Jiqiang Zhang

Distribution and differences of estrogen receptor beta immunoreactivity in the brain of adult male and female rats.

Studies have shown that estrogen plays important roles in regulating neural structure and function in the brain, but the mechanism remains unclear. The actions of estrogen were thought to be mediated by a single estrogen receptor until the identification of another estrogen receptor, namely estrogen receptor-beta (ER-beta). Here we report a comprehensive study of the localization of ER-beta immunoreactivity and differences in the brains of adult male and female rats on the basis of a nickel ammonium sulfate-enhanced immunocytochemical method using a polyclonal antiserum sc-8974. The results of these studies revealed: (1) ER-beta immunoactive material was mainly localized in the neuronal nucleus, but it was also detectable in the cytoplasm and neuronal processes; (2) in both male and female rats, high levels of ER-beta immunopositive signals were detected in the anterior olfactory nucleus, cerebral cortex, Purkinje cells, vertical limb of the diagonal band, red nucleus, locus ceruleus, and motor trigeminal nucleus. Moderate levels were found in the medial septum, lateral amygdaloid nucleus, substantia nigra, and central gray. Weak signals were localized in other subregions of the hypothalamus and amygdaloid complex; (3) there was an obvious difference of ER-beta immunoreactivity between male and female rats, and its intracellular distribution also showed a sex difference. The above results provide the first detailed evidence that ER-beta protein is widely distributed in both male and female rat brains, but that distinctive sex differences also exist. Estrogen may exert its function in different brain regions in a gender-specific manner.

Neutrophil extracellular trap formation is associated with autophagy-related signalling in ANCA-associated vasculitis.

Increasing evidence indicates that aberrant neutrophil extracellular trap (NET) formation could contribute to the pathogenesis of anti‐neutrophil cytoplasmic antibody (ANCA)‐associated vasculitis (AAV). Recent research has provided evidence that a novel type of ANCA autoantibody, anti‐lysosomal membrane protein‐2 (LAMP‐2) antibody, may have a pathogenic role in AAV. We have shown previously that anti‐LAMP‐2 antibody‐stimulated NET formation contains autoantigens and anti‐microbial peptides. The current study sought to determine whether LAMP‐2, as a novel antigen of ANCA, was present on NETs in AAV patients, the influence of the anti‐LAMP‐2 antibody on the neutrophil apoptosis rate and the role of autophagy in anti‐LAMP‐2 antibody‐induced NET formation. NET formation was assessed using immunofluorescence microscopy, scanning electron microscopy or live cell imaging. The neutrophil apoptosis rate was analysed using fluorescence activated cell sorting (FACS). Autophagy was detected using LC3B accumulation and transmission electron microscopy. The results showed that enhanced NET formation, which contains LAMP‐2, was observed in kidney biopsies and neutrophils from AAV patients. The apoptosis rate decreased significantly in human neutrophils stimulated with anti‐LAMP‐2 antibody, and this effect was attenuated by the inhibitors of autophagy 3‐methyladenine (3MA) and 2‐morpholin‐4‐yl‐8‐phenylchromen‐4‐one (LY294002). The anti‐LAMP‐2 antibody‐stimulated NET formation was unaffected by benzyloxycarbonyl‐Val‐ Ala‐Asp (OMe)‐fluoromethylketone (zVAD‐fmk) and necrostatin‐1 (Nec‐1), which are inhibitors of apoptosis and necrosis, respectively, but was inhibited by 3MA and LY294002. Moreover, the proportion of LC3BI that was converted to LC3BII increased significantly (P = 0·0057), and massive vacuolizations that exhibited characteristics typical of autophagy were detected in neutrophils stimulated with anti‐LAMP‐2 antibody. Our results provide further evidence that autophagy is involved in ANCA‐induced NET formation in human neutrophils.

