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Biomedical subjects

W W Lin

Publications and source records attributed to W W Lin.

At least 37 records · Page 2Linked to original sources
PubMed1999

Enhanced mRNA expression of neurofilament subunits in the brain and spinal cord of diisopropyl phosphorofluoridate-treated hens.

Diisopropyl phosphorofluoridate (DFP) is an organophosphorus ester, and a single injection of this compound (1.7 mg/kg, s.c.) produces delayed neurotoxicity (OPIDN) in hens in 7-14 days. Clinically, the disease is marked by hindlimb ataxia followed by paralysis after some time. A characteristic feature of this neuropathy is axonal swelling in the initial stages and comparative dissolution of the accumulated material and degeneration of distal axons with disease progression. Axonal swelling consists of aggregated neurofilaments, microtubules, and proliferated smooth endoplasmic reticulum. We studied expression of neurofilament (NF) mRNAs in brain regions and spinal cord to elucidate their role in OPIDN. There was a 50-200% increase in NF transcripts in 24 hr after DFP administration. The NF-L mRNA level started falling after 1-5 days and came down to control level in susceptible brain regions (i.e. cerebellum and brainstem) and spinal cord, but not in cerebral cortex, which does not show degeneration of axons in OPIDN. Cerebral cortex exhibited elevated levels of both NF-L and NF-M transcripts in DFP-treated hens throughout the period of observation. The induction of NF messages is consistent with the previously reported effect on extension of neurites of human neuroblastoma cells in culture. The transient increase in NF messages in susceptible tissues either may be responsible for the delayed degeneration of axons in OPIDN or is the result of interruption of regulatory signal due to progressive degeneration of axons.

Animals↗
PubMed1999

Protein kinase C epsilon-dependent pathway of extracellular signal-regulated protein kinase activation by P2Y1 and P2Y2 purinoceptors that activate cytosolic phospholipase A2 in endothelial cells.

The aim of this study was to investigate the stimulating effects on arachidonic acid release of P2Y1 and P2Y2 receptor-selective agonists, 2-methylthio-ATP (2MeSATP) and UTP, respectively, in bovine pulmonary artery endothelial cells. Exposure of cells to 2MeSATP and UTP led to the release of arachidonic acid, a response which was abolished by the removal of extracellular Ca2+ and methyl arachidonyl fluorophosphonate. Phorbol 12-myristate 13-acetate (PMA) itself not only stimulated arachidonic acid release but also played a permissive role in the response to UTP. However, PMA failed to enhance the arachidonic acid response induced by 2MeSATP, probably due to greater attenuation of the [Ca2+]i increase caused by 2MeSATP than UTP. Inhibition of protein kinase C with Ro 31-8220 (1-[3-(amidinothio) propyl-1H-indoyl-3-yl]-3-(1-methyl-1H-indoyl-3-yl)-maleimide -methane sulphate) and staurosporine, but not with Go 6976 (12-(-2-cyanoethyl)-6,7,12,13-tetrahydro-13-methyl-5-oxo-indolo(2, 3-a)pyrrolo(3,4-c)carbazole), reduced the arachidonic acid response of 2MeSATP, UTP and PMA. PMA-induced potentiation of the UTP response reached a maximum after a 1-h preincubation, then declined and eventually lost its effect when the preincubation lasted up to 8 h. Among the protein kinase C isoforms present in endothelial cells, betaI and epsilon could be down-regulated by treatment with PMA for 4-24 h. PD 098059 (2-(2-Amino-3-methoxyphenyl)-4H-1-benzopyran-4-one) inhibited extracellular signal-regulated protein kinase activation, cytosolic phospholipase A2 phosphorylation and arachidonic acid release caused by 2MeSATP, UTP and PMA. Taken together, our results demonstrate that P2Y1 and P2Y2 purinoceptors mediate arachidonic acid release by activating cytosolic phospholipase A2 through an elevation of [Ca2+]i and protein kinase C epsilon-, extracellular signal-regulated protein kinase-dependent phosphorylation.

