Characterization of Two Novel Variants of the Steroidogenic Acute Regulatory Protein Identified in a Girl with Classic Lipoid Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) consists of several autosomal recessive disorders that inhibit steroid biosynthesis. We describe a case report diagnosed with adrenal insufficiency due to low adrenal steroids and adrenocorticotropic hormone excess due to lack of cortisol negative feedback signaling to the pituary gland. Genetic work up revealed two missense variants, p.Thr204Arg and p.Leu260Arg in the STAR gene, inherited by both parents (non-consanguineous). The StAR protein supports CYP11A1 enzyme to cleave the side chain of cholesterol and synthesize pregnenolone which is metabolized to all steroid hormones. We used bioinformatics to predict the impact of the variants on StAR activity and then we performed functional tests to characterize the two novel variants. In a cell system we tested the ability of variants to support cholesterol conversion to pregnenolone and measured their mRNA and protein expression. For both variants, we observed loss of StAR function, reduced protein expression and categorized them as pathogenic variants according to guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. These results fit the phenotype of the girl during diagnosis. This study characterizes two novel variants and expands the list of missense variants that cause CAH

A Novel Single Domain Antibody Targeting FliC Flagellin of Salmonella enterica for Effective Inhibition of Host Cell Invasion

The enteric pathogen, Salmonella enterica is a major cause of human gastroenteritis globally and with increasing bacterial resistance to antibiotics, alternative solutions are urgently needed. Single domain antibodies (sdAbs), the smallest antibody fragments that retain antigen binding specificity and affinity, are derived from variable heavy-chain only fragments (VHH) of camelid heavy-chain-only immunoglobulins. SdAbs typically contain a single disulfide bond simplifying recombinant protein production in microbial systems. These factors make sdAbs ideally suited for the development of effective anti-bacterial therapeutics. To this end, we generated an anti-Salmonella VHH library from which we screened for high affinity sdAbs. We present a novel sdAb (Abi-Se07) that targets the Salmonella virulence factor, FliC, required for bacterial motility and invasion of host cells. We demonstrate that Abi-Se07 bound FliC with a KD of 16.2 ± 0.1 nM. In addition, Abi-Se07 exhibited cross-serovar binding to whole cells of S. enterica serovar Typhimurium, Heidelberg, and Hadar. Abi-Se07 significantly inhibited bacterial motility and significantly reduced S. enterica colonization in a more native environment of chicken jejunum epithelium. Taken together, we have identified a novel anti-Salmonella sdAb and discuss future efforts toward therapeutic development.Fil: Huen, Jennifer. AbCelex Technologies Inc.; Canadá. University of Toronto; CanadáFil: Yan, Zhun. AbCelex Technologies Inc.; CanadáFil: Iwashkiw, Jeremy. AbCelex Technologies Inc.; CanadáFil: Dubey, Shraddha. AbCelex Technologies Inc.; CanadáFil: Gimenez, Maria C.. University of Toronto; CanadáFil: Ortiz, María Eugenia. University of Toronto; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Patel, Saumil V.. AbCelex Technologies Inc.; CanadáFil: Jones, Michael D.. AbCelex Technologies Inc.; CanadáFil: Riazi, Ali. AbCelex Technologies Inc.; CanadáFil: Terebiznik, Mauricio. University of Toronto; CanadáFil: Babaei, Saeid. AbCelex Technologies Inc.; CanadáFil: Shahinas, Dea. AbCelex Technologies Inc.; Canad

Secondary open-angle pigmentary glaucoma resulting from a single-piece hydrophobic intraocular lens in the sulcus

The case report of a 68-year-old man with a single-piece hydrophobic intraocular lens (IOL) implanted in the sulcus with posterior capsular rent in the right eye inducing secondary open-angle pigmentary glaucoma without individual hereditary steroid susceptibility. The clinical and diagnostic evaluations of the patient were thoroughly and specifically carried out. The unilateral pseudophakic open-angle pigmentary glaucoma developed in the long course in the context of rubbing of the haptics and optic of a hydrophobic IOL implanted in the sulcus, against the posterior surface of the iris, resulting in pigment dispersion, trabecular inflammation, and aqueous outflow obstruction. Although the clinical findings of our case were very similar to that of pigmentary glaucoma, the distinction between the two conditions was still quite easy, considering that pigmentary glaucoma is a bilateral disorder predominantly affecting young myopic men with Krukenberg's spindle and increased incidence of steroid responsiveness. It has been clearly distinguished from steroid-induced glaucoma based on the pigmented trabecular meshwork

Characterization of Two Novel Variants of the Steroidogenic Acute Regulatory Protein Identified in a Girl with Classic Lipoid Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) consists of several autosomal recessive disorders that inhibit steroid biosynthesis. We describe a case report diagnosed with adrenal insufficiency due to low adrenal steroids and adrenocorticotropic hormone excess due to lack of cortisol negative feedback signaling to the pituary gland. Genetic work up revealed two missense variants, p.Thr204Arg and p.Leu260Arg in the STAR gene, inherited by both parents (non-consanguineous). The StAR protein supports CYP11A1 enzyme to cleave the side chain of cholesterol and synthesize pregnenolone which is metabolized to all steroid hormones. We used bioinformatics to predict the impact of the variants on StAR activity and then we performed functional tests to characterize the two novel variants. In a cell system we tested the ability of variants to support cholesterol conversion to pregnenolone and measured their mRNA and protein expression. For both variants, we observed loss of StAR function, reduced protein expression and categorized them as pathogenic variants according to guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. These results fit the phenotype of the girl during diagnosis. This study characterizes two novel variants and expands the list of missense variants that cause CAH

Neurons are the Primary Target Cell for the Brain-Tropic Intracellular Parasite <i>Toxoplasma gondii</i>

<div><p><i>Toxoplasma gondii</i>, a common brain-tropic parasite, is capable of infecting most nucleated cells, including astrocytes and neurons, <i>in vitro</i>. Yet, <i>in vivo</i>, <i>Toxoplasma</i> is primarily found in neurons. <i>In vitro</i> data showing that interferon-γ-stimulated astrocytes, but not neurons, clear intracellular parasites suggest that neurons alone are persistently infected <i>in vivo</i> because they lack the ability to clear intracellular parasites. Here we test this theory by using a novel <i>Toxoplasma</i>-mouse model capable of marking and tracking host cells that directly interact with parasites, even if the interaction is transient. Remarkably, we find that <i>Toxoplasma</i> shows a strong predilection for interacting with neurons throughout CNS infection. This predilection remains in the setting of IFN-γ depletion; infection with parasites resistant to the major mechanism by which murine astrocytes clear parasites; or when directly injecting parasites into the brain. These findings, in combination with prior work, strongly suggest that neurons are not incidentally infected, but rather they are <i>Toxoplasma</i>’s primary <i>in vivo</i> target.</p></div