GATA augments GNRH-mediated increases in Adcyap1 gene expression in pituitary gonadotrope cells

A Rare Case of Precocious Puberty in a Child with a Novel GATA-4 Gene Mutation: Implications for Disorders of Sex Development (DSD) and Review of the Literature

BACKGROUND

Disorders/Differences of sex development (DSD) are often due to disruptions of the genetic programs that regulate gonad development. The GATA-4 gene, located on chromosome 8p23.1, encodes GATA-binding protein 4 (GATA-4), a transcription factor that is essential for cardiac and gonadal development and sexual differentiation.

CASE DESCRIPTION

A child with a history of micropenis and cryptorchidism. At 8 years of age, he came under our observation for an increase in sexual pubic hair (pubarche). The laboratory parameters and the GnRH test suggested a central precocious puberty (CPP). Treatment with GnRH analogs was started, and we decided to perform genetic tests for DSD. The NGS genetic investigation showed a novel and heterozygous variant in the GATA-4 gene.

DISCUSSION

In the literature, 26 cases with 46,XY DSD due to the GATA4 gene were reported.

CONCLUSION

The novel variant in the GATA-4 gene of our patient was not previously associated with DSD. This is the first case of a DSD due to a GATA-4 mutation that develops precocious puberty. Precocious puberty could be associated with DSD and considered a prelude to hypogonadism in some cases.

Positive allosteric regulation of PAC1-R up-regulates PAC1-R and its specific ligand PACAP

PAC1-R is a recognized preferential receptor for the neuropeptide of pituitary adenylate cyclase-activating polypeptide (PACAP), which mediates neuroprotective and nerve regenerative activities of PACAP. In this study, we found that in both PAC1R-CHO cells with high expression of PAC1R-eGFP and retinal ganglion cells (RGC-5) with the natural expression of PAC1-R, oligo-peptide PACAP(28-38) and the positively charged arginine-rich penetrating peptide TAT, as positive allosteric modulators of PAC1-R, significantly trigger the nuclear translocation of PAC1-R. The chromatin immunoprecipitation (ChIP)-PCR results show that the nuclear translocated PAC1-R binds with the promoter regions of PAC1-R and its specific ligand PACAP. The up-regulated promoter activities of PAC1-R and PACAP induced by PACAP(28-38) or TAT are positively correlative with the increase of the expression levels of PAC1-R and PACAP. Moreover, the nuclear translocation of PAC1-R induced by PACAP(28-38) or TAT is significantly inhibited by the mutation of PAC1-R on Cys25 and the palmitoylation inhibitor 2-bromopalmitate. Meanwhile, the increase in both PAC1-R and PACAP levels and the neuroprotective activities of PACAP(28-38) and TAT in MPP-induced cell model of Parkinson ' s disease are synchronously inhibited by 2-bromopalmitate, which are positively correlated with the nuclear translocation of PAC1-R induced by PACAP(28-38) or TAT. Bioinformatics analysis and motif enrichment analysis following ChIP-sequencing show that the transcription factors including SP1, Zic2, GATA1, REST and YY1 may be recruited by nuclear PAC1-R and involved in regulating the promoter activities of PAC1-R and PACAP. ChIP-sequencing and related bioinformatics analysis show that the downstream target genes regulated by the nuclear PAC1-R are mostly involved in the process of cellular stress and related to neuroprotection, neuronal genesis and development.

Cloning and expression analysis of GATA1 gene in Carassius auratus red var

BACKGROUND

GATA1 is a key transcription factor in the GATA family, and promotes the differentiation and maturation of red blood cell, which is essential for normal hematopoiesis.

RESULTS

Our results showed that the cDNA sequence of GATA1 was 2730 bp long encoding 443 amino acids. qRT-PCR analysis demonstrated that GATA1 had the highest expression in testis (T), followed by pituitary (P) and spleen (S). GATA1 gene expression in C. auratus red var. embryo from the neuroblast stage (N) to the embryo hatching (H) changes continuously; and the gene expression levels of nonylphenol (NP)-treated and those of control embryos were significantly different. Moreover, Methylation levels of GATA1 gene in NP-treated embryos were higher than those in control embryos, indicating that NP affected GATA1 methylation.

CONCLUSIONS

Our study provides cues for further studying the roles of GATA1 gene in fish development, and suggested a potential molecular mechanism by which NP leads to abnormal development of fish embryos.

