Monica M. França

Growth hormone pharmacogenetics: the interactive effect of a microsatellite in the IGF1 promoter region with the GHR-exon 3 and-202 A/C IGFBP3 variants on treatment outcomes of children with severe GH deficiency

Insulin-like growth factor type 1 (IGF1) is a mediator of growth hormone (GH) action, and therefore, IGF1 is a candidate gene for recombinant human GH (rhGH) pharmacogenetics. Lower serum IGF1 levels were found in adults homozygous for 19 cytosine–adenosine (CA) repeats in the IGF1 promoter. The aim of this study was to evaluate the influence of (CA)n IGF1 polymorphism, alone or in combination with GH receptor (GHR)-exon 3 and −202 A/C insulin-like growth factor binding protein-3 (IGFBP3) polymorphisms, on the growth response to rhGH therapy in GH-deficient (GHD) patients. Eighty-four severe GHD patients were genotyped for (CA)n IGF1, −202 A/C IGFBP3 and GHR-exon 3 polymorphisms. Multiple linear regressions were performed to estimate the effect of each genotype, after adjustment for other influential factors. We assessed the influence of genotypes on the first year growth velocity (1st y GV) (n=84) and adult height standard deviation score (SDS) adjusted for target-height SDS (AH-TH SDS) after rhGH therapy (n=37). Homozygosity for the IGF1 19CA repeat allele was negatively correlated with 1st y GV (P=0.03) and AH-TH SDS (P=0.002) in multiple linear regression analysis. In conjunction with clinical factors, IGF1 and IGFBP3 genotypes explain 29% of the 1st y GV variability, whereas IGF1 and GHR polymorphisms explain 59% of final height-target-height SDS variability. We conclude that homozygosity for IGF1 (CA)19 allele is associated with less favorable short- and long-term growth outcomes after rhGH treatment in patients with severe GHD. Furthermore, this polymorphism exhibits a non-additive interaction with −202 A/C IGFBP3 genotype on the 1st y GV and with GHR-exon 3 genotype on adult height.

High Frequency of MKRN3 Mutations in Male Central Precocious Puberty Previously Classified as Idiopathic

Background/Aims: Recently, loss-of-function mutations in the MKRN3 gene have been implicated in the etiology of familial central precocious puberty (CPP) in both sexes. We aimed to analyze the frequency of MKRN3 mutations in boys with CPP and to compare the clinical and hormonal features of boys with and without MKRN3 mutations. Methods: This was a retrospective review of clinical, hormonal and genetic features of 20 male patients with idiopathic CPP evaluated at an academic medical center. The entire coding regions of MKRN3, KISS1 and KISS1R genes were sequenced. Results: We studied 20 boys from 17 families with CPP. All of them had normal brain magnetic resonance imaging. Eight boys from 5 families harbored four distinct heterozygous MKRN3 mutations predicted to be deleterious for protein function, p.Ala162Glyfs*14, p.Arg213Glyfs*73, p.Arg328Cys and p.Arg365Ser. One boy carried a previously described KISS1-activating mutation (p.Pro74Ser). The frequency of MKRN3 mutations among these boys with idiopathic CPP was significantly higher than previously reported female data (40 vs. 6.4%, respectively, p < 0.001). Boys with MKRN3 mutations had typical clinical and hormonal features of CPP. Notably, they had later pubertal onset than boys without MKRN3 abnormalities (median age 8.2 vs. 7.0 years, respectively, p = 0.033). Conclusion: We demonstrated a high frequency of MKRN3 mutations in boys with CPP, previously classified as idiopathic, suggesting the importance of genetic analysis in this group. The boys with CPP due to MKRN3 mutations had classical features of CPP, but with puberty initiation at a borderline age.

