Calcium/calcimimetic via calcium-sensing receptor ameliorates cholera toxin-induced secretory diarrhea in mice

BACKGROUND Enterotoxins produce diarrhea through direct epithelial action and indirectly by activating the enteric nervous system.Calcium-sensing receptor(CaSR)inhibits both actions.The latter has been well documented in vitro but not in vivo.The hypothesis to be tested was that activating CaSR inhibits diarrhea in vivo.AIM To determine whether CaSR agonists ameliorate secretory diarrhea evoked by cholera toxin(CTX)in mice.METHODS CTX was given orally to C57BL/6 mice to induce diarrhea.Calcium and calci-mimetic R568 were used to activate CaSR.To maximize their local intestinal actions,calcium was administered luminally via oral rehydration solution(ORS),whereas R568 was applied serosally using an intraperitoneal route.To verify that their actions resulted from the intestine,effects were also examined on Cre-lox intestine-specific CaSR knockouts.Diarrhea outcome was measured biochemically by monitoring changes in fecal Cl-or clinically by assessing stool consistency and weight loss.RESULTS CTX induced secretory diarrhea,as evidenced by increases in fecal Cl-,stool consistency,and weight loss following CTX exposure,but did not alter CaSR,neither in content nor in function.Accordingly,calcium and R568 were each able to ameliorate diarrhea when applied to diseased intestines.Intestinal CaSR involvement is suggested by gene knockout experiments where the anti-diarrheal actions of R568 were lost in intestinal epithelial CaSR knockouts(villinCre/Casrflox/flox)and neuronal CaSR knockouts(nestinCre/Casrflox/flox).CONCLUSION Treatment of acute secretory diarrheas remains a global challenge.Despite advances in diarrhea research,few have been made in the realm of diarrhea therapeutics.ORS therapy has remained the standard of care,although it does not halt the losses of intestinal fluid and ions caused by pathogens.There is no cost-effective therapeutic for diarrhea.This and other studies suggest that adding calcium to ORS or using calcimimetics to activate intestinal CaSR might represent a novel approach for treating secretory diarrheal diseases.

Calcium-sensing receptor in colorectal inflammation and cancer:Current insights and future perspectives

The extracellular calcium-sensing receptor(CaSR) is best known for its action in the parathyroid gland and kidneys where it controls body calcium homeostasis. However, the CaSR has different roles in the gastrointestinal tract, where it is ubiquitously expressed. In the colon, the CaSR is involved in controlling multiple mechanisms, including fluid transport, inflammation, cell proliferation and differentiation. Although the expression pattern and functions of the CaSR in the colonic microenvironment are far from being completely understood, evidence has been accumulating that the Ca SR might play a protective role against both colonic inflammation and colorectal cancer. For example, CaSR agonists such as dipeptides have been suggested to reduce colonic inflammation, while dietary calcium was shown to reduce the risk of colorectal cancer. CaSR expression is lost in colonic malignancies, indicating that the CaSR is a biomarker for colonic cancer progression. This dual anti-inflammatory and anti-tumourigenic role of the CaSR makes it especially interesting in colitisassociated colorectal cancer. In this review, we describe the clinical and experimental evidence for the role of the CaSR in colonic inflammation and colorectal cancer, the intracellular signalling pathways which are putatively involved in these actions, and the possibilities to exploit these actions of the CaSR for future therapies of colonic inflammation and cancer.

Antagonizing amyloid-β/calcium-sensing receptor signaling in human astrocytes and neurons: a key to halt Alzheimer's disease progression?

Astrocytes＇ roles in late-onset Alzheimer＇s disease （LOAD） promotion are important, since they survive soluble or fibrillar amyloid-β peptides （Aβs） neurotoxic effects, undergo alterations of intracellular and intercellular Ca2＋ signaling and gliotransmitters release via the Aβ/a7-nAChR （αT-nicotinic acetylcholine receptor） signaling, and overproduce/oversecrete newly synthesized Aβ42 oligomers, NO, and VEGF-A via the Aβ/CaSR （calcium-sensing receptor） signaling. Recently, it was suggested that the NMDAR （N-methyl-D-aspartate receptor） inhibitor nitromemantine would block the synapse-destroying effects of Aβ/α7-nAChR signaling. Yet, this and the progressive extracellular accrual and spreading of Aβ42 oligomers would be stopped well upstream by NPS 2143, an allosteric CaSR antagonist （calcilytic）.

