HIF3A gene disruption causes abnormal alveoli structure and early neonatal death.

Transcriptional response to changes in oxygen concentration is mainly controlled by hypoxia-inducible transcription factors (HIFs). Besides regulation of hypoxia-responsible gene expression, HIF-3α has recently been shown to be involved in lung development and in the metabolic process of fat tissue. However, the precise mechanism for such properties of HIF-3α is still largely unknown. To this end, we generated HIF3A gene-disrupted mice by means of genome editing technology to explore the pleiotropic role of HIF-3α in development and physiology. We obtained adult mice carrying homozygous HIF3A gene mutations with comparable body weight and height to wild-type mice. However, the number of litters and ratio of homozygous mutation carriers born from the mating between homozygous mutant mice was lower than expected due to sporadic deaths on postnatal day 1. HIF3A gene-disrupted mice exhibited abnormal configuration of the lung such as a reduced number of alveoli and thickened alveolar walls. Transcriptome analysis showed, as well as genes associated with lung development, an upregulation of stearoyl-Coenzyme A desaturase 1, a pivotal enzyme for fatty acid metabolism. Analysis of fatty acid composition in the lung employing gas chromatography indicated an elevation in palmitoleic acid and a reduction in oleic acid, suggesting an imbalance in distribution of fatty acid, a constituent of lung surfactant. Accordingly, administration of glucocorticoid injections during pregnancy resulted in a restoration of normal alveolar counts and a decrease in neonatal mortality. In conclusion, these observations provide novel insights into a pivotal role of HIF-3α in the preservation of critically important structure and function of alveoli beyond the regulation of hypoxia-mediated gene expression.

Unusual manifestations of giant cell arteritis and granulomatosis with polyangiitis.

Giant cell arteritis (GCA) is a type of large vessel vasculitis, and it involves the aorta, large vessels and terminal branches of the external carotid artery, especially the temporal artery. Temporal artery biopsy is a simple tool for the diagnosis of vasculitis, however, the histopathological findings do not always differentiate between the small-vessel vasculitis and GCA. We report the case of 72-year-old male who initially had a clinical diagnosis of GCA, then in the course of treatment, diagnostic histopathological approach revealed the necrotizing vasculitis with bronchocentric granulomatosis in the inflammatory nodule of the lung. The manifestations of patients with systemic vasculitis represent the disorders of multiple organ systems thus are diverse and may vary through the course of the disease. Presentation of unexpected features such as insufficient response to antibiotics, sinusitis, runny nose, discomfort of frontal region or pachymeningitis which anticipates re-evaluation of systemic vasculitis that may lead us to an appropriate diagnosis and the treatment.