Spergen-1 Might Be an Adhesive Molecule Associated with Mitochondria in the Middle Piece of Spermatozoa

AbstractSpergen-1, a recently identified molecule specifically expressed in haploid spermatids in testis, is a small protein of 154 amino acids with a mitochondria-targeting signal at the N terminus. To examine the localization of spergen-1 protein in germ cells, we performed immunocytochemistry with the anti-spergen-1 antibody on frozen sections of rat testis and purified spermatozoa. Immunolabeling for spergen-1 was detected in mitochondria of elongating spermatids and of the middle pieces of matured spermatozoa. Immunoelectron microscopy revealed that spergen-1 was localized to the surface of mitochondria in the middle piece of spermatozoa. To investigate the properties of spergen-1, COS-7 cells were transfected with vectors encoding various spergen-1 mutants. The transfection experiments showed that spergen-1 expressed in the cells tended to agglutinate mitochondria and assemble them into aggregations and that the C-terminal region of spergen-1 as well as the N-terminal mitochondrial targeting signal was requisite for induction of mitochondrial aggregation. These results suggest that spergen-1, a mitochondria-associated molecule in spermatozoa, has a property to induce mitochondrial aggregation at least in cultured cells. We hypothesize that spergen-1 might function as an adhesive molecule to assemble mitochondria into the mitochondrial sheath around the outer dense fibers during spermiogenesis

Daño Cerebral Hipóxico-Isquémico en Ratas de 7 Días de Edad: Alteraciones Neurológicas Tempranas y Lesiones Permanentes

OBJECTIVES: To study the changes after hypoxia-ischemia (HI), and to observe both, the vulnerability of the different regions of the brain to HI and the heat shock protein-72 kDa (HSP72) induction and its efects on the neuronal cell. MATERIAL AND METHODS: 7-days-old rats were exposed to left carotid artery ligation followed by 2 h of HI and then they were sacrificed at different time points. Brains extracted at 1-72 h were immunohistochemically study using the HSP-72 and the microtubule associated protein-2 (MAP2) stainings. Brains extracted at 1-4 weeks underwent histopathological study. RESULTS: Loss of MAP2 immunostaining was detected since the 1st hour post-insult, being highest at 24 h. MAP2 reappeared at 72 h in almost all the brain regions of the ligated hemisphere, except the hippocampal CA3 region. At 1-2 weeks post HI, we observed atrophic and cystic lesions. 15-20% of rats did not show any anatomical lesion up to 4 weeks post HI. The HSP72 synthesis was early in the dentate gyrus of the hippocampus, but a delayed induction was observed in the CA3 region; this region showed an increased vulnerability to HI. CONCLUSIONS: Absence of anatomical lesion was observed in 15-20% of rats exposed to HI. Atrophic or cystic lesions are observed since 1-2 weeks after the insult, despite an apparent immunohistochemical recovery at 72 h.OBJETIVOS: Observar las diferencias de vulnerabilidad de las diferentes regiones cerebrales frente a la hipoxia isquemia (HI), y la inducción de la síntesis de marcadores de injuria neuronal y su efecto posterior en la neurona. MATERIALES Y MÉTODOS: Se ligó la arteria carótida izquierda a ratas de 7 días de edad, seguido de 2 h de hipoxia, sacrificándolas a diferentes intervalos de tiempo. Se realizó un estudio inmunohistoquímico con la proteína del golpe del calor de 72 kDa (HSP72) y la proteína asociada al microtúbulo tipo 2 (MAP2) durante las primeras 72 h. RESULTADOS: La pérdida de inmunotinción del MAP2 se observó desde la 1 h, siendo máxima a las 24 h, pero a las 72 h se observó una reaparición en la mayoría de regiones del hemisferio izquierdo, excepto la región CA3 del hipocampo. Entre 1 y 2 semanas después se observó lesiones de tipo atrófico y cístico. 15-20% de ratas no sufrió daño anatómico hasta las 4 semanas. Hubo síntesis temprana de HSP72 en el giro dentado del hipocampo, mientras que en la región CA3 su inducción fue tardía, observándose aquí mayor vulnerabilidad a la HI. CONCLUSIONES: En 15 a 20% de ratas sometidas a HI no se observa daño anatómico hasta las 4 semanas. La lesión atrófica o cística se consolida entre 1 y 2 semanas después del insulto, a pesar de una aparente recuperación inmunohistoquímica a las 72 h