Precocious or early puberty in patients with combined pituitary hormone deficiency due to POU1F1 gene mutation: case report and review of possible mechanisms

Central precocious puberty (CPP) or early puberty (EP) is a rare entity in combined pituitary hormone deficiency (CPHD), the latter caused by mutations in pituitary transcription factor genes. The early onset of puberty in two patients with CPHD with POU1F1 gene mutation was evaluated. A 3-month-old boy was diagnosed with central hypothyroidism, and L-thyroxine was commenced. He was referred for the evaluation of short stature at 20 months of age. Anthropometric evaluation revealed severe short stature (- 6.1 SDS), and growth hormone (GH) and prolactin deficiencies were diagnosed. Homozygous POU1F1 gene mutation (c.731T>G, p. I244S) was also detected. Testicular enlargement and high luteinizing hormone (LH) levels were observed at 7 years and 9 months of age while he was on GH and L-thyroxine treatment. Due to rapid progression of puberty, gonadotropin-releasing hormone analogue (GnRHa) was initiated at 11.3 years of age. This patient recently turned 19.2 years old, and his final height was - 2.3 SDS. The second patient, a 6-month-old boy, was also referred for growth retardation. His height was - 2.7 SDS, and GH and thyroid-stimulating hormone (TSH) deficiencies were diagnosed. He also had homozygous (c.10C>T, p.Q4*) POU1F1 gene mutation. Onset of puberty was relatively early, at 10 years, with advanced bone age. He was on GnRHa treatment between 11.5 and 12.5 years of age. Recent evaluation of the patient was at 13.6 years of age, and he is still on levothyroxine and GH treatment. The relationship between the POU1F1 genotype and CPP or EP has not as yet been firmly established in humans. Animal studies have revealed that the Pou1f1 gene has a major effect on regulation of GnRH receptor function and the Gata2 gene. It has also been demonstrated that this gene controls gonadotrope evolution and prevents excess gonadotropin levels. Further studies are, however, needed to elucidate the relation between POU1F1 function and CPP.

An embryonic atrazine exposure results in reproductive dysfunction in adult zebrafish and morphological alterations in their offspring

The herbicide atrazine, a suspected endocrine disrupting chemical (EDC), frequently contaminates potable water supplies. Studies suggest alterations in the neuroendocrine system along the hypothalamus-pituitary-gonadal axis; however, most studies address either developmental, pubertal, or adulthood exposures, with few investigations regarding a developmental origins hypothesis. In this study, zebrafish were exposed to 0, 0.3, 3, or 30 parts per billion (ppb) atrazine through embryogenesis and then allowed to mature with no additional chemical exposure. Reproductive function, histopathology, hormone levels, offspring morphology, and the ovarian transcriptome were assessed. Embryonic atrazine exposure resulted in a significant increase in progesterone levels in the 3 and 30 ppb groups. A significant decrease in spawning and a significant increase in follicular atresia in the 30 ppb group were observed. In offspring, a decrease in the head length to body ratio in the 30 ppb group, along with a significant increase in head width to body ratio in the 0.3 and 3 ppb groups occurred. Transcriptomic alterations involved genes associated with endocrine system development and function, tissue development, and behavior. This study provides evidence to support atrazine as an EDC causing reproductive dysfunction and molecular alterations in adults exposed only during embryogenesis and morphological alterations in their offspring.

PACAP modulates GnRH signaling in gonadotropes

Hypothalamic gonadotropin-releasing hormone is known to be critical for normal gonadotropin biosynthesis and secretion by the gonadotrope cells of the anterior pituitary gland. Additional regulation is provided by gonadal steroid feedback as well as by intrapituitary factors, such as activin and follistatin. Less well-appreciated is the role of pituitary adenylate-cyclase activating polypeptide (PACAP) as both a hypothalamic-pituitary releasing factor as well as an autocrine-paracrine factor within the pituitary. PACAP regulates gonadotropin expression alone and through modulation of GnRH responsiveness achieved by increases in GnRH receptor expression and interactions at the level of intracellular signaling pathways. In addition to direct effects on the gonadotrope, PACAP stimulates follistatin secretion by the folliculostellate cells and thereby contributes to differential expression of the gonadotropin subunits. Conversely, GnRH augments the ability of PACAP to regulate gonadotrope function by increasing pituitary PACAP and PACAP receptor expression. This review will summarize the current understanding of the mechanisms by which PACAP modulates gonadotrope function, with a focus on interactions with GnRH.