Development of adrenal cortex zonation Xing, Yewei; Lerario, Antonio M; Rainey, William ...
Endocrinology and metabolism clinics of North America,
06/2015, Letnik:
44, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The human adult adrenal cortex is composed of the zona glomerulosa (zG), zona fasciculata (zF), and zona reticularis (zR), which are responsible for production of mineralocorticoids, glucocorticoids, ...and adrenal androgens, respectively. The final completion of cortical zonation in humans does not occur until puberty with the establishment of the zR and its production of adrenal androgens; a process called adrenarche. The maintenance of the adrenal cortex involves the centripetal displacement and differentiation of peripheral Sonic hedgehog-positive progenitors cells into zG cells that later transition to zF cells and subsequently zR cells.
Microglia are essential for CNS homeostasis and innate neuroimmune function, and play important roles in neurodegeneration and brain aging. Here we present gene expression profiles of purified ...microglia isolated at autopsy from the parietal cortex of 39 human subjects with intact cognition. Overall, genes expressed by human microglia were similar to those in mouse, including established microglial genes CX3CR1, P2RY12 and ITGAM (CD11B). However, a number of immune genes, not identified as part of the mouse microglial signature, were abundantly expressed in human microglia, including TLR, Fcγ and SIGLEC receptors, as well as TAL1 and IFI16, regulators of proliferation and cell cycle. Age-associated changes in human microglia were enriched for genes involved in cell adhesion, axonal guidance, cell surface receptor expression and actin (dis)assembly. Limited overlap was observed in microglial genes regulated during aging between mice and humans, indicating that human and mouse microglia age differently.
Heterozygous variants in the Indian hedgehog gene (IHH) have been reported to cause brachydactyly type A1 and mild hand and feet skeletal anomalies with short stature. Genetic screening in ...individuals with short stature and mild skeletal anomalies has been increasing over recent years, allowing us to broaden the clinical spectrum of skeletal dysplasias.
The objective of this article is to describe the genotype and phenotype of 16 probands with heterozygous variants in IHH.
Targeted next-generation sequencing or Sanger sequencing was performed in patients with short stature and/or brachydactyly for which the genetic cause was unknown.
Fifteen different heterozygous IHH variants were detected, one of which is the first reported complete deletion of IHH. None of the patients showed the classical phenotype of brachydactyly type A1. The most frequently observed clinical characteristics were mild to moderate short stature as well as shortening of the middle phalanx on the fifth finger. The identified IHH variants were demonstrated to cosegregate with the short stature and/or brachydactyly in the 13 probands whose family members were available. However, clinical heterogeneity was observed: Two short-statured probands showed no hand radiological anomalies, whereas another 5 were of normal height but had brachydactyly.
Short stature and/or mild skeletal hand defects can be caused by IHH variants. Defects in this gene should be considered in individuals with these findings, especially when there is an autosomal dominant pattern of inheritance. Although no genotype-phenotype correlation was observed, cosegregation studies should be performed and where possible functional characterization before concluding that a variant is causative.
Abstract
The atrophy and hypofunction of the adrenal cortex following long-term pharmacologic glucocorticoid therapy is a major health problem necessitating chronic glucocorticoid replacement that ...often prolongs the ultimate return of endogenous adrenocortical function. Underlying this functional recovery is anatomic regeneration, the cellular and molecular mechanisms of which are poorly understood. Investigating the lineage contribution of cortical Sonic hedgehog (Shh)+ progenitor cells and the SHH–responsive capsular Gli1+ cells to the regenerating adrenal cortex, we observed a spatially and temporally bimodal contribution of both cell types to adrenocortical regeneration following cessation of glucocorticoid treatment. First, an early repopulation of the cortex is defined by a marked delamination and expansion of capsular Gli1+ cells, recapitulating the establishment of the capsular-cortical homeostatic niche during embryonic development. This rapid repopulation is promptly cleared from the cortical compartment only to be supplanted by repopulating cortical cells derived from the resident long-term-retained zona glomerulosa Shh+ progenitors. Pharmacologic and genetic dissection of SHH signaling further defines an SHH-dependent activation of WNT signaling that supports regeneration of the cortex following long-term glucocorticoid therapy. We define the signaling and lineage relationships that underlie the regeneration process.
This study shows the contribution of capsular and cortical progenitor lineages to adrenal cortex regeneration following dexamethasone-induced atrophy.