Calcium-Sensing Receptor of Immune Cells and Diseases

Calcium-sensing receptor(CaSR),which was initially found in the parathyroid gland,is ubiquitously expressed and exerts specifi c functions in multiple cells,including immune cells.CaSR is functionally expressed on neutrophils,monocytes/macrophages,and T lymphocytes,but not B lymphocytes,and regulates cell functions,such as cytokine secretion,chemotaxis,phenotype switching,and ligand delivery.In these immune cells,CaSR is involved in the development of many diseases,such as sepsis,cryopyrin-associated periodic syndromes,rheumatism,myocardial infarction,diabetes,and peripheral artery disease.Since its discovery,it has been controversial whether CaSR is expressed and plays a role in immune cells.This article reviews current knowledge of the role of CaSR in immune cells.

Phenytoin-Induced Elevation of the Intracellular Calcium Concentration by Stimulation of Calcium-Sensing Receptors in Gingival Fibroblasts

Background:The mechanism concerning gingival overgrowth as a side effect of phenytoin, a therapeutic drug for epilepsy has been still unclear. As one of mechanisms, by measuring the intracellular calcium concentration ([Ca2+]i) of the gingival fibroblasts, it has been advocated that there is relationship between gingival overgrowth and phenytoin-induced alterations in the [Ca2+]i in gingival fibroblasts. To confirm that phenytoin elevates the [Ca2+]i, and if so, to find out its mode of action. Methods: The [Ca2+]i was measured with the Ca2+-sensitive fluorescent dye fura-2/AM. Cells were soaked in a flexiperm chamber and perfused by a saline. Drugs at appropriate concentrations were added to the perfusate. Results: Phenytoin concentration-dependently elevated the [Ca2+]i. NPS2390, a calcium-sensing receptor (CaSR) blocker, significantly suppressed the phenytoin-induced [Ca2+]i elevation. U73122, a phospholipase C (PLC) inhibitor, inihibited the phenytoin-induced [Ca2+]i elevation. TMB-8, a blocker of inositol triphophate (IP3) receptors in ER, significantly depressed the phenytoin-induced [Ca2+]i elevation. m-3M3FBS, a PLC activator, enhanced the phenytoin-induced [Ca2+]i elevation. From the findings obtained, it is discussed as follows: The Ca2+-free saline and NPS2390, a CaSR antagonist, inhibited the phenytoin-induced [Ca2+]i rise;These results indicate that CaSRs exist in gingival fibroblasts and that CaSRs are involved in the phenytoin-induced [Ca2+]i rise;U73122 and TMB-8 depressed the phenytoin-induced [Ca2+]i elevation and furthermore, m-3M3FBS enhanced the phenytoin-induced [Ca2+]i elevation, showing that the Ca2+ release from the ER is involved in the phenytoin-induced [Ca2+]i elevation. Conclusion: We have concluded that phenytoin elevates the [Ca2+]i by activating CaSRs and enhancing the Ca2+ release from the Ca2+ stores in gingival fibroblasts.

Enzyme-linked Immunosorbent Assay for Detection of Anti-idiotype Antibodies to Antibodies to Ligand of Nicotinic Acetylcholine Receptor in Sera of Patients with Myasthenia Gravis

Anti-bungarotoxin anti-serum,which has the internal image of nicotinicacetylcholine receptor,was used as a tool to measure anti-idiotypic antibodies toantibodies to Iigand of nicotinic acctylcholine receptor in scra from 81 patients withmyasthenia gravis.Enzyme-linked immunosorbcnt assay was adopted.Thc positive ratewas 46.9%(38/81).The specific cross inhibitory test with nicotinic acetylcholinereceptor was positive.Anti-idiotype antibodies to antibodies to ligand of nicotinicacetylcholine receptor in sera of different types of myasthenia gravis patients classified ac-cording to modified Osserman’s standard and myasthenia gravis patients with or withoutthymoma were comparcd in this study and the role of anti-idiotype antibodies toantibodies to Iigand of nicotinic acctylcholinc receptor in the immunity of myasthcniagravis and the possibility of thcrapeutic use of anti-idiotype antibodies arc discussed.

