Publications

Central precocious puberty (CPP), defined as the development of secondary sex characteristics prior to age 8 years in girls and 9 years in boys, results from the premature activation of the hypothalamic-pituitary-gonadal axis. Mutations in the imprinted gene MKRN3 have been recently implicated in familial cases of CPP.The objective of the study was to uncover the genetic cause of CPP in a family with two affected siblings.The entire coding region of the paternally expressed MKRN3 gene was sequenced in two siblings, a girl with CPP and her brother with early puberty, their parents, and their grandparents.A novel heterozygous missense variant in the MKRN3 gene (p.C340G) was detected in the two affected siblings, their unaffected father, and the paternal grandmother. As expected, the mutated allele followed an imprinted mode of inheritance within the affected family. In silico analysis predicts the mutation as possibly damaging in all five software packages used. Furthermore, structural alignment of the ab initio native and mutant MKRN3 models predicts that the p.C340G mutation leads to significant structural perturbations in the 3-dimensional structure of the C3HC4 really interesting new gene motif of the protein, further emphasizing the functional implications of the novel MKRN3 alteration.We report a novel MKRN3 mutation (p.C340G) in a girl with CPP and her brother with early puberty. MKRN3 alterations should be suspected in all cases with familial CPP or early puberty, especially if male patients are also involved or the precocious puberty trend does not follow the usually observed mother-to-daughter inheritance.

The major effects of leptin, an adipostatic hormone produced in fat tissue, are exerted through the hypothalamic-pituitary-adrenal axis and the systemic sympathetic/adrenomedullary system at the level of the central nervous system. Here, we examined the direct effects of leptin on the adrenal gland, a peripheral end organ of both the hypothalamic-pituitary-adrenal axis and the sympathetic/adrenomedullary system. As cortical and chromaffin tissues are intermingled in the human adrenal, we employed the novel technique of laser capture microdissection to analyze these systems separately. Functional full-length leptin receptor messenger ribonucleic acid and all human isoforms Ob219.1–3 were demonstrated by RT-PCR in both cortical and medullary tissue. Immunohistochemical staining of leptin receptor protein, however, demonstrated a strong signal only in the adrenal cortex, whereas there was weak positive staining in the medulla. Corticotropin (ACTH)-induced adrenal aldosterone, cortisol, and dehydroepiandrosterone secretion was inhibited by leptin in a concentration-dependent manner, whereas this hormone had no significant effect on catecholamine release by primary cultures of human adrenal chromaffin cells. Leptin itself was not expressed in human adrenal tissue, excluding a local paracrine or autocrine function of this peptide. In conclusion, this is the first report identifying functional leptin receptor in human adrenal tissue and showing a differential action of leptin on human adrenocortical and chromaffin hormone production. This peripheral action of leptin on the adrenal gland provides an additional important link between the human stress response and body weight regulation.

In many chronic inflammatory disorders, glucocorticoid (GC) insensitivity is a challenging clinical problem associated with life-threatening disease progression. The molecular basis of GC insensitivity, however, is unknown. Alternative splicing of the GC receptor (R) pre-messenger RNA generates a second GCR, termed GCR-beta, which does not bind GCs but antagonizes the transactivating activity of the classic GCR, termed GCR-alpha. In the current study, we demonstrate that GC-insensitive asthma is associated with a significantly higher number of GCR-beta-immunoreactive cells in peripheral blood than GC-sensitive asthmatics or normal controls. Furthermore, we show that patients with GC-insensitive asthma have cytokine-induced abnormalities in the DNA binding capability of the GCR. These abnormalities can be reproduced by transfection of cell lines with the GCR-beta gene resulting in significant reduction of their GCR-alpha DNA binding capacity. We conclude that increased expression of GCR-beta is cytokine inducible and may account for GC insensitivity in this common inflammatory condition.

The highly heterogeneous symptomatology and unpredictable progress of COVID‑19 triggered unprecedented intensive biomedical research and a number of clinical research projects. Although the pathophysiology of the disease is being progressively clarified, its complexity remains vast. Moreover, some extremely infrequent cases of thrombotic thrombocytopenia following vaccination against SARS‑CoV‑2 infection have been observed. The present study aimed to map the signaling pathways of thrombocytopenia implicated in COVID‑19, as well as in vaccine‑induced thrombotic thrombocytopenia (VITT). The biomedical literature database, MEDLINE/PubMed, was thoroughly searched using artificial intelligence techniques for the semantic relations among the top 50 similar words (>0.9) implicated in COVID‑19‑mediated human infection or VITT. Additionally, STRING, a database of primary and predicted associations among genes and proteins (collected from diverse resources, such as documented pathway knowledge, high‑throughput experimental studies, cross‑species extrapolated information, automated text mining results, computationally predicted interactions, etc.), was employed, with the confidence threshold set at 0.7. In addition, two interactomes were constructed: i) A network including 119 and 56 nodes relevant to COVID‑19 and thrombocytopenia, respectively; and ii) a second network containing 60 nodes relevant to VITT. Although thrombocytopenia is a dominant morbidity in both entities, three nodes were observed that corresponded to genes (AURKA, CD46 and CD19) expressed only in VITT, whilst ADAM10, CDC20, SHC1 and STXBP2 are silenced in VITT, but are commonly expressed in both COVID‑19 and thrombocytopenia. The calculated average node degree was immense (11.9 in COVID‑19 and 6.43 in VITT), illustrating the complexity of COVID‑19 and VITT pathologies and confirming the importance of cytokines, as well as of pathways activated following hypoxic events. In addition, PYCARD, NLP3 and P2RX7 are key potential therapeutic targets for all three morbid entities, meriting further research. This interactome was based on wild‑type genes, revealing the predisposition of the body to hypoxia‑induced thrombosis, leading to the acute COVID‑19 phenotype, the 'long‑COVID syndrome', and/or VITT. Thus, common nodes appear to be key players in illness prevention, progression and treatment.