Localization and sex-difference of steroid receptor coactivator-1 immunoreactivities in the brain of adult female and male mice

Females and males are different in brain and behaviors. These differences are mediated by steroids and their nuclear receptors which require coactivators to regulate the transcription of target genes. Studies have shown that these coactivators are critical for modulating steroid hormone action in the brain. Steroid receptor coactivator-1 has been implied in the regulation of reproduction, stress, motor learning, and limited studies have reported the sex-specific difference of SRC-1 mRNA or protein expression in specific brain regions, but the expression and differences of SRC-1 immunoreactivities in adult female and male brain remain unclear. In this study we reported that in both sexes, high levels of SRC-1 immunoreactivities were detected in olfactory bulb, cerebral cortex, hippocampus, Purkinje cells, some limited diencephalon and brainstem nuclei. The immunopositive materials were predominantly detected in cell nucleus, but in some regions they were also detected in the processes or fiber-like structures. In most of the brain regions studied, males possessed significantly higher levels of SRC-1 immunoreactivities than that of females. Higher levels of SRC-1 were detected in some nuclei related to learning and memory, motor regulation and reproduction indicated its potential roles in neurodegeneration and sex-dependent behavior and structure; the region- and sex-specific localization of SRC-1 immunoreactivities in agreement with that of some steroid receptors, indicating this coactivator play important roles in these hormone-reactive regions and cell groups related to reproduction, learning and memory, integration of motor and sense.

Alterations of steroid receptor coactivator-1 (SRC-1) immunoreactivities in specific brain regions of young and middle-aged female Sprague–Dawley rats

Previous studies have shown that steroid receptor coactivator-1 (SRC-1) is involved in the regulation of Purkinje cell development and motor learning, neural stem cell differentiation and reproductive-related plasticity. It is widely distributed in the adult brain, but the aging-related changes in the brain remain unclear. In this study age-related alterations of SRC-1 expression in female brain were examined. The results showed that striking age-related decreases of SRC-1 were noticed in those regions related to central regulation of motor (substantia nigra, pontine nuclei, lateral reticular nucleus and Purkinje cells, etc.), learning and memory (olfactory bulb, hippocampus, Purkinje cells, etc.), and neural stem cell (olfactory, dentate gyrus, cerebral cortex, etc.). Surprisingly, although SRC-1 immunopositive materials were predominantly detected in the cell nuclei, they were also detected in the extra-nuclear components predominantly in these motor-regulation sub-regions. The above results showing age-related decrease of SRC-1 in specific motor, learning and memory nuclei suggested its potential roles in neurodegenerative disorders, which may be one of the underlying mechanisms of the vulnerability of the aged brain.

Apolipoprotein E gene polymorphism and Alzheimer's disease in Chinese population: a meta-analysis

The relationship between Apolipoprotein E (ApoE) genotype and the risk of Alzheimers disease (AD) is relatively well established in Caucasians, but less established in other ethnicities. To examine the association between ApoE polymorphism and the onset of AD in Chinese population, we searched the commonly used electronic databases between January 2000 and November 2013 for relevant studies. Total 20 studies, including 1576 cases and 1741 controls, were retrieved. The results showed statistically significant positive association between risk factor ε4 allele carriers and AD in Chinese population (OR = 3.93, 95% CI = 3.37–4.58, P < 0.00001). Genotype ApoE ε4/ε4 and ε4/ε3 have statistically significant association with AD as well (ε4/ε4: OR = 11.76, 95% CI = 6.38–21.47, P < 0.00001; ε4/ε3: OR = 3.08, 95% CI = 2.57–3.69, P < 0.00001). Furthermore, the frequency of the ApoE ε3 is lower in AD than that in the health controls, and the difference of ε3 allele is also statistically significant (OR = 0.42, 95% CI = 0.37–0.47, P < 0.00001). No significant heterogeneity was observed among all studies. This meta-analysis suggests that the subject with at least one ApoE ε4 allele has higher risk suffering from AD than controls in Chinese population. The results also provide a support for the protection effect of ApoE ε3 allele in developing AD.