POD-1 binding to the E-box sequence inhibits SF-1 and StAR expression in human adrenocortical tumor cells

Pod-1/Tcf21 is expressed at epithelial-mesenchymal interaction sites during development of many organs. Different approaches have demonstrated that Pod-1 transcriptionally inhibits Sf-1/NR5A1 during gonadal development. Disruption of Sf-1 can lead to disorders of adrenal development, while increased dosage of SF-1 has been related to increased adrenal cell proliferation and tumorigenesis. In this study, we analyzed whether POD-1 overexpression inhibits the endogenous Sf-1 expression in human and mouse adrenocortical tumor cells. Cells were transiently transfected with luciferase reporter gene under the control of Sf-1 promoter and with an expression vector encoding Pod-1. Pod-1 construct inhibited the transcription of the Sf1/Luc reporter gene in a dose-dependent manner in mouse Y-1 adrenocortical carcinoma (ACC) cells, and inhibited endogenous SF-1 expression in the human H295R and ACC-T36 adrenocortical carcinoma cells. These results were validated by chromatin immunoprecipitation assay with POD-1-transfected H295R cells using primers specific to E-box sequence in SF-1 promoter region, indicating that POD-1 binds to the SF-1 E-box promoter. Moreover, POD-1 over-expression resulted in a decrease in expression of the SF-1 target gene, StAR (Steroidogenic Acute Regulatory Protein). Lastly, while the induced expression of POD-1 did not affect the cell viability of H295R/POD-1 or ACC-T36/POD-1 cells, the most significantly enriched KEGG pathways for genes negatively correlated to POD-1/TCF21 in 33 human ACCs were those associated with cell cycle genes.

Identification of the first homozygous 1-bp deletion in GDF9 gene leading to primary ovarian insufficiency by using targeted massively parallel sequencing

Targeted massively parallel sequencing (TMPS) has been used in genetic diagnosis for Mendelian disorders. In the past few years, the TMPS has identified new and already described genes associated with primary ovarian insufficiency (POI) phenotype. Here, we performed a targeted gene sequencing to find a genetic diagnosis in idiopathic cases of Brazilian POI cohort. A custom SureSelectXT DNA target enrichment panel was designed and the sequencing was performed on Illumina NextSeq sequencer. We identified 1 homozygous 1‐bp deletion variant (c.783delC) in the GDF9 gene in 1 patient with POI. The variant was confirmed and segregated using Sanger sequencing. The c.783delC GDF9 variant changed an amino acid creating a premature termination codon (p.Ser262Hisfs*2). This variant was not present in all public databases (ExAC/gnomAD, NHLBI/EVS and 1000Genomes). Moreover, it was absent in 400 alleles from fertile Brazilian women screened by Sanger sequencing. The patients mother and her unaffected sister carried the c.783delC variant in a heterozygous state, as expected for an autosomal recessive inheritance. Here, the TMPS identified the first homozygous 1‐bp deletion variant in GDF9. This finding reveals a novel inheritance pattern of pathogenic variant in GDF9 associated with POI, thus improving the genetic diagnosis of this disorder.

A Novel Homozygous Missense FSHR Variant Associated with Hypergonadotropic Hypogonadism in Two Siblings from a Brazilian Family

Hypergonadotropic hypogonadism (HH) is defined by increased gonadotropin levels in men and women. Primary ovarian failure (POF) is a form of female infertility characterized by amenorrhea, hypoestrogenism, and elevated gonadotropin levels in women under the age of 40 years. Although several genes have been associated with POF, its causative genes remain to be identified. Here, we used whole-exome sequencing (WES) to study a consanguineous family with a 46,XX girl and a 46,XY man affected by HH. All exons of both siblings and their parents were captured and massively sequenced by WES, and the candidate variant was confirmed by Sanger sequencing. A novel c.1298C>A;p.Ala433Asp missense variant of the follicle-stimulating hormone receptor (FSHR) gene was found in both affected siblings in a homozygous state and in their parents in a heterozygous state. This FSHR variant is not present in available databases (1000 Genomes and NHLBI/EVS) and Brazilian exome controls. Moreover, it is highly conserved and predicted as deleterious in all prediction sites analyzed. In conclusion, the novel homozygous FSHR variant observed in 2 siblings with HH can expand the spectrum of FSHR mutations in humans.

POD-1/TCF21 Reduces SHP Expression, Affecting LRH-1 Regulation and Cell Cycle Balance in Adrenocortical and Hepatocarcinoma Tumor Cells.