Fluorescence Resonance Energy Transfer Competitive Binding Assay for Secretin Receptor （Class B-GPCR）

Human secretin is responsible for carrying a number of physiological functions including energy and water homeostasis, thus making secretin receptor a promising target for drug development. For GPCRs （G protein-coupled receptors）, radioactive ligands are usually used in conventional binding assays to characterize the binding affinities of the ligands. An alternative non-hazardous fluorescence based binding assay is lucrative over the radio-ligand assays. Here, we have developed a FRET （fluorescence resonance energy transfer） competitive binding assay for human secretin receptor. The receptor gene sequence is cloned in the SNAP （single nucleotide amplified polymorphisms） tag-plasmid and expressed in CHO （chinese hamster ovary）-K1 cells. Its expression and function is confirmed with immunofluorescence localization and receptor activation. The receptor and the ligand are labeled with fluorescent donor （Tb） and acceptor （Alexa488）. FRET signals are produced when the labeled ligand is bound to the receptor and the same drop when it is displaced by the test compounds. The saturation concentration of the receptor labeling is 100 nM, and the ligand Kd value is 500 nM. At these concentrations, the IC50 of unlabeled secretin is 1.63 4- 3.55 nM. Additionally, few class-B ligands are screened and hold good correlation with traditional radio-ligand assay. Henceforth, this FRET binding assay can be efficiently used as a primary screening tool for peptide analogs.

Neurosyphilis complicated by anti-γ-aminobutyric acid-B receptor encephalitis: A case report

BACKGROUND Syphilis is an infectious disease caused by Treponema pallidum that can invade the central nervous system,causing encephalitis.Few cases of anti-N-methyl-Daspartate receptor autoimmune encephalitis(AE)secondary to neurosyphilis have been reported.We report a neurosyphilis patient with anti-γ-aminobutyric acid-B receptor(GABABR)AE.CASE SUMMARY A young man in his 30s who presented with acute epileptic status was admitted to a local hospital.He was diagnosed with neurosyphilis,according to serum and cerebrospinal fluid(CSF)tests for syphilis.After 14 d of antiepileptic treatment and anti-Treponema pallidum therapy with penicillin,epilepsy was controlled but serious cognitive impairment,behavioral,and serious psychiatric symptoms were observed.He was then transferred to our hospital.The Mini-Mental State Examination(MMSE)crude test results showed only 2 points.Cranial magnetic resonance imaging revealed significant cerebral atrophy and multiple fluidattenuated inversion recovery high signals in the white matter surrounding both lateral ventricles,left amygdala and bilateral thalami.Anti-GABABR antibodies were discovered in CSF(1:3.2)and serum(1:100).The patient was diagnosed with neurosyphilis complicated by anti-GABABR AE,and received methylprednisolone and penicillin.Following treatment,his mental symptoms were alleviated.Cognitive impairment was significantly improved,with a MMSE of 8 points.Serum anti-GABABR antibody titer decreased to 1:32.The patient received methylprednisolone and penicillin after discharge.Three months later,the patient’s condition was stable,but the serum anti-GABABR antibody titer was 1:100.CONCLUSION This patient with neurosyphilis combined with anti-GABABR encephalitis benefited from immunotherapy.