Adrenarche refers to the rise of dehydroepiandrosterone sulfate (DHEA-S) associated with the development of a functional adrenal zona reticularis. Clinical features of adrenarche include onset of ...body odor, axillary hair, and pubic hair, which reflect increased androgen action. An early rise in adrenal androgens, or premature adrenarche (PremA), is a risk factor for adverse metabolic profiles in adolescence and adulthood. The bioactive androgens associated with adrenarche and PremA remain poorly understood. The adrenal gland is a potential source of testosterone (T) and the 11-oxygenated derivatives 11β-hydroxytestosterone (11OHT) and 11-ketotestosterone (11KT).
The objective of this study was to characterize the adrenal androgen biome contributing to adrenarche and PremA.
With the use of mass spectrometry, 19 steroids including the 11-oxygenated derivatives of T were measured in sera obtained from girls with PremA (n = 37; 4 to 7 years) and age-matched girls (n = 83; 4 to 10 years).
In reference population girls, dehydroepiandrosterone, DHEA-S, androstenediol-3-sulfate, T, and 11KT all increased at the onset of adrenarche (6 to 8 years) and beyond (9 to 10 years) (P < 0.05 vs younger subjects 4 to 5 years). T, 11OHT, and 11KT were further elevated in PremA vs age-matched girls (P < 0.001). Circulating concentrations of 11KT during adrenarche and PremA exceeded those of T and 11OHT (11KT > T ≥ 11OHT). Androgen receptor activity and nuclear translocation studies demonstrated that 11KT is a potent androgen similar to T.
Our findings suggest that 11KT is the dominant bioactive androgen in children during adrenarche and PremA. Its androgenic capacity suggests that it may be responsible for the phenotypic changes seen in these phenomena.
Abstract
Context
Patients born small for gestational age (SGA) who present with persistent short stature could have an underlying genetic etiology that will account for prenatal and postnatal growth ...impairment. We applied a unique massive parallel sequencing approach in cohort of patients with exclusively nonsyndromic SGA to simultaneously interrogate for clinically substantial genetic variants.
Objective
To perform a genetic investigation of children with isolated short stature born SGA.
Design
Screening by exome (n = 16) or targeted gene panel (n = 39) sequencing.
Setting
Tertiary referral center for growth disorders.
Patients and Methods
We selected 55 patients born SGA with persistent short stature without an identified cause of short stature.
Main Outcome Measures
Frequency of pathogenic findings.
Results
We identified heterozygous pathogenic or likely pathogenic genetic variants in 8 of 55 patients, all in genes already associated with growth disorders. Four of the genes are associated with growth plate development, IHH (n = 2), NPR2 (n = 2), SHOX (n = 1), and ACAN (n = 1), and two are involved in the RAS/MAPK pathway, PTPN11 (n = 1) and NF1 (n = 1). None of these patients had clinical findings that allowed for a clinical diagnosis. Seven patients were SGA only for length and one was SGA for both length and weight.
Conclusion
These genomic approaches identified pathogenic or likely pathogenic genetic variants in 8 of 55 patients (15%). Six of the eight patients carried variants in genes associated with growth plate development, indicating that mild forms of skeletal dysplasia could be a cause of growth disorders in this group of patients.
In the present study, molecular investigation, using massive parallel sequencing, showed effectiveness in diagnosing one in seven patients with prenatal short stature of unknown etiology.
Primary ovarian insufficiency (POI) is a heterogeneous disorder associated with several genes. The majority of cases are still unsolved. Our aim was to identify the molecular diagnosis of a Brazilian ...cohort with POI. Genetic analysis was performed using a customized panel of targeted massively parallel sequencing (TMPS) and the candidate variants were confirmed by Sanger sequencing. Additional copy number variation (CNV) analysis of TMPS samples was performed by CONTRA. Fifty women with POI (29 primary amenorrhea and 21 secondary amenorrhea) of unknown molecular diagnosis were included in this study, which was conducted in a tertiary referral center of clinical endocrinology. A genetic defect was obtained in 70% women with POI using the customized TMPS panel. Twenty-four pathogenic variants and two CNVs were found in 48% of POI women. Of these variants, 16 genes were identified as BMP8B, CPEB1, INSL3, MCM9, GDF9, UBR2, ATM, STAG3, BMP15, BMPR2, DAZL, PRDM1, FSHR, EIF4ENIF1, NOBOX, and GATA4. Moreover, a microdeletion and microduplication in the CPEB1 and SYCE1 genes, respectively, were also identified in two distinct patients. The genetic analysis of eleven patients was classified as variants of uncertain clinical significance whereas this group of patients harbored at least two variants in different genes. Thirteen patients had benign or no rare variants, and therefore the genetic etiology remained unclear. In conclusion, next-generation sequencing (NGS) is a highly effective approach to identify the genetic diagnoses of heterogenous disorders, such as POI. A molecular etiology allowed us to improve the disease knowledge, guide decisions about prevention or treatment, and allow familial counseling avoiding future comorbidities.