POD-1/TCF21 may play a crucial role in adrenal and gonadal homeostasis and represses Sf-1/SF-1 expression in adrenocortical tumor cells. SF-1 and LRH-1 are members of the Fzt-F1 subfamily of nuclear receptors. LRH-1 is involved in several biological processes, and both LRH-1 and its repressor SHP are involved in many types of cancer. In order to assess whether POD-1 can regulate LRH-1 via the same mechanism that regulates SF-1, we analyzed the endogenous mRNA levels of POD-1, SHP, and LRH-1 in hepatocarcinoma and adrenocortical tumor cells using qRT-PCR. Hereafter, these tumor cells were transiently transfected with pCMVMycPod-1, and the effect of POD-1 overexpression on E-box elements in the LRH-1 and SHP promoter region were analyzed by ChIP assay. Also, Cyclin E1 protein expression was analyzed to detect cell cycle progression. We found that POD-1 overexpression significantly decreased SHP/SHP mRNA and protein levels through POD-1 binding to the E-box sequence in the SHP promoter. Decreased SHP expression affected LRH-1 regulation and increased Cyclin E1. These findings show that POD-1/TCF21 regulates SF-1 and LRH-1 by distinct mechanisms, contributing to the understanding of POD-1 involvement and its mechanisms of action in adrenal and liver tumorigenesis, which could lead to the discovery of relevant biomarkers.

Central Precocious Puberty Caused by a Heterozygous Deletion in the MKRN3 Promoter Region

Context: Loss-of-function mutations in the coding region of MKRN3, a maternally imprinted gene at chromosome 15q11.2, are a common cause of familial central precocious puberty (CPP). Whether MKRN3 alterations in regulatory regions can cause CPP has not been explored to date. We aimed to investigate potential pathogenic variants in the promoter region of MKRN3 in patients with idiopathic CPP. Patients/Methods: A cohort of 110 patients with idiopathic CPP was studied. Family history of precocious sexual development was present in 25%. Mutations in the coding region of MKRN3 were excluded in all patients. Genomic DNA was extracted from peripheral blood leukocytes, and 1,100 nucleotides (nt) of the 5′-regulatory region of MKRN3 were amplified and sequenced. Luciferase assays were performed in GT1–7 cells transiently transfected with plasmids containing mutated and wild-type MKRN3 promoter. Results: We identified a rare heterozygous 4-nt deletion (c.-150_-147delTCAG; –38 to –41 nt upstream to the transcription start site) in the proximal promoter region of MKRN3 in a girl with CPP. In silico analysis predicted that this deletion would lead to the loss of a binding site for a downstream responsive element antagonist modulator (DREAM), a potential transcription factor for MKRN3 and GNRH1 expression. Luciferase assays demonstrated a significant reduction of MKRN3 promoter activity in transfected cells with a c.-150_- 147delTCAG construct plasmid in both homozygous and heterozygous states when compared with cells transfected with the corresponding wild-type MKRN3 promoter region. Conclusion: A rare genetic alteration in the regulatory region of MKRN3 causes CPP.

A novel homozygous 1-bp deletion in the NOBOX gene in two Brazilian sisters with primary ovarian failure

PurposePrimary ovarian failure (POF) is characterized by amenorrhea, hypoestrogenism, and elevated gonadotropin levels in women leading to infertility under the age of 40 years. POF is a heterogeneous disease with different causes, and several genes have been associated with the POF phenotype. Thus, Whole-exome sequencing (WES) was performed in a consanguineous family with two sisters affected by POF.MethodsAll exons of both sisters were massively sequenced by WES, and the segregation was confirmed by Sanger sequencing.ResultsThe novel homozygous c.1489delT variant in the NOBOX gene was identified in the two sisters with POF. Their parents were heterozygous carriers of this variant and, therefore, consistent with an autosomal recessive mode of inheritance. The c.1489delT NOBOX variant has not been previously reported in any public available databases (1000Genomes, 6500ESP/EVS, ExAC, and gnomAD). Furthermore, this variant was neither present in 387 Brazilian exomes control individuals nor in 200 fertile Brazilian women screened by Sanger sequencing.ConclusionWe report the first familial case of a novel homozygous NOBOX variant with an autosomal recessive mode of inheritance, thus allowing for a genetic diagnosis of primary ovarian failure.

