To investigate the therapeutic potential of ANA-12 in restoring testicular health by modulating local neurochemical balance in adult rats of passive smoking, secondhand smoking or environmental tobacc Show more
To investigate the therapeutic potential of ANA-12 in restoring testicular health by modulating local neurochemical balance in adult rats of passive smoking, secondhand smoking or environmental tobacco smoke/nicotine exposure. Preclinical rodent models mimicking a real-life human smoking scenario. Post-acclimatization, adult male rats of 250-300 g body weight were randomized into passive smoking, oral nicotine, ANA-12 pre-treatment, and healthy unexposed controls. Rats were exposed to passive smoking through a whole-body inhalation chamber and oral nicotine through gavage with/without intraperitoneal administration of ANA-12 at differential dosages prior to passive smoking/nicotine exposure for a period of 4- and 12-week studies. Testes histopathology, DNA damage potency, and fertility indices alongside redox homeostasis and expressions of local neurotransmitter dopamine and its receptors D1 and D2, and neurotrophic factor, brain-derived neurotrophic factor (BDNF) and its receptor, tyrosine kinase beta (Trk-β) in testes, comet assay in whole blood, and serum cotinine levels. Compared with the healthy unexposed controls, passive smoking and oral nicotine exposure dose- and time-dependently disrupt developing spermatogonia, spermatocytes, and spermatids of the seminiferous tubules and basement membrane; reduce sperm count with concomitant higher deoxyribonucleic acid (DNA) damage; and upregulate BDNF/Trk-β and dopamine/D1 expressions, as well as oxidative stress with subsequent antioxidant depletion in testes. In contrast, regardless of the duration of exposure, ANA-12 pre-treatment significantly restores germ cells of the seminiferous epithelium, improves spermatogenesis, downregulates aberrant local neurochemical systems, and maintains redox homeostasis in the testicular milieu. These results are in accordance with the whole blood DNA damage and serum cotinine levels, a biomarker of nicotine exposure. The results offer a novel insight into therapeutic interventions for passive or secondhand smoking- or environmental tobacco smoke-induced male reproductive impairment via regulation of BDNF-dopaminergic signaling and antioxidant balance in testes by ANA-12, leading to improved fertility potential and overall testicular health, which could establish the modulation of the brain-testes axis, implicated in nicotine addiction. This study holds translational potential of ANA-12 for the management of smoking- or nicotine-related male infertility of individuals unable or unwilling to quit smoking. Show less
The RNA-binding ARS2 protein is centrally involved in both early RNA polymerase II (RNAPII) transcription termination and transcript decay. Despite its essential nature, the mechanisms by which ARS2 e Show more
The RNA-binding ARS2 protein is centrally involved in both early RNA polymerase II (RNAPII) transcription termination and transcript decay. Despite its essential nature, the mechanisms by which ARS2 enacts these functions have remained unclear. Here, we show that a conserved basic domain of ARS2 binds a corresponding acidic-rich, short linear motif (SLiM) in the transcription restriction factor ZC3H4. This interaction recruits ZC3H4 to chromatin to elicit RNAPII termination, independent of other early termination pathways defined by the cleavage and polyadenylation (CPA) and Integrator (INT) complexes. We find that ZC3H4, in turn, forms a direct connection to the nuclear exosome targeting (NEXT) complex, hereby facilitating rapid degradation of the nascent RNA. Hence, ARS2 instructs the coupled transcription termination and degradation of the transcript onto which it is bound. This contrasts with ARS2 function at CPA-instructed termination sites where the protein exclusively partakes in RNA suppression via post-transcriptional decay. Show less