Molecular regulation of calcium-sensing receptor(CaSR)-mediated signaling

Calcium-sensing receptor(CaSR),a family C G-protein-coupled receptor,plays a crucial role in regulating calcium homeostasis by sensing small concentration changes of extracellular Ca^(2+),Mg^(2+),amino acids(e.g.,L-Trp and L-Phe),small peptides,anions(e.g.,HCO_(3)^(-)and PO_(4)^(3-)),and pH.CaSR-mediated intracellular Ca^(2+)signaling regulates a diverse set of cellular processes including gene transcription,cell proliferation,differentiation,apoptosis,muscle contraction,and neuronal transmission.Dysfunction of CaSR with mutations results in diseases such as autosomal dominant hypocalcemia,familial hypocalciuric hypercalcemia,and neonatal severe hyperparathyroidism.CaSR also influences calciotropic disorders,such as osteoporosis,and noncalciotropic disorders,such as cancer,Alzheimer's disease,and pulmonary arterial hypertension.This study first reviews recent advances in biochemical and structural determination of the framework of CaSR and its interaction sites with natural ligands,as well as exogenous positive allosteric modulators and negative allosteric modulators.The establishment of the first CaSR protein-protein interactome network revealed 94 novel players involved in protein processing in endoplasmic reticulum,trafficking,cell surface expression,endocytosis,degradation,and signaling pathways.The roles of these proteins in Ca^(2+)-dependent cellular physiological processes and in CaSR-dependent cellular signaling provide new insights into the molecular basis of diseases caused by CaSR mutations and dysregulated CaSR activity caused by its protein interactors and facilitate the design of therapeutic agents that target CaSR and other family C G-protein-coupled receptors.

Optogenetics-induced activation of glutamate receptors improves memory function in mice with Alzheimer’s disease

Optogenetics is a combination of optics and genetics technology that can be used to activate or inhibit specific cells in tissues. It has been used to treat Parkinson’s disease, epilepsy and neurological diseases, but rarely Alzheimer’s disease. Adeno-associated virus carrying the CaMK promoter driving the optogenetic channelrhodopsin-2 (CHR2) gene (or without the CHR2 gene, as control) was injected into the bilateral dentate gyri, followed by repeated intrahippocampal injections of soluble low-molecular-weight amyloid-β1–42 peptide (Aβ1–42). Subsequently, the region was stimulated with a 473 nm laser (1–3 ms, 10 Hz, 5 minutes). The novel object recognition test was conducted to test memory function in mice. Immunohistochemical staining was performed to analyze the numbers of NeuN and synapsin Ia/b-positive cells in the hippocampus. Western blot assay was carried out to analyze the expression levels of glial fibrillary acidic protein, NeuN, synapsin Ia/b, metabotropic glutamate receptor-1a (mGluR-1a), mGluR-5, N-methyl-D-aspartate receptor subunit NR1, glutamate receptor 2, interleukin-1β, interleukin-6 and interleukin-10. Optogenetic stimulation improved working and short-term memory in mice with Alzheimer’s disease. This neuroprotective effect was associated with increased expression of NR1, glutamate receptor 2 and mGluR-5 in the hippocampus, and decreased expression of glial fibrillary acidic protein and interleukin-6. Our results show that optogenetics can be used to regulate the neuronal-glial network to ameliorate memory functions in mice with Alzheimer’s disease. The study was approved by the Animal Resources Committee of Jinan University, China (approval No. LL-KT-2011134) on February 28, 2011.

Estrogen affects neuropathic pain through upregulating N-methyl-D-aspartate acid receptor 1 expression in the dorsal root ganglion of rats

Estrogen affects the generation and transmission of neuropathic pain,but the specific regulatory mechanism is still unclear.Activation of the N-methyl-D-aspartate acid receptor 1（NMDAR1） plays an important role in the production and maintenance of hyperalgesia and allodynia.The present study was conducted to determine whether a relationship exists between estrogen and NMDAR1 in peripheral nerve pain.A chronic sciatic nerve constriction injury model of chronic neuropathic pain was established in rats.These rats were then subcutaneously injected with 17β-estradiol,the NMDAR1 antagonist D（-）-2-amino-5-phosphonopentanoic acid（AP-5）,or both once daily for 15 days.Compared with injured drug na？ve rats,rats with chronic sciatic nerve injury that were administered estradiol showed a lower paw withdrawal mechanical threshold and a shorter paw withdrawal thermal latency,indicating increased sensitivity to mechanical and thermal pain.Estrogen administration was also associated with increased expression of NMDAR1 immunoreactivity（as assessed by immunohistochemistry） and protein（as determined by western blot assay） in spinal dorsal root ganglia.This 17β-estradiol-induced increase in NMDAR1 expression was blocked by co-administration with AP-5,whereas AP-5 alone did not affect NMDAR1 expression.These results suggest that 17β-estradiol administration significantly reduced mechanical and thermal pain thresholds in rats with chronic constriction of the sciatic nerve,and that the mechanism for this increased sensitivity may be related to the upregulation of NMDAR1 expression in dorsal root ganglia.