Adenosine Triphosphate↗
PubMed1999

Molecular enzymology of mammalian Delta1-pyrroline-5-carboxylate synthase. Alternative splice donor utilization generates isoforms with different sensitivity to ornithine inhibition.

Delta1-Pyrroline-5-carboxylate synthase (P5CS; EC not assigned), a mitochondrial inner membrane, ATP- and NADPH-dependent, bifunctional enzyme, catalyzes the reduction of glutamate to Delta1-pyrroline-5-carboxylate, a critical step in the de novo biosynthesis of proline and ornithine. We utilized published plant P5CS sequence to search the expressed sequence tag data base and cloned two full-length human P5CS cDNAs differing in length by 6 base pairs (bp) in the open reading frame. The short cDNA has a 2379-bp open reading frame encoding a protein of 793 residues; the long cDNA, generated by "exon sliding," a form of alternative splicing, contains an additional 6-bp insert following bp +711 of the short form resulting in inclusion of two additional amino acids in the region predicted to be the gamma-glutamyl kinase active site of P5CS. The long form predominates in all tissues examined except gut. We also isolated the corresponding long and short murine P5CS transcripts. To confirm the identity of the putative P5CS cDNAs, we expressed both human forms in gamma-glutamyl kinase- and gamma-glutamyl phosphate reductase-deficient strains of Saccharomyces cerevisiae and showed that they conferred the proline prototrophy. Additionally, we found expression of the murine putative P5CS cDNAs conferred proline prototrophy to P5CS-deficient Chinese hamster ovary cells (CHO-K1). We utilized stable CHO-K1 cell transformants to compare the biochemical characteristics of the long and short murine P5CS isoforms. We found that both confer P5CS activity and that the short isoform is inhibited by L-ornithine with a Ki of approximately 0.25 mM. Surprisingly, the long isoform is insensitive to ornithine inhibition. Thus, the two amino acid insert in the long isoform abolishes feedback inhibition of P5CS activity by L-ornithine.

1-Pyrroline-5-Carboxylate Dehydrogenase↗
PubMed1999

Modulation of inducible nitric oxide synthase induction by prostaglandin E2 in macrophages: distinct susceptibility in murine J774 and RAW 264.7 macrophages.

Prostaglandin E2 (PGE2) is the major cyclooxygenase metabolite in macrophages with complex proinflammatory and immunoregulatory properties. In the present study, we have compared the modulatory role of PGE2/cAMP-dependent signaling on induced nitric oxide (NO) production in two murine macrophages, J774 and RAW 264.7. With no effect on NO release by itself, PGE2 co-addition with lipopolysaccharide (LPS) resulted in a concentration-dependent enhancement in NO release and inducible NO synthase induction in J774, but not in RAW 264.7, macrophages. The potentiation effect of PGE2 in J774 cells was still seen when applied within 9 h after LPS treatment. Whereas RAW 264.7 macrophages release PGE2 with greater extent than J774 macrophages in response to LPS, indomethacin and NS-398, upon abolishing LPS-induced PGE2 release, caused a more obvious inhibition of NO release from J774 than RAW 264.7 cells. Thus, we suggest a higher positive modulatory role of PGE2--either endogenous or exogenous--on NO formation in J774 cells. Supporting these findings, exogenous PGE2 triggers cAMP formation in J774 cells with higher potency and efficacy. Of interest, dBcAMP also elicits higher sensitivity in potentiating NO release in J774 cells. We conclude that the opposite effect of PGE2/cAMP signaling on macrophage NO induction depends on its signaling efficacy and might be associated with the difference in endogenous PGE2 levels.

Animals↗
PubMed1999

The role of autosomal cell apoptosis regulator genes in human spermatogenesis.

