The hormone corticotropin (ACTH) is employed as therapy for diverse neurological disorders, but the mechanisms for its efficacy remain unknown. ACTH promotes the release of adrenal steroids (glucocorticoids), and most ACTH effects on the central nervous system (CNS) have been attributed to activation of glucocorticoid receptors. However, in several human disorders, ACTH has therapeutic actions that differ qualitatively or quantitatively from those of steroids. This study tested the hypothesis that ACTH directly influences limbic neurons via the recently characterized melanocortin receptors and focused on the effects of ACTH on the expression of corticotropinreleasing hormone (CRH), a neuropeptide involved in neuroimmune functions and in certain developmental seizures. The results demonstrated that ACTH potently reduced CRH expression in amygdala neurons. This down-regulation was not abolished by experimental elimination of steroids or by blocking their receptors and was reproduced by a centrally administered ACTH fragment that does not promote steroid release. Importantly, selective blocking of melanocortin receptors prevented ACTH-induced down-regulation of CRH expression. Taken together, these data indicate that ACTH activates central melanocortin receptors to modulate CRH gene expression in amygdala, supporting the notion that direct, steroid-independent actions of ACTH may account for some of its established clinical effects on the CNS.The hormone corticotropin (ACTH) has been used extensively to treat neurological disorders. In some auto-immune disorders (eg, opsoclonus-myoclonus) and in certain developmental seizure disorders (eg, infantile spasms), ACTH possesses increased efficacy or a different spectrum of effects compared to adrenal steroids. [1][2][3][4] However, the mechanisms for these singular actions of ACTH on the central nervous system (CNS) have remained unresolved. 1,5 Native ACTH is synthesized in the pituitary and functions to stimulate the adrenal cortex to release steroids into the blood stream as part of the neuroendocrine stress response. Neurons containing ACTH have been localized to the CNS, particularly the hypothalamus, and ACTHimmunoreactive cell bodies or fibers have also been described in amygdala, cerebral cortex, brainstem, and cerebellum. 6,7 In contrast to pituitary ACTH, the functions of CNS ACTH have not been well-defined. Evidence from both human and animal studies has suggested that CNS ACTH may function as a neurotransmitter/neuromodulator. The goal of the current studies was to examine whether ACTH directly influenced CRH gene expression in the immature rat amygdala. Because steroids also regulate CRH expression in this region, this study focused on discerning steroid-independent effects, testing the hypothesis that ACTH suppresses CRH expression in amygdaloid central nucleus (ACe) directly, via activation of central melanocortin receptors. Materials and Methods Materials Experimental DesignSeveral experiments were carried out to test the hypothesis that ACTH al...
The 2:1 ratio of female to male EPTB cases coincides with the unusual epidemiologic pattern seen in smear-positive pulmonary TB in Afghanistan. As the first epidemiological report of EPTB from Afghanistan, this study illustrates the varied presentations of EPTB that should be known by healthcare workers throughout the country.
Soil salinity is a major factor affecting rice growth and productivity worldwide especially at seedling stage. Many genes for salt tolerance have been identified and applied to rice breeding, but the actual mechanism of salt tolerance remains unclear. In this study, seedlings of 664 cultivated rice varieties from the 3000 Rice Genome Project (3K-RG) were cultivated by hydroponic culture with 0.9% salt solution for trait identification. A genome-wide association study (GWAS) of salt tolerance was performed using different models of analysis. Twenty-one QTLs were identified and two candidate genes named OsSTL1 (Oryza sativa salt tolerance level 1) and OsSTL2 (Oryza sativa salt tolerance level 2) were confirmed using sequence analysis. Haplotype and sequence analysis revealed that gene OsSTL1 was a homolog of salt tolerance gene SRP1 (Stress associated RNA-binding protein 1) in Arabidopsis. The hap1 of OsSTL1 was identified as the superior haplotype and a non-synonymous SNP was most likely to be the functional site. We also determined that the level of salt tolerance was improved by combining haplotypes of different genes. Our study provides a foundation for molecular breeding and functional analysis of salt tolerance in rice seedlings.
Hepatitis delta virus (HDV) is a defective RNA virus that depends on the presence of hepatitis B virus (HBV) for the creation of new virions and propagation of the infection to hepatocytes. Chronic infection with HDV is usually associated with a worsening of HBV infection, leading more frequently to cirrhosis, increased risk of liver decompensation and hepatocellular carcinoma (HCC) occurrence. In spite of a progressive declining prevalence of both acute and chronic HDV infection observed over several years, mainly due to increased global health policies and mass vaccination against HBV, several European countries have more recently observed stable HDV prevalence mainly due to migrants from non-European countries. Persistent HDV replication has been widely demonstrated as associated with cirrhosis development and, as a consequence, development of liver decompensation and occurrence of HCC. Several treatment options have been attempted with poor results in terms of HDV eradication and improvement of long-term prognosis. A global effort is deemed urgent to enhance the models already existing as well as to learn more about HDV infection and correlated tumourigenesis mechanisms.
Summary Yield in rice is determined mainly by panicle architecture. Using map‐based cloning, we identified an R2R3 MYB transcription factor REGULATOR OF GRAIN NUMBER1 (RGN1) affecting grain number and panicle architecture. Mutation of RGN1 caused an absence of lateral grains on secondary branches. We demonstrated that RGN1 controls lateral grain formation by regulation of LONELY GUY (LOG) expression, thus controlling grain number and shaping panicle architecture. A novel favourable allele, RGN1C, derived from the Or‐I group in wild rice affected panicle architecture by means longer panicles. Identification of RGN1 provides a theoretical basis for understanding the molecular mechanism of lateral grain formation in rice; RGN1 will be an important gene resource for molecular breeding for higher yield.
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