Daño Cerebral Hipóxico-Isquémico en Ratas de 7 Días de Edad: Alteraciones Neurológicas Tempranas y Lesiones Permanentes

OBJECTIVES: To study the changes after hypoxia-ischemia (HI), and to observe both, the vulnerability of the different regions of the brain to HI and the heat shock protein-72 kDa (HSP72) induction and its efects on the neuronal cell. MATERIAL AND METHODS: 7-days-old rats were exposed to left carotid artery ligation followed by 2 h of HI and then they were sacrificed at different time points. Brains extracted at 1-72 h were immunohistochemically study using the HSP-72 and the microtubule associated protein-2 (MAP2) stainings. Brains extracted at 1-4 weeks underwent histopathological study. RESULTS: Loss of MAP2 immunostaining was detected since the 1st hour post-insult, being highest at 24 h. MAP2 reappeared at 72 h in almost all the brain regions of the ligated hemisphere, except the hippocampal CA3 region. At 1-2 weeks post HI, we observed atrophic and cystic lesions. 15-20% of rats did not show any anatomical lesion up to 4 weeks post HI. The HSP72 synthesis was early in the dentate gyrus of the hippocampus, but a delayed induction was observed in the CA3 region; this region showed an increased vulnerability to HI. CONCLUSIONS: Absence of anatomical lesion was observed in 15-20% of rats exposed to HI. Atrophic or cystic lesions are observed since 1-2 weeks after the insult, despite an apparent immunohistochemical recovery at 72 h.OBJETIVOS: Observar las diferencias de vulnerabilidad de las diferentes regiones cerebrales frente a la hipoxia isquemia (HI), y la inducción de la síntesis de marcadores de injuria neuronal y su efecto posterior en la neurona. MATERIALES Y MÉTODOS: Se ligó la arteria carótida izquierda a ratas de 7 días de edad, seguido de 2 h de hipoxia, sacrificándolas a diferentes intervalos de tiempo. Se realizó un estudio inmunohistoquímico con la proteína del golpe del calor de 72 kDa (HSP72) y la proteína asociada al microtúbulo tipo 2 (MAP2) durante las primeras 72 h. RESULTADOS: La pérdida de inmunotinción del MAP2 se observó desde la 1 h, siendo máxima a las 24 h, pero a las 72 h se observó una reaparición en la mayoría de regiones del hemisferio izquierdo, excepto la región CA3 del hipocampo. Entre 1 y 2 semanas después se observó lesiones de tipo atrófico y cístico. 15-20% de ratas no sufrió daño anatómico hasta las 4 semanas. Hubo síntesis temprana de HSP72 en el giro dentado del hipocampo, mientras que en la región CA3 su inducción fue tardía, observándose aquí mayor vulnerabilidad a la HI. CONCLUSIONES: En 15 a 20% de ratas sometidas a HI no se observa daño anatómico hasta las 4 semanas. La lesión atrófica o cística se consolida entre 1 y 2 semanas después del insulto, a pesar de una aparente recuperación inmunohistoquímica a las 72 h

Interaction between basigin and monocarboxylate transporter 2 in the mouse testes and spermatozoa

Basigin is a member of the immunoglobulin superfamily and plays various important roles in biological events including spermatogenesis. To examine the basigin molecular variants during spermatogenesis and sperm maturation in the mouse, immunoprecipitated basigin samples from testis and epididymal spermatozoa were analyzed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). The results demonstrated that basigin molecules from the testis and spermatozoa were separable into two major bands and that the differences in the molecular sizes were possibly because of an endoproteolytic cleavage. Since basigin is known to be a chaperone for the monocarboxylate transporter 1 (MCT1), the localization of basigin, MCT1 and MCT2 was examined during postnatal testicular development. Immunohistochemical studies showed different expression patterns of MCT1 and MCT2. MCT1 was localized on the surface of spermatogonia, spermatocytes, and spermatids. In contrast, MCT2 appeared on the principal piece of spermatozoa in the testis, where basigin was also observed. In mature epididymal spermatozoa, MCT2 was located on the midpiece, where basigin co-localized with MCT2 but not with MCT1. Furthermore, MCT2 was immunoprecipitated with basigin in mouse testes and sperm. These results suggest that basigin has a functional role as a binding partner with MCT2 in testicular and epididymal spermatozoa