Long Term Pharmacological Perturbation of Autophagy in Mice: Are HCQ Injections a Relevant Choice?

Abstract

Macroautophagy (hereafter referred to as autophagy) is an evolutionarily conserved catabolic process whose loss-of-function has been linked to a growing list of pathologies. Knockout mouse models of key autophagy genes have been instrumental in the demonstration of the critical functions of autophagy, but they display early lethality, neurotoxicity and unwanted autophagy-independent phenotypes, limiting their applications for in vivo studies. To avoid problems encountered with autophagy-null transgenic mice, we investigated the possibility of disturbing autophagy pharmacologically in the long term. Hydroxychloroquine (HCQ) ip injections were done in juvenile and adult C57bl/6j mice, at range doses adapted from the human malaria prophylactic treatment. The impact on autophagy was assessed by western-blotting, and juvenile neurodevelopment and adult behaviours were evaluated for four months. Quite surprisingly, our results showed that HCQ treatment in conditions used in this study neither impacted autophagy in the long term in several tissues and organs nor altered neurodevelopment, adult behaviour and motor capabilities. Therefore, we recommend for future long-term in vivo studies of autophagy, to use genetic mouse models allowing conditional inhibition of selected Atg genes in appropriate lineage cells instead of HCQ treatment, until it could be successfully revisited using higher HCQ doses and/or frequencies with acceptable toxicity.

Brief Report: Hydroxychloroquine does not induce hemolytic anemia or organ damage in a “humanized” G6PD A- mouse model

“…Wild-type (WT) littermate male or G6PD A- male mice (n = 10/group) at 13-weeks were administered 60 mg/kg HCQ by intraperitoneal injection every 24 hrs for 5 days. This dose is higher than the 50 mg/kg dose equivalent to a human dose for anti-malarial prophylaxis [ 8 ]. Murine tail vein blood (70 μL) was sampled from each mouse on experimental day 1 prior to receiving drug.…”

Autophagy as an emerging target for COVID-19: lessons from an old friend, chloroquine

“…For in vitro experiments, a dose range of 10-100 μM has been used for the inhibition of autophagy in various cells [61]. For in vivo experiments in mice, a dose of 30-70 mg/kg body weight (not more than 3 doses/week) has been used [62]. However, in the treatment of systemic lupus erythematosus and other autoimmune diseases, and depending on the severity of the disease, patients have received 200-400 mg of CQ/ HCQ either by a single daily dose or two divided doses [63].…”

Organoid technology and lung injury mouse models evaluating effects of hydroxychloroquine on lung epithelial regeneration

“…Serum HCQ levels were reported to range from 0-7.9 μM in patients according to a weightbased dosing of 6.5 mg/kg [45,46]. Further, the 50% maximal effective concentration (EC50) of HCQ was found to range from 4.06-12.96 μM in VeroE6 cells [6].…”

“…In this study, we adopted a 3-D lung organoid platform and lung epithelial injury repair mouse models to assess the effects of HCQ on lung epithelial regeneration. Serum HCQ levels were reported to range from 0–7.9 µ M in patients according to a weight-based dosing of 6.5 mg/kg [ 45 , 46 ]. Further, the 50% maximal effective concentration (EC50) of HCQ was found to range from 4.06–12.96 µ M in VeroE6 cells [ 6 ].…”