Carotid body Type I cells engage flavoprotein and Pin1 for oxygen sensing.

Carotid body Type I cells engage flavoprotein and Pin1 for oxygen sensing. Am J Physiol Cell Physiol. 2020 Jan 22;: Authors: Bernardini A, Wolf A, Brockmeier U, Riffkin H, Metzen E, Acker-Palmer A, Fandrey J, Acker H Abstract Carotid body (CB) Type I cells sense the blood pO2 and generate a nervous signal for stimulating ventilation and circulation when blood oxygen levels decline. Three oxygen sensing enzyme complexes may be used for this purpose: 1) mitochondrial electron transport chain metabolism, 2) heme oxygenase 2 (HO-2) generating CO and/or 3) an NAD(P)H oxidase (NOX). We hypothesize that intracellular redox changes are the link between the sensor and nervous signals. To test this hypothesis Type I cell autofluorescence of flavoproteins (Fp) and NAD(P)H within the mouse CB ex vivo was recorded as Fp/(Fp+NAD(P)H) redox ratio. CB Type I cell redox ratio transiently declined with the onset of hypoxia. Upon reoxygenation, CB Type I cells showed a significantly increased redox ratio. As a control organ, the non-oxygen sensing sympathetic superior cervical ganglion (SCG) showed a continuously reduced redox ratio upon hypoxia. CN-, DPI or ROS influenced chemoreceptor discharge (CND) with subsequent loss of O2 sensitivity and inhibited hypoxic Fp reduction only in the CB but not in SCG Fp, indicating a specific role of Fp in the oxygen sensing process. Hypoxia induced changes in CB Type I cell redox ratio affected peptidyl prolyl iso...
Source: Am J Physiol Cell Ph... - Category: Cytology Authors: Tags: Am J Physiol Cell Physiol Source Type: research