Immunohistochemical analysis of the expression of the autosomal apoptosis regulator genes, BAX, bcl-2, p53, and cyclic-AMP responsive element modulator (CREM) in testis biopsies from infertile men demonstrated that BAX, bcl-2, and p53 immunoreactivity was absent irrespective of seminiferous tubule histology. In contrast, cell-specific CREM immunoreactivity in round spermatids, with complete absence of CREM in patient biopsies showing spermatocyte maturation arrest and Sertoli cell only, was evident, suggesting a possible role of autosomal genes in the regulation of apoptosis in human spermatogenesis regulation.

Adult↗
PubMed1999

Induction of cyclo-oxygenase-2 expression by methyl arachidonyl fluorophosphonate in murine J774 macrophages: roles of protein kinase C, ERKs and p38 MAPK.

1. Methyl arachidonyl fluorophosphonate (MAFP), an inhibitor of phospholipase A2 (PLA2), has been widely used to assess the roles of PLA2 in various cell functions. Here, we report on a novel action of this compound at concentrations similar to those used for PLA2 inhibition. 2. The murine macrophage J774 released a large amount of prostaglandin E2 (PGE2) by MAFP (1-30 microM), which was abolished by indomethacin and NS-398 but not by valeryl salicylate, and results from increased cyclo-oxygenase-2 (COX-2) protein levels and gene expression. 3. This PGE2 release was blocked by inhibitors of tyrosine kinase (genistein), protein kinase C (PKC) (Ro 31-8220, Go 6976 or LY 379196), mitogen-activated protein kinase kinase (MEK) (PD 098059) or p38 mitogen-activated protein kinase (MAPK) (SB 203580). 4. Consistent with these results, MAFP caused membrane translocation of PKCbetaI and betaII isoforms and activated extracellular signal-regulated kinase (ERK) and p38 MAPK. 5. In accordance with these effects of MAFP, PKC activator phorbol 12-myristate 13-acetate (PMA) increased PGE2 release and caused activation of PKCbeta, ERKs and p38 MAPK. 6. This is the first report that the PLA2 inhibitor, MAFP, can induce COX-2 gene expression and PGE2 synthesis via the PKC-, ERK- and p38 MAPK-dependent pathways. Thus, the use of MAFP as a PLA2 inhibitor should be treated with caution.

Animals↗
PubMed1999

PKCbetaI mediates the inhibition of P2Y receptor-induced inositol phosphate formation in endothelial cells.

1. Bovine pulmonary artery endothelium (CPAE) expresses phospholipase C (PLC)-linked P2Y1 and P2Y2 receptors, for them 2-methylthio-ATP (2MeSATP) and UTP are respective agonists. Here, we have investigated the particular protein kinase C (PKC) isoform(s) responsible for the inhibition of P2Y1 and P2Y2 receptor-evoked inositol phosphate (IP) formation by phorbol 12-myristate 13-acetate (PMA). 2. Although short-term (20 min) pretreatment of cells with PMA attenuated 2MeSATP- and UTP-induced phosphoinositide (PI) breakdown, this inhibition was lost after 15 h. Preincubation with PMA for 24 h, on the contrary, potentiated 2MeSATP and UTP responses. The IP formation stimulated by NaF was unaltered by PMA pretreatment. 3. Western blot analysis showed that treatment of CPAE with PMA resulted in a rapid translocation of PKC isoform betaI, epsilon and mu, but not lambda, from the cytosol to the membrane fraction. 4. Pretreatment of the selective PKC inhibitor Ro 31-8220 attenuated the inhibitory effect of PMA on IP formation. Go 6976 (an inhibitor of conventional PKCalpha, beta and gamma) and LY 379196 (a selective PKCbeta inhibitor) also dose-dependently inhibited the PMA-mediated desensitization. 5. Transfection of PKCbeta-specific antisense oligonucleotide reduced PKCbetaI protein level and inhibited PMA-mediated PI reduction. 6. RT - PCR analysis showed that PMA treatment for 4 - 24 h up-regulated P2Y1 and P2Y2 receptors at the mRNA levels. 7. These results suggest that PKCbetaI may exert a negative feedback regulation on endothelial P2Y1 and P2Y2 receptor-mediated PI turnover. The down-regulation of PKCbetaI and enhanced P2Y receptor expression together might contribute to the late PI enhancing effect of PMA.

