.310, respectively (P < 0.05).</p><p><b>CONCLUSION</b>The quinoline derivative PQ1 can promote the gap junction communication of prostate cancer PC3 cells and enhance the killing effect of cisplatin on PC3 cells by upregulating the expressions of Cx43 mRNA and protein.</p>

Gap junction blockage promotes cadmium-induced apoptosis in BRL 3A derived from Buffalo rat liver cells

Gap junctions mediate direct communication between cells; however, toxicological cascade triggered by nonessential metals can abrogate cellular signaling mediated by gap junctions. Although cadmium (Cd) is known to induce apoptosis in organs and tissues, the mechanisms that underlie gap junction activity in Cd-induced apoptosis in BRL 3A rat liver cells has yet to be established. In this study, we showed that Cd treatment decreased the cell index (a measure of cellular electrical impedance) in BRL 3A cells. Mechanistically, we found that Cd exposure decreased expression of connexin 43 (Cx43), increased expression of p-Cx43 and elevated intracellular free Ca2+ concentration, corresponding to a decrease in gap junctional intercellular communication. Gap junction blockage pretreatment with 18β-glycyrrhizic acid (GA) promoted Cd-induced apoptosis, involving changes in expression of Bax, Bcl-2, caspase-3 and the mitochondrial transmembrane electrical potential (Δψm). Additionally, GA was found to enhance ERK and p38 activation during Cd-induced activation of mitogen-activated protein kinases, but had no significant effect on JNK activation. Our results indicated the apoptosis-related proteins and the ERK and p38 signaling pathways may participate in gap junction blockage promoting Cd-induced apoptosis in BRL 3A cells.

Expression of Connexin 43 in the Myocardium in Sudden Unexplained Nocturnal Death Syndrome / 대한법의학회지

Sudden unexplained nocturnal death syndrome (SUNDS) occurs predominantly in Southeast Asian people including Koreans. SUNDS is problematic for forensic pathologists because the diagnosis depends on the "exclusion of diagnosis." Moreover, the pathogenesis of SUNDS is still unclear although some cases are known to be intimately related to the Brugada syndrome. Connexin 43 (Cx43) is a principal protein of gap junction in adult cardiac myocytes, being distributed to the intercalated discs and phosphorylated in normal condition. Ischemia and hypoxia alter the expression of total Cx43 (tCx43) resulting in redistribution of non-phosphorylated Cx43 (npCx43) to the sarcoplasm or lateral cell borders of cardiac myocytes by continuing dephosphorylation. This study aimed to compare the immunoexpression pattern of Cx43 in the cardiac myocytes of SUNDS and ischemic heart disease (IHD). The study group was 26 cases of SUNDS and the control group of 24 cases of IHD with severe coronary atherosclerosis, showing no myocardial ischemic change. There was a significantly different expression of both tCx43 and npCX43 between the SUNDS and IHD group. A greater reduction in both tCx43 and npCx43 and a more delayed redistribution pattern was seen in the myocardium of SUNDS when compared with IHD. In conclusion, these results suggest that the reduced Cx43 expression in SUNDS may be inherent and indicate a risk of arrhythmia.

Neuropeptide Y, substance P, and human bone morphogenetic protein 2 stimulate human osteoblast osteogenic activity by enhancing gap junction intercellular communication

Bone homeostasis seems to be controlled by delicate and subtle “cross talk” between the nervous system and “osteo-neuromediators” that control bone remodeling. The purpose of this study was to evaluate the effect of interactions between neuropeptides and human bone morphogenetic protein 2 (hBMP2) on human osteoblasts. We also investigated the effects of neuropeptides and hBMP2 on gap junction intercellular communication (GJIC). Osteoblasts were treated with neuropeptide Y (NPY), substance P (SP), or hBMP2 at three concentrations. At various intervals after treatment, cell viability was measured by the MTT assay. In addition, cellular alkaline phosphatase (ALP) activity and osteocalcin were determined by colorimetric assay and radioimmunoassay, respectively. The effects of NPY, SP and hBMP on GJIC were determined by laser scanning confocal microscopy. The viability of cells treated with neuropeptides and hBMP2 increased significantly in a time-dependent manner, but was inversely associated with the concentration of the treatments. ALP activity and osteocalcin were both reduced in osteoblasts exposed to the combination of neuropeptides and hBMP2. The GJIC of osteoblasts was significantly increased by the neuropeptides and hBMP2. These results suggest that osteoblast activity is increased by neuropeptides and hBMP2 through increased GJIC. Identification of the GJIC-mediated signal transduction capable of modulating the cellular activities of bone cells represents a novel approach to studying the biology of skeletal innervation.

A spatial model showing differences between juxtacrine and paracrine mutual oocyte-granulosa cells interactions.