New evidences on the regulation of SF-1 expression by POD1/TCF21 in adrenocortical tumor cells

OBJECTIVES: Transcription Factor 21 represses steroidogenic factor 1, a nuclear receptor required for gonadal development, sex determination and the regulation of adrenogonadal steroidogenesis. The aim of this study was to investigate whether silencing or overexpression of the gene Transcription Factor 21 could modulate the gene and protein expression of steroidogenic factor 1 in adrenocortical tumors. METHODS: We analyzed the gene expression of steroidogenic factor 1 using qPCR after silencing endogenous Transcription Factor 21 in pediatric adrenal adenoma-T7 cells through small interfering RNA. In addition, using overexpression of Transcription Factor 21 in human adrenocortical carcinoma cells, we analyzed the protein expression of steroidogenic factor 1 using Western blotting. RESULTS: Transcription Factor 21 knockdown increased the mRNA expression of steroidogenic factor 1 by 5.97-fold in pediatric adrenal adenoma-T7 cells. Additionally, Transcription Factor 21 overexpression inhibited the protein expression of steroidogenic factor 1 by 0.41-fold and 0.64-fold in two different adult adrenocortical carcinoma cell cultures, H295R and T36, respectively. CONCLUSIONS: Transcription Factor 21 is downregulated in adrenocortical carcinoma cells. Taken together, these findings support the hypothesis that Transcription Factor 21 is a regulator of steroidogenic factor 1 and is a tumor suppressor gene in pediatric and adult adrenocortical tumors.

Nonspecific binding of a frequently used vitamin D receptor (VDR) antibody: important implications for vitamin D research in human health

Amid the ongoing debate surrounding optimal vitamin D status for bone and mineral homeostasis, the investigation of extraskeletal effects of vitamin D on several aspects of human health has burgeoned in recent years [1–4]. Indeed, a variety of potentially beneficial actions of vitamin D have been proposed, including in areas of major public health concerns such as cancer and cardiovascular disease [5–7]. Besides the cumulative epidemiological evidence linking serum 25-hydroxyvitamin levels to extraskeletal outcomes, biological plausibility of these pleiotropic effects has derived from the identification of the vitamin D receptor (VDR) in numerous cells and tissues beyond those directly involved in bone metabolism [8, 9]. The human VDR is a 427-amino-acid nuclear receptor that regulates transcription of hundreds of target genes in response to 1,25-hydroxyvitamin D (1,25D) by directly binding to DNA response elements throughout the genome [8, 10]. Selective expression of nuclear receptors in their target tissues is a hallmark of this superfamily of transcription factors [11]; therefore, proposed pleiotropic actions of 1,25D are soundly endorsed by the identification of the VDR in these sites. Evidence of VDR expression in extraskeletal systems can be found at the mRNA level and, more consequentially, at protein level, most commonly through immunorecognition by antibodies. It becomes important, therefore, to scrutinize the specificity of VDR recognition by commonly used antibodies in order to correctly appreciate expression data. The careful analyses of specificity of commercially available VDR antibodies have been duly undertaken at the DeLuca’s lab in a series of papers from 2010 onwards [12–14]; comparative analyses of antibody specificity were mainly performed in non-human models. Their results collectively show a superiority of the D-6 antibody. Nevertheless, the less specific C-20 antibody has continued to be used subsequently in several studies in humans. A search on Google Scholar performed in April 2016 returned more than 150 citations using this antibody, a third of those since 2013. VDR defects lead to hereditary vitamin D-resistant rickets (HVDRR), an autosomal recessive disorder characterized by early-onset hypocalcemic rickets [8]. We have reported the long-term follow-up of a male patient with HVDRR caused by a severe VDR defect (p.Arg30*) [15]. This homozygous DNA mutation introduces a stop codon in the beginning of the reading frame, leading to a severely truncated protein lacking functional domains, and resulting in natural VDR ablation in his cells (Fig. 1a). Here, we describe the analysis of VDR expression in human fibroblasts bearing wild type or p.Arg30* mutant VDR using the C-20 and D-6 VDR antibodies, with strikingly contrasting results.