Adenosine Triphosphate↗
PubMed1999

Roles of atypical protein kinase C in lysophosphatidic acid-induced type II adenylyl cyclase activation in RAW 264.7 macrophages.

1 Lysophosphatidic acid (LPA) has been widely studied as a naturally occurring and multifunctional phospholipid messenger in diverse tissue and cell types and shown to inhibit adenylyl cyclase (AC) by a G protein-mediated mechanism. 2 In type II AC-expressing mouse RAW 264.7 macrophages, we showed that LPA at 3-50 microM increased cyclic AMP formation in a concentration-dependent manner, the effect being additive with that of forskolin or cholera toxin, and synergistic with that of prostaglandin E1 (PGE1) or isoproterenol. 3 The potentiation effect of LPA was unaffected by the removal of serum or pertussis toxin treatment. 4 Both colchicine and cytochalasin B potentiated the cyclic AMP response to PGE1, the effect being additive to that of LPA. 5 On studying the regulation of type II AC by protein kinase C (PKC), phorbol 12-myristate-13 acetate (PMA) potentiated the PGE1-elicited cyclic AMP response, this effect being non-additive to that of LPA, suggesting that PKC activation was the common mechanism involved in AC potentiation by LPA and PMA. 6 PKC inhibitor Ro 31-8220, but not Go 6976, significantly inhibited the LPA-induced cyclic AMP potentiation. 7 The potentiation effect of LPA was unaffected by long-term treatment with PMA, which resulted in the down-regulation of PKCalpha, betaI, betaII and PKCdelta, but not PKCepsilon, mu, lambda and zeta. 8 By in situ kinase assay, we found a marked increase in atypical PKC activity after LPA treatment. 9 Taken together, we conclude that LPA can elicit a unique signalling cascade in RAW 264.7 macrophages and increase type II AC activity via the activation of atypical PKC.

Adenylate Cyclase Toxin↗
PubMed1999

Involvement of p38 mitogen-activated protein kinase in lipopolysaccharide-induced iNOS and COX-2 expression in J774 macrophages.

Both the nitrite and prostaglandin E2 (PGE2) release caused by lipopolysaccharide (LPS) in J774 macrophages are inhibited by SB 203580, a specific p38 mitogen-activated protein kinase (MAPK) inhibitor, in a concentration-dependent manner. The 50% inhibitory concentration (IC50) for nitrite and PGE2 responses was 1 microm and 0.5 microm, respectively. Inhibition was marked following simultaneous treatment with SB 203580 and LPS, and was much reduced when SB 203580 was added 6 hr after LPS treatment. In parallel, LPS induction of inducible NO synthase (iNOS) and cyclo-oxygenase-2 (COX-2) proteins and their steady-state levels of mRNA were reduced by SB 203580. LPS activation of nuclear factor-kappa B (NF-kappaB), activator protein-1 (AP-1) and p38 MAPK was also inhibited by SB 203580. These results suggest a crucial role of p38 MAPK in regulation of the transcriptional level of endotoxin LPS-induced iNOS and COX-2 protein expression.

Animals↗
PubMed1999

Germ-cell nondisjunction in testes biopsies of men with idiopathic infertility.