No abstract is provided for this article.

Over the past few decades, research at the molecular level has focused on the part of the genome that does not encode protein sequences. Since the discovery of transcriptional evidence from the hitherto considered ‘junk’ DNA, this region of the genome, which is currently termed dark DNA, is constantly gaining interest. The term borrows an analogy from the corresponding eminent fields of dark matter and dark energy in physics and cosmology. In fact, an increasing number of attempts are being made to enhance the current understanding of the non‑coding RNA (ncRNA) transcripts produced by such regions. Although the base‑pair length and gene number appear to be very diverse between species, it appears that the amount of the non‑coding regions of the genome of an organism is a sign of evolutional superiority. ncRNA molecules are able to orchestrate the expression of genetic information in the most complex, rapid and reversible manner, participating in almost every major biological process. A prime example of such a process is the maintenance of homeostasis, the internal physiological balance, despite internal and external stressful stimuli. These molecules have been shown to be excellent regulators of gene expression, with marked spatiotemporal specificity, rendering them ideal tools for regulating stress responses. Herein, an attempt is made to extract and fuse information from a repertoire of studies, which have demonstrated that the expression of a number of these molecules was modified following exposure to acute and chronic stress, as well as in patients with anxiety disorders and their respective animal models. All in all, ncRNAs have the potential to be used either as biomarkers or as therapeutic targets for disorders resulting from the loss of equilibrium, the disruption of homeostasis and the destabilization of the hypothalamic‑pituitary‑adrenal axis.

CRH is a 41 amino acid peptide first isolated from ovine and subsequently from rat and human hypothalami. We have conducted a series of clinical studies with oCRH and hCRH in volunteers and patients with various disorders of hypothalamic-pituitary-adrenal function. In volunteers, it was demonstrated that hCRH administration produced ACTH and cortisol responses which closely mimic naturalistically occurring secretory episodes. This data, as well as the demonstration that pulsatile hCRH can reestablish normal ACTH and cortisol secretion in patients with hypothalamic CRH deficiency, strongly argue that CRH is of physiological relevance to the human pituitary-adrenal axis. However, since the ACTH response to an insulin tolerance test is greater than the maximal ACTH response to CRH, other factors such as vasopressin may be relevant to stress-induced ACTH secretion in man. Following the demonstration that CRH seems to be of physiological relevance to human subjects, a CRH stimulation test was developed based on pharmacokinetic and dose response studies with oCRH and hCRH. Based on these data, which revealed that oCRH functions as a long-acting analogue of hCRH, and the demonstration that hormonal responses to CRH are greatest in the evening, patient groups with abnormalities of the hypothalamic-pituitary-adrenal axis were tested with intravenous oCRH with a dose of 1 micrograms/kg given at 2000 hours. This CRH stimulation test has proved helpful in clarifying the pathophysiology of hypercortisolism in a variety of psychiatric disorders characterized by this endocrine abnormality. Thus, blunted ACTH responses in hypercortisolemic patients with depression, anorexia nervosa, and panic anxiety disorder indicate normality of the pituitary corticotroph in these patient subgroups. These data, along with the finding that a continuous infusion of CRH to normal volunteers, reproduces the pattern and magnitude of hypercortisolism in depression and anorexia nervosa, suggest that the hypercortisolism in these disorders represents a defect at or above the hypothalamus resulting in the hypersecretion of CRH. This hypothesis is particularly intriguing in light of the demonstration that CRH administration to experimental animals produces many of the physiological and behavioral responses classically associated with depression and anorexia nervosa, including hypercortisolism, hypothalamic hypogonadism, and decreases in libido and appetite. The CRH stimulation test has also helped to resolve one of the oldest endocrinological dilemmas, namely whether the hypercortisolism of depression and Cushing's disease share a common or dissimilar pathophysiological basis.(ABSTRACT TRUNCATED AT 400 WORDS)

The syndromes of hereditary IGD and triple A syndrome are potentially life threatening and severely disabling diseases. Clinical awareness of these syndromes is of considerable prognostic and therapeutic importance. The defects in the ACTH receptor causing IGD help illuminate the mechanisms of ligand binding and signal transduction by this receptor. Identification of the molecular defect(s) responsible for IGD cases with a normal ACTH receptor structural gene and for the triple A syndrome remains a challenge, which will hopefully eventually provide further insight into the mechanisms of adrenocortical function. The cloning of the melanocortin receptors has been a giant step towards a better insight into the physiological role of the POMC-derived peptides. It is now becoming apparent that the differential processing of POMC in the brain, the pituitary, and peripheral tissues, yielding a number of different biologically active melanocortin peptides, combined with the distinct tissue distribution and pharmacological profile of the melanocortin receptors will help elucidate the molecular basis of these functions.