DETERMINATION OF SERUM SOLUBLE MACROPHAGE COLONY-STIMULATING FACTOR RECEPTOR LEVELS IN PATIENTS WITH HEMATOLOGICAL DISEASES

Objective: To investigate the serum levels of soluble macrophage colony-stimulating factor receptor (M-CSFsR) in normal subjects and patients with hematological diseases and its clinical implications in hematological diseases. Methods: The concentration of M-CSFsR was determined by ELISA. The serum M-CSFsR was identified and characterized by immunoprecipitation and Western blotting. Results: The mean serum level of M-CSFsR of 123 normal individuals was 0.48 ng/ml ± 0.41 ng/ml. Immunoprecipitation and Western blotting assay revealed a ～ 90kD band of serum M-CSFsR. The mean serum M-CSFsR level of 60 patients with acute lymphoblastic leukemia (ALL), 36 patients with acute myeloblastic leukemia (AML), 13 patients with myelodysplastic syndrome (MDS) and 42 patients with aplastic anemia (AA) .were 0.22 ng/ml±0.23 ng/ml, 0.17 ng/ml±0.16 ng/ml, 0.19 ng/ml±0.16 ng/ml and 0.23 ng/ml±0.21 ng/ml, respectively, which were significantly lower than that of normal subjects (P=0.002 ,P<0.0001,P<0.0001 andP<0.0001). The mean serum M-CSFsR level of 51 idiopathic thrombocytopenic purpura (ITP) patients was significantly higher than that of normal subjects (2.05 ng/ml±2.75 ng/ml,P<0.0001). Conclusion: The serum M-CSFsR levels of patients with ALL, AML, MDS and AA were significantly lower, while the level of patients with ITP was significantly higher than that of normal individuals. Patients with severe ITP (platelet count<30×l09/L) had the highest M-CSFsR level. It suggested that the abnormal levels of serum M-CSFsR may associate with some hematological diseases and may contribute to the pathological process.

Canine Distemper Virus Utilizes Different Receptors to Infect Chicken Embryo Fibroblasts and Vero cells

Inducing animal viruses to adapt to chicken embryos or chicken embryo fibroblasts(CEF) is a common method to develop attenuated live vaccines with full security.Canine distemper virus(CDV) also does this,but the mechanisms and particular receptors remain unclear.Virus overlay protein blot assays were carried out on CEF membrane proteins,which were extracted respectively with a Mem-PER TM kit,a radioimmunoprecipitation assay buffer or a modified co-immunoprecipitation method,and revealed a common 57 kDa positive band that differed from the 42-kDa positive band in Vero cells and also from those receptors reported in lymphocytes and 293 cells,indicating a receptor diversity of CDV and the possibility of the 57-kDa protein acting as a receptor that is involved in adaptive infection of CDV Kunming strain to CEF.