Intracytoplasmic sperm injection (ICSI) has been used in combination with testicular sperm extraction to achieve pregnancies in couples with severe male-factor infertility, yet many of the underlying genetic mechanisms remain largely unknown. To investigate nondisjunction in mitotic and meiotic germ cells, we performed three-color FISH to detect numeric chromosome aberrations in testicular tissue samples from infertile men confirmed to have impaired spermatogenesis of unknown cause. FISH was employed to determine the rate of sex-chromosome aneuploidy in germ cells. Nuclei were distinguished as haploid or diploid, respectively. The overall incidence of sex-chromosome aneuploidy in germ cells was found to be significantly higher (P<.00001) in all three abnormal histopathologic patterns (range 39.0%-43.5%) as compared with normal controls (29.1%). The relative ratio of normal to aneuploid nuclei in the diploid cells of patients with impaired spermatogenesis was approximately 1.0, a >300% decrease when compared with the 4.42 ratio detected in patients with normal spermatogenesis. These results provide direct evidence of an increased incidence of sex-chromosome aneuploidy observed in germ cells of men with severely impaired spermatogenesis who might be candidates for ICSI with sperm obtained directly from the testis. The incidence of aneuploidy was significantly greater among the diploid nuclei, which suggests that chromosome instability is a result of altered genetic control during mitotic cell division and proliferation during spermatogenesis.

Biopsy↗
PubMed1999

Spatiotemporal expression of alternatively spliced IGF-I mRNA in the rat costochondral growth plate.

IGF-I acts as a local proliferation and maturation factor for chondrocytes in the growth plate. However, the expression of different alternative IGF-I mRNA classes in the growth plate has not been characterized. Using quantitative reverse transcription PCR, the abundance of each alternative IGF-I mRNA class in resting, proliferative and hypertrophic chondrocytes was measured in rat costochondral growth plates. Class 1Ea mRNA was the most abundant IGF-I transcript overall and was highly expressed in proliferative chondrocytes at 2 and 4 weeks of age; by 6 weeks, the majority of 1Ea mRNA expression had shifted to hypertrophic chondrocytes. Class 1Eb mRNA was the second most abundant transcript and its distribution was uniform across all the cell types at 2 weeks of age. The expression pattern changed with increasing age such that at 6 weeks a gradient existed with hypertrophic chondrocytes expressing higher levels of 1Eb than resting chondrocytes. Class 2Ea mRNA was constitutively expressed at low levels across the growth plate at all ages, while class 2Eb mRNA expression was negligible. The distribution of total IGF-I mRNA also shifted across growth plate cell types as the animals aged from 2 to 6 weeks. These findings suggest that IGF-I class 1 mRNA plays the predominant role in the maturation of the growth plate.

Alternative Splicing↗
PubMed1999

Evaluation of arterial compliance in patients with carotid arterial atherosclerosis.

BACKGROUND: High-resolution peripheral vascular sonography has the capability to determine vessel compliance. A number of factors affect compliance in humans, including age, hypertension and atherosclerosis. However, compliance in patients with coronary artery disease (CAD) combined with carotid artery lesions has not been well studied. The objectives of this study were: 1) to determine whether carotid artery compliance is reduced in patients with CAD and carotid artery lesions, and 2) to determine whether decreased arterial compliance is related to an abnormality in vascular wall structure. METHODS: The study participants included 12 patients with CAD and carotid artery disease (group III), 13 patients with CAD only (group II) and 13 age-matched normal subjects who served as controls (group I). High-resolution peripheral vascular ultrasonography was performed to directly visualize the common carotid artery and to measure its diameter and wall thickness. Carotid artery elastic properties were determined relative to arterial diameter and pressure generated within the heart. RESULTS: Carotid artery walls were thicker in Group II and III patients than in normal subjects (1.49 +/- 0.03 mm, 1.98 +/- 0.04 mm, vs 1.22 +/- 0.03 mm, p < 0.05 and p < 0.01). There were significant differences in wall thickness between subgroups of CAD patients (p < 0.01). Carotid distensibility was lower (21.8 +/- 1.2 x 10(-6).N-1.m2, 14.8 +/- 1.7 x 10(-6).N-1.m2, vs 25.6 +/- 1.5 x 10(-6).N-1.m2; p < 0.05 and p < 0.01) and Young's modulus of elasticity was higher (3.12 +/- 0.43 x 10(5).Nm-2, 4.18 +/- 0.30 x 10(5).Nm-2, vs 2.34 +/- 0.23 x 10(5).Nm-2; p < 0.05 and p < 0.01) in group II and III patients than in normal subjects. These two indices of carotid artery compliance also differed between subgroups of CAD (p < 0.01). Increased wall thickness may occur secondary to changes in the architectural structure of the vessel wall, and these atherosclerotic changes lead to decreased compliance of arteries. CONCLUSION: The mechanical properties of the carotid arteries provide reliable information regarding changes caused by atherosclerosis.

