Tranylcypromine upregulates Sestrin 2 expression to ameliorate NLRP3-related noise-induced hearing loss

Noise-induced hearing loss is the primary non-genetic factor contributing to auditory dysfunction.However,there are currently no effective pharmacological interventions for patients with noise-induced hearing loss.Here,we present evidence suggesting that the lysine-specific demethylase 1 inhibitor–tranylcypromine is an otoprotective agent that could be used to treat noise-induced hearing loss,and elucidate its underlying regulatory mechanisms.We established a mouse model of permanent threshold shift hearing loss by exposing the mice to white broadband noise at a sound pressure level of 120 d B for 4 hours.We found that tranylcypromine treatment led to the upregulation of Sestrin2(SESN2)and activation of the autophagy markers light chain 3B and lysosome-associated membrane glycoprotein 1 in the cochleae of mice treated with tranylcypromine.The noise exposure group treated with tranylcypromine showed significantly lower average auditory brainstem response hearing thresholds at click,4,8,and 16 k Hz frequencies compared with the noise exposure group treated with saline.These findings indicate that tranylcypromine treatment resulted in increased SESN2,light chain 3B,and lysosome-associated membrane glycoprotein 1 expression after noise exposure,leading to a reduction in levels of 4-hydroxynonenal and cleaved caspase-3,thereby reducing noise-induced hair cell loss.Additionally,immunoblot analysis demonstrated that treatment with tranylcypromine upregulated SESN2 expression via the autophagy pathway.Tranylcypromine treatment also reduced the production of NOD-like receptor family pyrin domaincontaining 3(NLRP3)production.In conclusion,our results showed that tranylcypromine treatment ameliorated cochlear inflammation by promoting the expression of SESN2,which induced autophagy,thereby restricting NLRP3-related inflammasome signaling,alleviating cochlear hair cell loss,and protecting hearing function.These findings suggest that inhibiting lysine-specific demethylase 1 is a potential therapeutic strategy for preventing hair cell loss and noise-induced hearing loss.

Discovery of novel phosphodiesterase-1 inhibitors for curing vascular dementia:Suppression of neuroinflammation by blocking NF-κB transcription regulation and activating cAMP/CREB axis

Vascular dementia(VaD)is the second commonest type of dementia which lacks of efficient treatments currently.Neuroinflammation as a prominent pathological feature of VaD,is highly involved in the development of VaD.In order to verify the therapeutic potential of PDE1 inhibitors against VaD,the anti-neuroinflammation,memory and cognitive improvement were evaluated in vitro and in vivo by a potent and selective PDE1 inhibitor 4a.Also,the mechanism of 4a in ameliorating neuroinflammation and VaD was systematically explored.Furthermore,to optimize the drug-like properties of 4a,especially for metabolic stability,15 derivatives were designed and synthesized.As a result,candidate 5f,with a potent IC50 value of 4.5 nmol/L against PDE1C,high selectivity over PDEs,and remarkable metabolic stability,efficiently ameliorated neuron degeneration,cognition and memory impairment in VaD mice model by suppressing NF-κB transcription regulation and activating cAMP/CREB axis.These results further identified PDE1 inhibition could serve as a new therapeutic strategy for treatment of VaD.

In vitro and in vivo efficacy of Molnupiravir against Zika virus infections

Dear Editor,Zika virus(ZIKV)is a mosquito-borne,positive-stranded RNA virus first identified in 1947 in monkeys and later identified in humans in 1952(Faye et al.,2014).It is among the“TORCH”group of microorganisms and causes outbreaks in several countries and regions since 2007(Voordouw et al.,2019).