MicroRNAs in the diagnosis and prognosis of breast cancer and their therapeutic potential (Review)

MicroRNAs (miRNAs) are non-coding single-stranded RNAs in eukaryotes and are involved in the regulation of the post-transcriptional expression of specific genes. Studies have demonstrated that miRNAs play important roles in regulating diverse physiological events such as cell proliferation, differentiation and embryo development. In recent decades, considerable attention has been given to the relationship between miRNA and the pathology of cancers, particularly breast cancer. A large number of miRNAs have been shown to be involved in the pathophysiology of breast cancer. Studies have revealed that some miRNAs might regulate the oncogenesis and growth of breast cancer by acting on breast tumor-initiating cells or other downstream targets. Studies have also demonstrated that some miRNAs act as suppressors of metastasis or promoters of breast cancer. Additionally, certain miRNAs are involved in cancer tissue angiogenesis (one of the most important mechanisms of tumor growth and metastasis). Clinical evidence indicates that some miRNAs can be used as diagnostic and prognostic biomarkers for breast cancer due to their significantly increased or decreased expression in cancer tissue. Moreover, certain miRNAs may have therapeutic potential for targeting ER-α/HER, breast tumor-initiating cells and metastasis as well as multidrug resistance. In this review, we discuss the relationship between miRNAs and the pathogenesis of breast cancer as well as the progress of current research on the miRNA-specific diagnosis, prognosis and treatment of breast cancer.

Sex differences and synchronous development of steroid receptor coactivator-1 and synaptic proteins in the hippocampus of postnatal female and male C57BL/6 mice

The structure and function including synaptic plasticity of the hippocampus are deeply affected by steroids in a sex-dependant manner, these processes are believed to be mediated by steroid receptors though their coactivators. Our previous studies have reported the developmental profiles of steroid receptor coactivator-1 (SRC-1) and PSD-95 in the hippocampus of postnatal female rats and the sex-differences of SRC-1 immunoreactivities in the brain of adult mice. However, whether there are any sex differences about postnatal development of SRC-1 and synaptic proteins in the hippocampus remain unclear. In this study, we investigated the postnatal profile of SRC-1 and key synaptic protein synaptophysin (SYN), PSD-95 and GluR1 in the hippocampus of female and male mice using immunohistochemistry and Western blot. The results showed that in the female hippocampus, the highest levels of SRC-1 were detected at P14, SYN and GluR1 at P30 and PSD-95 at P60; while in the males, the highest levels of SRC-1, SYN and GluR1 were detected at P30, and PSD-95 at P60. Female hippocampus tended to have higher levels of SRC-1, SYN and GluR1 before P30 and PSD-95 before P14; while male hippocampus have higher levels of PSD-95 at P14, P60 and GluR1 at P0. Correlation analysis showed the profiles of SRC-1 were highly correlated with each synaptic protein. The above results showed that in the hippocampus, except some minor sex differences detected at some time-point examined, females and males shared similar postnatal developmental profile and SRC-1 may be deeply involved in the regulation of hippocampal synaptogenesis.

Brain REST/NRSF Is Not Only a Silent Repressor but Also an Active Protector

During neurogenesis, specific transcription factors are needed to repress neuronal genes in nonneuronal cells to ensure precise development. Repressor element-1 binding transcription factor (REST), or neuron-restrictive silencer factor (NRSF), has been shown to be an important regulator for the establishment of neuronal specificity. It restricts the expression of neuronal genes by binding to the neuron-restrictive silencer element (NRSE/RE1) domain in neuron-specific genes. REST/NRSF regulates many target genes in stem cells, nonneural cells, and neurons, which are involved in neuronal differentiation, axonal growth, vesicular transport, and release as well as ionic conductance. However, it is also regulated by some cytokines/regulators such as epigenetic factors (microRNAs) and even its truncated isoform. REST/NRSF is widely detected in brain regions and has been shown to be highly expressed in nonneuronal cells, but current findings also reveal that, at least in the human brain, it is also highly expressed in neurons and increases with ageing. However, its loss in expression and cytoplasmic translocation seems to play a pivotal role in several human dementias. Additionally, REST/NRSF knockdown leads to malformations in nerve and nonneural tissues and embryonic lethality. Altered REST/NRSF expression has been not only related to deficient brain functions such as neurodegenerative diseases, mental disorders, brain tumors, and neurobehavioral disorders but also highly correlated to brain injuries such as alcoholism and stroke. Encouragingly, several compounds such as valproic acid and X5050 that target REST/NRSF have been shown to be clinically effective at rescuing seizures or Niemann-Pick type C disease. Surprisingly, studies have also shown that REST/NRSF can function as an activator to induce neuronal differentiation. These findings strongly indicate that REST/NRSF is not only a classical repressor to maintain normal neurogenesis, but it is also a fine fundamental protector against neurodegeneration and other disorders and may be a novel potent therapeutic target for neural disturbances.