Modulation of the activation of Statl by the interferon-gamma receptor complex

The activation of Statl by the interferon-gamma （IFN-γ） receptor complex is responsible for the transcription of a significant portion of IFN-γ induced genes. Many of these genes are responsible for the induction of an apoptotic state in response to IFN-γ. In the absence of Stat 1 activation, IFN-γ instead induces a proliferative response. Modifying Stat 1 activation by IFN-γ may have pharmacological benefits. We report that the rate of activation of Statl can be altered in HeLa cells by overexpressing either the IFN-γ R1 chain or the IFN-γ R2 chain. These alterations occur in hematopoietic cell lines： Raji cells and monocytic cell lines, which have average and above-average IFN-γ R2 surface expression, activate Statl similarly to HeLa cells and HeLa cells overexpressing IFNγR2, respectively. The rapid Statl activation seen in HeLa cells can be inhibited by overexpressing a chimeric IFN-γR2 chain that does not bind Jak2 or （when high concentrations of IFN-γ are used） by overexpressing IFN-γR1. These data are consistent with a model in which the recruitment of additional Jak2 activity to a signaling complex accelerates the rate of Statl activation. We conclude that the rate of activation of Statl in cells by IFN-γ can be modified by regulating either receptor chain and speculate that pharmacological agents which modify receptor chain expression may alter IFN-γ receptor signal transduction.

Evaluation of a novel angiotensin II receptor 1 antagonist intesartan as anti-hypertension drug

Aim The preclinical studies of a novel angiotensin II receptor 1 antagonist 2-（4-（ （1,7＇-dimethyl-2＇- propyl-1H ,3 ＇H-2,5＇-bibenzo [ d ] imidazol-3＇-yl ） methyl） -1H-indol-l-yl ） benzoic acid （ intesartan ）. Methods The affinity to AT1 receptor of intesartan was tested through radioactive receptor binding assay by -y-counter. The anti-hypertensive activity in spontaneously hypertensive rats （SHRs） at different doses in vivo was tested by tail noninvasive arterial blood pressure measurement system. Pharmacokinetic parameters were analyzed by high per- formance liquid chromatography （HPLC） method. Besides, acute toxicity tests in ICR and Ames reverse mutation assay in tester strain （TA97, TA98, TA100 and TA102） was also detected. Results The binding assays sugges- ted that intesartan displayed high affinity to angiotensin II AT1 receptor with an ICs0 value of （0.36 ± 0. 18） nmol · L^-1. In vivo anti-hypertensive experiments showed that intesartan had an efficient and long-acting effect in reduc- ing blood pressure which could last more than 24 h at the doses of 2 mg· kg^-1, 5 mg · kg^-1 , and 10 mg · kg^-1 in spontaneously hypertensive rats. The minimum effective dose of it was 2 mg · kg^-1 and the T/P value was 54. 18%. Acute toxicity tests suggested that intesartan was safe with the LDs0 value of 526.20 mg · kg^-1. Ames assay proved that it would not cause the mutations of salmonella typhimurium. And the pharmacokinetic experiments showed that it could be absorbed efficiently and metabolized smoothly both in blood and in tissues in wistar rats. Conclusions Intesartan could be considered as a novel anti-hypertension candidate with efficient, long-acting and low toxicity chracteristics.

Comparative study on the properties ofMDA－LDL＇s and o－LDL＇s receptors on macrophage

By means of radioligand binding assay, both receptors of the malondialdehyde modified low density lipoprotein (MDA-LDL) and the oxidatively modified LDL(o-LDL) on the mouse's peritoneal macrophage (MPM) were studied. The results show that there were high affinity receptors for MDA-LDL and o-LDL on the MPM and both receptors had multiplicity of configuration based on the competitive-inhibition curve or parameters IC50 and Ki, and the acetylated LDL (Ac-LDL) and dextran sulfate can both competitively inhibit MDA-LDL or oLDL binding to these receptors in some degree.It is meanful to study the scavenger receptor multiplicity and its relationship to the genesis, protection and treamtent of atherosclerosis.

A Quantitative Study on Vascular Angiotensin Ⅱ Receptors in Rats with Portal Hypertension

