Cocaine Modulates the Neuronal Endosomal System and Extracellular Vesicles in a Sex-Dependent Manner

Abstract

In multiple neurodevelopmental and neurodegenerative disorders, endosomal changes correlate with changes in exosomes. We examined this linkage in the brain of mice that received cocaine injections for two weeks starting at 2.5 months of age. Cocaine caused a decrease in the number of both neuronal early and late endosomes and exosomes in the brains of male but not female mice. The response to cocaine in ovariectomized females mirrored male, demonstrating that these sex-differences in response to cocaine are driven by hormonal differences. Moreover, cocaine increased the amount of α-synuclein per exosome in the brain of females but did not affect exosomal α-synuclein content in the brain of males, a sex-difference eliminated by ovariectomy. Enhanced packaging of α-synuclein into female brain exosomes with the potential for propagation of pathology throughout the brain suggests a mechanism for the different response of females to chronic cocaine exposure as compared to males.

Cocaine perturbs mitovesicle biology in the brain

“…As assessed by Western blot analysis (Figure 1a), with our fractionation system microvesicle proteins, such as Annexin A2, were enriched in low‐density fractions (with the highest signal in fractions 1–3) while exosome proteins, such as ALIX, were mainly found in the intermediate‐density fractions 4–6 (with a minor presence in fractions 3 and 7), consistent with previous reports (Barreto et al., 2022; Jeppesen et al., 2019; D'Acunzo et al, 2021, 2022). The brain EVs in the highest density fractions, particularly in Fr8, were largely negative for microvesicle and exosome proteins and contained mitovesicles, as assessed by the levels of mitochondrial proteins such as PDHE1α, found in the mitovesicle matrix (MMx), COX‐IV, found in the inner mitovesicle membrane (IMM), and VDAC, found in the outer mitovesicle membrane (OMM).…”

“…We have previously shown that chronic cocaine exposure alters the levels and cargo of exosomes in a sex‐dependent fashion (Barreto et al., 2022; Landfield et al., 2021). In addition, we (D'Acunzo et al., 2021) and others (Rosina et al., 2022) showed higher secretion of mitovesicles into the extracellular space under conditions with mitochondrial damage, likely a compensatory mechanism to avoid the accumulation of toxic and oxidised mitochondrial components within the cell.…”

Sex Differentially Alters Secretion of Brain Extracellular Vesicles During Aging: A Potential Mechanism for Maintaining Brain Homeostasis

“…2 c , 2d, and 2e ). We also found that the level of the exosome intraluminal marker HSC70 [ 11 ] significantly increased with age only in the brains of female mice (female: p = 0.0134; male: p = 0.6365) ( Fig. 2 c and 2f ).…”

“…They are informative of the health of the endosomal-lysosomal pathway and changes that occur in multiple disorders, including spinocerebellar ataxia [ 4 ] and aging-dependent neurodegenerative diseases, such as Down syndrome (DS), Alzheimer’s disease (AD) and Parkinson disease (PD) [ 5 ]. For example, the interrelationship between endosomal pathology and the level of release and content of exosomes was demonstrated in DS [ 6 – 8 ] and the brain of carriers of the apolipoprotein E4 allele, the major risk factor for AD [ 9 , 10 ] as well as in mice chronically intoxicated with cocaine [ 11 ]. Mitovesicles, which were recently identified in our laboratory, originate from mitochondria, with size similar to exosomes and are informative of the oxidative status of the cell and of mitochondrial metabolic dysfunctions, such as in DS [ 8 ].…”

Heterozygote Dopamine Transporter Knockout Rats Display Enhanced Cocaine Locomotion in Adolescent Females

“…One additional explanation for the effects of α-Syn on the DA system is via α-Syn effects decreasing DAT [ 74 ]. A recent study highlighted the role that sex and α-Syn can have in responses to cocaine; cocaine only increased exosome α-Syn in female brains but not in males, effects that were neutralized by ovariectomy [ 75 ]. In our study, we found reduced α-Syn monomer in HET and KO female rats but no significant effects in HET males.…”