•Abnormal PKA activation is present in most of cortisol-producing tumors.•Abnormal membrane depolarization leading to increased cytosolic calcium levels is present in the majority of APAs.•Although ...ACCs are usually sporadic, they can be a manifestation of rare cancer syndromes.•Subgroups of ACCs divided according to genetic and epigenetic markers have different prognosis.•Molecular-targeted therapies are expected to improve clinical responses in advanced ACCs.
Adrenocortical tumors are common neoplasms. Most are benign, nonfunctional and clinically irrelevant. However, adrenocortical carcinoma is a rare disease with a dismal prognosis and no effective treatment apart from surgical resection. The molecular genetics of adrenocortical tumors remain poorly understood. For decades, molecular studies relied on a small number of samples and were directed to candidate-genes. This approach, based on the elucidation of the genetics of rare genetic syndromes in which adrenocortical tumors are a manifestation, has led to the discovery of major dysfunctional molecular pathways in adrenocortical tumors, such as the IGF pathway, the Wnt pathway and TP53. However, with the advent of high-throughput methodologies and the organization of international consortiums to obtain a larger number of samples and high-quality clinical data, this paradigm is rapidly changing. In the last decade, genome-wide expression profile studies, microRNA profiling and methylation profiling allowed the identification of subgroups of tumors with distinct genetic markers, molecular pathways activation patterns and clinical behavior. As a consequence, molecular classification of tumors has proven to be superior to traditional histological and clinical methods in prognosis prediction. In addition, this knowledge has also allowed the proposal of molecular-targeted approaches to provide better treatment options for advanced disease. This review aims to summarize the most relevant data on the rapidly evolving field of genetics of adrenal disorders.
Fanconi Anemia (FA) is a rare and heterogeneous genetic syndrome. It is associated with short stature, bone marrow failure, high predisposition to cancer, microcephaly and congenital malformation. ...Many genes have been associated with FA. Previously, two adult patients with biallelic pathogenic variant in Breast Cancer 1 gene (BRCA1) had been identified in Fanconi Anemia-like condition.
The proband was a 2.5 year-old girl with severe short stature, microcephaly, neurodevelopmental delay, congenital heart disease and dysmorphic features. Her parents were third degree cousins. Routine screening tests for short stature was normal.
We conducted whole exome sequencing (WES) of the proband and used an analysis pipeline to identify rare nonsynonymous genetic variants that cause short stature.
We identified a homozygous loss-of-function BRCA1 mutation (c.2709T > A; p. Cys903*), which promotes the loss of critical domains of the protein. Cytogenetic study with DEB showed an increased chromosomal breakage. We screened heterozygous parents of the index case for cancer and we detected, in her mother, a metastatic adenocarcinoma in an axillar lymph node with probable primary site in the breast.
It is possible to consolidate the FA-like phenotype associated with biallelic loss-of-function BRCA1, characterized by microcephaly, short stature, developmental delay, dysmorphic face features and cancer predisposition. In our case, the WES allowed to establish the genetic cause of short stature in the context of a chromosome instability syndrome. An identification of BRCA1 mutations in our patient allowed precise genetic counseling and also triggered cancer screening for the patient and her family members.
Microglia are the tissue-resident macrophages of the CNS. They originate in the yolk sac, colonize the CNS during embryonic development and form a self-sustaining population with limited turnover. A ...consequence of their relative slow turnover is that microglia can serve as a long-term memory for inflammatory or neurodegenerative events.
Using ATAC-, ChIP- and RNA-sequencing, we characterized the epigenomes and transcriptomes of FACS-purified microglia from mice exposed to different stimuli. A repeated endotoxin challenge (LPS) was used to induce tolerance in microglia, while genotoxic stress (DNA repair deficiency-induced accelerated aging through Ercc1 deficiency) resulted in primed (hypersensitive) microglia.
Whereas the enrichment of permissive epigenetic marks at enhancer regions could explain training (hyper-responsiveness) of primed microglia to an LPS challenge, the tolerized response of microglia seems to be regulated by loss of permissive epigenetic marks. We identify that inflammatory stimuli and accelerated aging as a result of genotoxic stress activate distinct gene networks. These gene networks and associated biological processes are partially overlapping, which is likely driven by specific transcription factor networks, resulting in altered epigenetic signatures and distinct functional (desensitized vs. primed) microglia phenotypes.
This study provides insight into epigenetic profiles and transcription factor networks associated with transcriptional signatures of tolerized and trained microglia in vivo, leading to a better understanding of innate immune memory of microglia.
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