Cyclophilin D Is Involved in the Regulation of Autophagy and Affects the Lifespan of P. anserina in Response to Mitochondrial Oxidative Stress

Abstract

The mitochondrial permeability transition pore plays a key role in programmed cell death and the induction of autophagy. Opening of the pore is regulated by the mitochondrial peptidyl prolyl-cis, trans-isomerase cyclophilin D (CYPD). Previously it was shown in the aging model organism Podospora anserina that PaCYPD abundance increases during aging and that PaCypD overexpressors are characterized by accelerated aging. Here, we describe a role of PaCYPD in the regulation of autophagy. We found that the accelerated aging phenotype observed in a strain overexpressing PaCypD is not metacaspase-dependent but is accompanied by an increase of general autophagy and mitophagy, the selective autophagic degradation of mitochondria. It thus is linked to what has been defined as “autophagic cell death” or “type II” programmed cell death. Moreover, we found that the previously demonstrated age-related induction of autophagy in wild-type aging depends on the presence of PaCYPD. Deletion of PaCypD leads to a decrease in autophagy in later stages of age and under paraquat-mediated oxidative stress. Finally, we report that PaCYPD is also required for mitohormesis, the beneficial effect of mild mitochondrial stress. Thus, PaCYPD plays a key role in the context-dependent regulation of pathways leading to pro-survival and pro-death effects of autophagy.

Autophagy compensates impaired energy metabolism in CLPXP‐deficient Podospora anserina strains and extends healthspan

“…Next, we tested the impact of lowering mitophagy beyond the basic levels found in the ∆PaClpXP mutant. Therefore, we combined the PaClpXP deletion with the deletion of PaCypD , a gene coding for the mitochondrial peptidyl prolyl‐cis, trans‐isomerase cyclophilin D (CYPD) known to be involved in the regulation of mitochondrial permeability transition (mPT) regulation, programmed cell death (Brust et al ., ), and mitophagy (Carreira et al ., ; Kramer et al ., ). In the latter mutant, mitophagy levels are lower than the basal levels normally observed in P. anserina strains (Kramer et al ., ).…”

“…f). This reduction is similar to that in the previously reported ∆ PaCypD/PaSod3::Gfp strain (Kramer et al ., ). Interestingly, we found no obvious differences in the amount of superoxide but a slight decrease in hydrogen peroxide levels in a ∆PaClpXP/∆PaCypD mutant compared to the wild type and the single deletion mutants that probably could be co‐responsible for the healthier phenotype of this mutant (Fig.…”

Guidelines and recommendations on yeast cell death nomenclature

“…Another filamentous fungus, Podospora anserina , is used as an aging model that incorporates crucial apoptotic factors, including two metacaspases (PaMCA1 and PaMCA2) and at least five Aif members, of which only mitochondrial (but not cytosolic) isoforms seem to be relevant for aging-driven RCD 341 342 . A role for the P. anserina cyclophilin D ortholog in RCD 343 344 345 as well as for autophagy in aging and lifespan control of P. anserina 346 347 have been reported. Further instances of fungal RCD 306 348 have been documented in Paracoccidioides brasiliensis 349 , Colletotrichum gloeosporioides 350 , Fusarium oxysporum 351 , Fusarium graminearum 352 , Mucor racemosus 353 , Botrytis cinerea 354 , Penicillium expansum 355 , Rhizopus oryzae 356 , Scedosporium prolificans 357 and Neurospora crassa 358 .…”

AT 101 induces early mitochondrial dysfunction and HMOX1 (heme oxygenase 1) to trigger mitophagic cell death in glioma cells

“…DMEM GlutaMAX (10,566,016), SILAC DMEM (A33822), penicillin/streptomycin (15,140,122), L-glutamine (25,030,081), fetal bovine serum (FBS; 10,270,106), dialyzed FBS (26,400,044), phosphate buffered saline (PBS) (14,190,094) and trypsin-EDTA (25,200,056) were purchased from Gibco® (Life Technologies). L-arginine 13 C 6 , 15 N 4 ( NC0332135) and L-lysine 13 C 6 , 15 N 2 (NC0353871) were purchased from Cambridge Isotope laboratories and standard L-arginine (A5006) and L-lysine (L5501) from Sigma-Aldrich.…”

“…More recently, in the fungal aging model Podospora anserina it was demonstrated that under low stress autophagy acts as a prosurvival or 'longevity assurance pathway' allowing the fungus to reach a long lifespan [10][11][12]. However, after passing threshold levels of stress (e.g., oxidative stress, protein stress) autophagy turns to a pro-death pathway leading to ACD and a shortened lifespan [13,14].…”