The bidirectional communication between oocytes and granulosa cells are mediated by several factors via a local feedback loop(s). The current model was carried out to study the spatial mutual interaction of porcine denuded oocytes and granulosa cells either in direct contact (juxtacrine) or paracrine co-culture using transwell system. Transwell 0.4 µm polyester membrane inserts were used to permit oocytes-granulosa cells paracrine communication with a distance of 2 mm between them in co-culture. Oocytes were cultured with granulosa cells in a defined basic maturation medium for 44 h. In results, oocyte secreted factors (OSFs; GDF9 and BMP15) temporal expression showed progressive decrement by the end of culture in case of direct contact with granulosa cells while it was increased progressively in the paracrine co-culture groups. However, oocytes that were cultured in direct contact showed a significant increase in blastocyst development after parthenogenetic activation than the paracrine co-cultured ones (20% vs. 11.5%, respectively). By the end of culture, granulosa cell count in direct contact showed a significant decrease than the indirect co-culture group (1.2 × 105 cell/mL vs. 2.1 × 105 cell/mL, respectively). Steroids (P4 and E2) and steriodogenesis enzymes mRNA levels showed significant temporal alterations either after 22 h and 44 h of IVM in both juxtacrine and paracrine co-culture systems (P ≤ 0.05). CX43 was much more highly expressed in the granulosa of the direct contact group than the indirect co-culture group. These results indicate the difference in mutual communication between oocytes and granulosa cells that were cocultured either in direct contact (juxtacrine) or with a short distance (paracrine) and propose a new paradigm to study different ovarian follicular cells interaction.

A low-protein diet during pregnancy prevents modifications in intercellular communication proteins in rat islets

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Inhibition of gap junctional intercellular communication protects astrocytes from hypoxia/reoxygenation injury / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of inhibiting gap junctional intercellular communication on hypoxia/reoxygenation injury in astrocytes.</p><p><b>METHODS</b>Primary cultured cerebral cortical astrocytes of neonate rats were divided into normal control group, hypoxia reoxygenation injury group and 18-α-glycyrrhetinic acid and oleamide (gap junctional intercellular channel inhibitors) group. The gap junction intercellular communication was determined by Parachute assay. The viability of astrocyes was detected by MTT assay. The apoptosis of astrocytes were detected with annexin V/PI and Hoechst 33258 staining.</p><p><b>RESULTS</b>Compared with the normal control group, the gap junctional function of astrocytes was increased significantly in ischemia/reperfusion group (P<0.01), the surviving fraction of astrocytes decreased significantly (P<0.01) and its cell apoptosis ratio increased significantly (P<0.01). Compared with the ischemia/reperfusion group, the gap junctional function of astrocytes in18-α-glycyrrhetinic acid and oleamide group decreased significantly (P<0.01), the viability of astrocytes increased significantly (P<0.01), while cell apoptosis decreased significantly (P<0.01).</p><p><b>CONCLUSION</b>Inhibition of intercellular gap junction has protective effect against hypoxia/reoxygenation injury in astrocytes.</p>

Cordblood-Based High-Throughput Screening for Deafness Gene of 646 Newborns in Jinan Area of China

OBJECTIVES: Infants with slight/mild or late-onset hearing impairment might be missed in universal newborn hearing screening (UNHS). We identified the mutation hot spot of common deaf gene in the newborns in Jinan area population by screening the mutation spot with neonate cord blood, in order to make clear whether the neonate cord blood for screening is feasible. METHODS: Six hundred and forty-six newborns were subjected to both UNHS and genetic screening for deafness by using neonate cord blood. The newborn genetic screening targeted four deafness-associated genes, which were commonly found in the Chinese population including gap junction beta-2 protein (GJB2), gap junction beta-3 protein (GJB3), solute carrier family 26 member 4 (SLC26A4), and mtDNA 12S rRNA. The most common 20 spot mutations in 4 deaf genes were detected by MassARRAY iPLEX platform and mitochondrial 12S rRNA A1555G and C1494T mutations were sequenced using Sanger sequencing. RESULTS: Among the 646 newborns, 635 cases passed the UNHS and the other 11 cases (1.7%) did not. Of the 11 failures, two cases were found to carry homozygous GJB2 p.R143W pathogenic mutation, one case was found to have heterozygous GJB2 235delC mutation, and another one case carried heterozygous GJB3 p.R180X pathogenic mutation. Six hundred and thirty-five babies passed the newborn hearing screening, in which 25 babies were identified to carry pathogenic mutations, including 12 heterozygotes (1.9%) for GJB2 235delC, eight heterozygotes (1.3%) for SLC26A4 IVS7-2A>G, one heterozygote (0.2%) for p.R409H, two homozygotes (0.3%) for m.1494C>T, and two homozygotes (0.3%) for m.1555A>G. CONCLUSION: Newborn genetic screening through the umbilical cord blood for common deafness-associated mutations may identify carriers sensitive to aminoglycoside antibiotic, and can effectively prevent or delay hearing loss occurs.