Arteriosclerosis↗
PubMed1998

The G11 gene located in the major histocompatibility complex encodes a novel nuclear serine/threonine protein kinase.

Protein kinases are involved in signal transduction pathways and play fundamental roles in the regulation of cell functions. Here we report that the gene G11 located in the human major histocompatibility complex encodes a novel Ser/Thr protein kinase. The G11 gene products of 41.5 and 30 kDa were expressed in insect cells using the baculovirus system and transiently in the mammalian cell line COS-7. It was found that after immunoprecipitation of the G11 polypeptides from recombinant baculovirus-infected insect cell lysates or transfected COS-7 cell lysates the immunoprecipitates contained a Mn2+-dependent protein kinase activity that phosphorylated alpha-casein at Ser/Thr residues and histone at Ser residues. Furthermore, mutation of the ATP-binding site by converting the invariant lysine in the catalytic domain (amino acid 317) to a proline resulted in the complete ablation of the enzyme activity. This was consistent with the observation that the G11 polypeptide can be covalently modified by the reactive ATP analogue 5'-p-fluorosulfonylbenzoyladenosine in the absence of ATP, and that this modification is prevented in the presence of 1 mM ATP, indicating that the kinase domain of the G11 polypeptide is capable of binding ATP. Immunofluorescence staining of transfected COS-7 cells transiently expressing G11 revealed that this novel Ser/Thr protein kinase is localized predominantly in the nucleus.

Adenosine↗
PubMed1998

Pyrimidinoceptor-mediated potentiation of inducible nitric-oxide synthase induction in J774 macrophages. Role of intracellular calcium.

We have shown that, in murine J774 macrophages, binding of UTP to pyrimidinoceptors stimulates phosphoinositide (PI) breakdown and an increase in [Ca2+]i. In this study, UTP modulation of the expression of inducible nitric-oxide synthase (iNOS) was investigated. Although UTP alone had no effect, stimulation of J774 cells with a combination of UTP (10-300 microM) and LPS (0.1-3 microgram/ml) resulted in a potentiated increase in nitrite levels. In parallel, the amount of iNOS protein induced by LPS was also potentiated by UTP treatment. The UTP potentiating effect was attenuated by U73122, suggesting involvement of the downstream signaling pathways of phosphatidylinositide turnover. The tyrosine kinase inhibitor genistein inhibited both the LPS-induced nitrite response and the UTP potentiation. Conversely, two protein kinase C inhibitors, Ro 31-8220 and Go 6976, and a phosphatidylcholine-specific phospholipase C inhibitor, D609, inhibited LPS-stimulated nitrite induction, but did not affect the potentiating effect of UTP, which was also unaffected by pretreatment with phorbol 12-myristate 13-acetate for 8 h. Furthermore, the UTP-induced potentiation was abolished by BAPTA/AM or KN-93 (a selective inhibitor of Ca2+/calmodulin-dependent protein kinase (CaMK)). Nitrite potentiation and iNOS induction were prominent when UTP was added simultaneously with LPS, with the potentiating effect being lost when UTP was added 3 h after treatment with LPS. Pyrrolidinedithiocarbamate (3-30 microM), an inhibitor of NF-kappaB, caused a concentration-dependent reduction in the nitrite response to LPS and UTP. In electrophoretic mobility shift assays, LPS produced marked activation of NF-kappaB and AP-1, which was potentiated by UTP. LPS-induced degradation of IkappaB-alpha as well as the phosphorylation of IkappaB-alpha were also increased by UTP. Moreover, the UTP-potentiated activation of NF-kappaB and AP-1 and the degradation and phosphorylation of IkappaB-alpha were inhibited by KN-93. Taken together, these data demonstrate that nucleotides, especially UTP, can potentiate the LPS-induced activation of NF-kappaB and AP-1 and of iNOS induction via a CaMK -dependent pathway and suggest that the UTP-dependent up-regulation of iNOS may constitute a novel element in the inflammatory process.