Angiotension-Ⅱ(A-Ⅱ) receptor maximal binding capacity (Bmax) and dissociation constants (Kd) of different blood vessels in rats with prehepatic portal hypertension were studied by radioligand binding analysis. The results showed that the A-Ⅱreceptor Bmax. in the thoracic aorta, superior mesenteric artery and portal vein of portal hypertensive animals (113. 7±19. 4 fmol/mg protein, 206.9 ±39. 3 fmol/mg protein and 31. 5±9. 2 fmol/mg protein respectively ) was all significantly lower than that of controls (146. 8±24. 5 fmol/mg protein, 297. 2±44. 7 fmol/mg protein and 53. 4±12.1 fmol/mg protein respectively, P＜0. 01).The A-Ⅱ receptor Kd in the superior mesenteric artery was markedly increased in portal hypertensive animals (1. 03±0.11 nmol/L) compared with that in controls (0. 88±0. 08 nmol/L, P＜0. 05). In the thoracic aorta and portal vein, the A-Ⅱ receptor Kd in portal hypertensive animals was slightly higher than that in controls, but no significant difference was observed between the two groups. The results suggested that the vascular hyporesponsiveness to A-Ⅱ in portal hypertension was caused partially by a reduction in number and a decrease in affinity of vascular A- Ⅱ receptors, and these changes might possibly lead to the formation of hyperdynamic circulation.

The calcium-sensing receptor participates in testicular damage in streptozotocin-induced diabetic rats

Male infertility caused by testicular damage is one of the complications of diabetes mellitus. The calcium-sensing receptor （CaSR） is expressed in testicular tissues and plays a pivotal role in calcium homeostasis by activating cellular signaling pathways, but its role in testicular damage induced by diabetes remains unclear. A diabetic model was established by a single intraperitoneal injection of streptozotocin （STZ, 40 mg kg-1） in Wistar rats. Animals then received GdCl3 （an agonist of CaSR, 8.67 mg kg-1）, NPS-2390 （an antagonist of CaSR, 0.20 g kg-~）, or a combination of both 2 months after STZ injection. Diabetic rats had significantly lower testes weights and serum levels of testosterone compared to healthy rats, indicating testicular damage and dysfunction in STZ-induced diabetic rats. Compared with healthy controls, the testicular tissues of diabetic rats overexpressed the CaSR protein and had higher levels of malondialdehyde （MDA）, lower superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） activity, and higher numbers of apoptotic germ cells. The testicular tissues from diabetic rats also expressed lower levels of Bcl-2 and higher levels of Bax and cleaved caspase-3 in addition to higher phosphorylation rates of c-Jun NH2-terminal protein kinase （JNK）, p38, and extracellular signaling-regulated kinase （ERK） 1/2. The above parameters could be further increased or aggravated by the administration of GdCI3, but could be attenuated by injection of NPS-2390. In conclusion, the present results indicate that CaSR activation participates in diabetes-induced testicular damage, implying CaSR may be a potential target for protective strategies against diabetes-induced testicular damage and could help to prevent infertility in diabetic men.

小立碗藓CAS基因的克隆及与拟南芥CAS基因的比较

钙信号在动植物的生长、发育过程中具有不可替代的作用.胞外钙受体(Extracellular Calcium-sensing receptor,CAS)是动植物质膜上一种跨膜离子通道蛋白,可以感受胞外Ca2+水平,充当第一信使将胞外的信号传递到细胞内.但迄今为止,仅2003年从植物拟南芥中克隆了胞外钙受体CAS基因,其起源进化我们知之甚少.本实验成功克隆了小立碗藓CAS基因,其cDNA全序列共1 574 bp,5′-非翻译区80个核苷酸,3′-非翻译区234个核苷酸,开放阅读框(ORF)1 257 bp,编码419个氨基酸,共有6个内含子.虽然藓类植物与被子植物进化距离较远,但小立碗藓CAS基因前五个内含子的插入位置以及相位与拟南芥完全相同,这说明植物中CAS基因在漫长的进化过程中非常保守,暗示被子植物胞外钙离子信号感受、传递机制起源于藓类植物.

鼻息肉组织中T淋巴细胞功能的研究

鼻息肉是多因素引发和介导的一种炎症性疾病（[1]）,多种炎性细胞浸润是其主要病理学特征（[2]）。我们前期的研究发现,鼻息肉组织中可见大量树突状细胞浸润[3],树突状细胞将抗原递呈给T淋巴细胞后,两者通过一系列的相互作用,介导免疫反应,而T细胞的分化失衡在鼻息肉发病过程中起到关键性作用（[4]）。然而,鼻息肉组织中T淋巴细胞的功能状态目前尚不明确。