Expression of Steroid Receptor Coactivator-1 Was Regulated by Postnatal Development but Not Ovariectomy in the Hippocampus of Rats

Female steroids such as estrogens and progestins, through their nuclear receptors, play important roles in regulation of the structure and function of the hippocampus. Steroid receptor coactivator-1 (SRC-1) has been detected in embryonic and/or adult hippocampus of rodents, and SRC-1 null mice showed significantly longer escape latency in the Morris maze test, indicating a role of this coactivator in the regulation of hippocampus function. Whether this is regulated by development and circulating ovary hormones remains unclear. In this study, postnatal development and ovariectomy for regulation of hippocampal SRC-1 in female rats were investigated by Western blot and immunohistochemistry. The results showed that SRC-1-immunopositive materials were predominantly detected in the CA1 pyramidal cell layer and dentate gyrus granular cell layer. Very low levels of SRC-1 were detected at postnatal day 0, but they increased with development. The highest levels of SRC-1 were detected at postnatal day 14, then they decreased to adult levels from postnatal day 30; significantly lower levels of SRC-1 were detected in the middle-aged (18-month-old) hippocampus when compared with that of the adult. Western blot and immunohistochemistry demonstrated that hippocampal SRC-1 expression was unchanged after ovariectomy, no significant differences were noticed from day 3 to 8 weeks postsurgery when compared with sham animals. The above results showed that hippocampal SRC-1 is regulated by postnatal development but not ovariectomy, and that the exact role of SRC-1 in the estradiol regulation of hippocampus needs further investigation.

Overexpression and Gender-specific Differences of SRC-3 (SRC-3/AIB1) Immunoreactivity in Human Non-Small Cell Lung Cancer: An In Vivo Study:

Steroid receptor coactivator-3 (SRC-3) has been reported to be overexpressed in the development and progression of many tumor types. SRC-3 has been detected in several lung cancer cell lines, but its expression and clinical significance in non-small cell lung cancer (NSCLC) remain unclear. In this study, 48 NSCLC tissues were collected and tissue microarrays were performed. The expression of SRC-3 was examined using nickel-intensified IHC. The results showed that of these 48 cases, 18 (37.5%) exhibited high levels of SRC-3 immunoreactivity, 23 (47.9%) exhibited moderate levels of SRC-3 immunoreactivity, and 7 (14.6%) were negative; thus, the total frequency of SRC-3 overexpression was 85.4% (41/48). This SRC-3 overexpression frequency was similar to the overexpression frequency observed for squamous cell carcinoma and adenocarcinoma (82.1% vs 90%) and for metastasis and non-metastasis patients (84.6% vs 85.7%). Data analysis demonstrated a significantly higher overexpression frequency in male patients compared with that in female patients (88.6% vs 76.9%). However, female patients tended to have higher expression levels of SRC-3, as measured by immunoreactivity, than male patients. These results demonstrate a high frequency of SRC-3 overexpression in NSCLC with a gender difference, suggesting that there is a specific role for SRC-3 in the pathogenesis of NSCLC. (J Histochem Cytochem 58:1121–1127, 2010)