Animals↗
PubMed1998

Effects of a water-soluble extract of Cordyceps sinensis on steroidogenesis and capsular morphology of lipid droplets in cultured rat adrenocortical cells.

Cordyceps sinensis contains a factor that stimulates corticosteroid production in the animal model. However, it is not known whether this drug acts directly on the adrenal glands or indirectly via the hypothalamus-pituitary axis. In the present study, we used primary rat adrenal cell cultures to investigate the pharmacological function of a water-soluble extract of Cordyceps sinensis (CS) and the signaling pathway involved. Radioimmunoassay of corticosterone indicated that the amount of corticosterone produced by adrenal cells is increased in a positively dose-dependent manner by CS, reaching a maximum at 25 microg/ml. This stimulating effect was seen 1 h after CS treatment and was maintained for up to 24 h. Concomitantly, the lipid droplets in these cells became small and fewer in number. Immunostaining with a monoclonal antibody, A2, a specific marker for the lipid droplet capsule, demonstrated that detachment of the capsule from the lipid droplet occurs in response to CS application and that the period required for decapsulation is inversely related to the concentration of CS applied. The mechanism of CS-induced steroidogenesis is apparently different from that for ACTH, since intracellular cAMP levels were not increased in CS-treated cells. However, combined application with calphostin C, a PKC inhibitor, completely blocked the effect of CS on steroidogenesis, suggesting that activation of PKC may be responsible for the CS-induced steroidogenesis.

Adrenal Cortex↗
PubMed1998

Absence of cyclic adenosine 3':5' monophosphate responsive element modulator expression at the spermatocyte arrest stage.

OBJECTIVE: To test the hypotheses that variations in the expression of adenosine 3':5' monophosphate (cAMP) responsive element modulator are found in human seminiferous epithelium in men with impaired testicular function and subsequent infertility and that variations in apoptosis frequency are associated with differential cAMP responsive element modulator expression in male infertility states. DESIGN: Standard immunohistochemical staining using a rabbit polyclonal antibody against the tau isoform of the cAMP responsive element modulator protein was performed on 5-microM sections of Bouin's fixed, paraffin-embedded testicular tissue obtained from azoospermic or severely oligozoospermic men for routine clinical purposes. Histologic diagnosis was confirmed with computerized image analysis of Feulgen-stained sections. SETTING: Tertiary male infertility referral center at a medical school. PATIENT(S): Forty-eight testis biopsies were performed in 38 azoospermic or severely oligozoospermic males. INTERVENTION(S): Rabbit polyclonal cAMP responsive element modulator tau antibody was applied to the paraffin-embedded testis sections. MAIN OUTCOME MEASURE(S): Testis immunoreactivity to polyclonal cAMP responsive element modulator tau antibody and apoptotic indices. RESULT(S): Although cAMP responsive element modulator immunoreactivity was present in the round spermatid stage of meiosis in testis biopsy specimens showing normal spermatogenesis, spermatid maturation arrest, and hypospermatogenesis, there was complete absence of expression in biopsy specimens from patients with Sertoli cell only and spermatocyte maturation arrest states. In addition, significantly increased apoptotic indices were observed in the spermatocyte maturation arrest state in comparison with normal spermatogenesis and Sertoli cell only pattern. CONCLUSION(S): These data suggest that cAMP responsive element modulator may be important for spermatid development and a stage-specific regulator of human spermatogenesis. Absence of cAMP responsive element modulator may be a cause of testicular failure in various types of male infertility.

Adult↗