PI3K/AKT/mTOR Signalling Inhibitor Chrysophanol Ameliorates Neurobehavioural and Neurochemical Defects in Propionic Acid-induced Experimental Model of Autism in Adult Rats

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder marked by social and communication deficits as well as repetitive behaviour. Several studies have found that overactivation of the PI3K/AKT/mTOR signalling pathways during brain development plays a significant role in autism pathogenesis. Overexpression of the PI3K/AKT/mTOR signalling pathway causes neurological disorders by increasing cell death, neuroinflammation, and oxidative stress. Chrysophanol, also known as chrysophanic acid, is a naturally occurring chemical obtained from the plant Rheum palmatum. This study aimed to examine the neuroprotective effect of CPH on neurobehavioral, molecular, neurochemical, and gross pathological alterations in ICV-PPA induced experimental model of autism in adult rats. The effects of ICV-PPA on PI3K/AKT/mTOR downregulation in the brain were studied in autism-like rats. Furthermore, we investigated how CPH affected myelin basic protein (MBP) levels in rat brain homogenate and apoptotic biomarkers such as caspase-3, Bax, and Bcl-2 levels in rat brain homogenate and blood plasma samples. Rats were tested for behavioural abnormalities such as neuromuscular dysfunction using an actophotometer, motor coordination using a beam crossing task (BCT), depressive behaviour using a forced swim test (FST), cognitive deficiency, and memory consolidation using a Morris water maze (MWM) task. In PPA-treated rats, prolonged oral CPH administration from day 12 to day 44 of the experimental schedule reduces autistic-like symptoms. Furthermore, in rat brain homogenates, blood plasma, and CSF samples, cellular, molecular, and cell death markers, neuroinflammatory cytokines, neurotransmitter levels, and oxidative stress indicators were investigated. The recent findings imply that CPH also restores abnormal neurochemical levels and may prevent autism-like gross pathological alterations, such as demyelination volume, in the rat brain.

Tenofovir disoproxil fumarate directly ameliorates liver fibrosis by inducing hepatic stellate cell apoptosis via downregulation of PI3K/Akt/mTOR signaling pathway

Background Antifibrotic agent for the treatment of liver fibrosis has not been developed so far. Long term treatment of chronic hepatitis B patients with antiviral drugs tenofovir disoproxil fumarate (TDF) and entecavir (ETV) results in the regression of liver fibrosis, but the underlying mechanism has not been clarified. Therefore, we aimed to investigate the direct impact of TDF and ETV on liver fibrosis. Methods Activated hepatic stellate cell (HSC) cell lines were used to evaluate the effects of TDF and ETV. After treatment with each antiviral agent, cell viability, morphology, apoptotic features, autophagy and antifibrosis signalling pathways were examined. Then, collagen deposition, fibrosis markers and activated HSCs were measured in liver tissues of the liver fibrosis model mice. Results After TDF treatment, the viabilities of LX2 and HSC-T6 cells were decreased, and the cells exhibited apoptotic features, but ETV did not induce these effects. Cleavage of PARP and Caspase-3 and the inhibition of the antiapoptotic gene Bcl-xl indicated activated HSC apoptosis following TDF treatment. TDF simultaneously increased autophagy, which also regulated apoptosis through crosstalk. TDF inactivated the PI3K/Akt/mTOR signalling pathway, which was associated with the activation of both apoptosis and autophagy. In the liver fibrosis mouse model, the fibrotic area and activated HSC markers were decreased by TDF but not ETV treatment. Additionally, apoptotic cells were concentrated in the periportal fibrotic area after TDF treatment, which indicated the specific antifibrotic effect of TDF. Conclusions TDF directly ameliorates liver fibrosis by downregulating the PI3K/Akt/mTOR signalling pathway, which results in the apoptosis of activated HSCs. The antifibrotic effects of TDF indicate that it may be a therapeutic agent for the treatment of liver fibrosis.

Negatively Regulated by miR-29c-3p, MTFR1 Promotes the Progression and Glycolysis in Lung Adenocarcinoma via the AMPK/mTOR Signalling Pathway

Background: Lung adenocarcinoma (LUAD) is the major form of lung cancer that presents a major peril to public health. Owing to the high rates of morbidity, mortality and chemoresistance, it is necessary to develop more effective therapeutic targets of LUAD. Mitochondrial fission regulator 1 (MTFR1) affects the occurrence and development of some diseases by regulating mitochondrial dynamics and is dysregulated in LUAD. However, the functions and molecular mechanisms of MTFR1 in LUAD have not been investigated.Methods: Immunohistochemical (IHC) analysis, real-time quantitative polymerase chain reaction (RT-qPCR), bioinformatic analysis and western blot (WB) were performed to assess the expression of MTFR1 at both protein and mRNA levels. The biological functions of MTFR1 in LUAD cells were assessed based on various in vivo and in vitro experiments. The dual-luciferase reporter assay and some rescue experiments were performed to evaluate the underlying mechanism of MTFR1 in LUAD.Results: MTFR1 was upregulated in LUAD cells and tissues and correlated with dismal clinicopathologic features and a worse prognosis of patients with LUAD. Functionally, MTFR1 overexpression stimulated the proliferation, invasion, migration and glycolytic capacity and impeded the apoptosis of LUAD cells; however, opposite results were obtained when MTFR1 expression was knocked down. MTFR1, which was directly targeted by miR-29c-3p, may exert its biological functions through the AMPK/mTOR signalling pathway.Conclusion: MTFR1 promotes the progression of LUAD. Therefore, targeting MTFR1 can offer an effective therapeutic strategy for LUAD treatment.

Infection-induced miR-126 suppresses tsc1- and cxcl12a-dependent permissive macrophages during mycobacterial infection

Regulation of host microRNA (miRNA) expression is a contested node that controls the host immune response to mycobacterial infection. The host must overcome concerted subversive efforts of pathogenic mycobacteria to launch and maintain a protective immune response. Here we examine the role of miR-126 in the zebrafish model of Mycobacterium marinum infection and identify a protective role for this infection-induced miRNA through multiple effector pathways. Specifically, we analyse the impact of the miR-126 knockdown-induced tsc1a and cxcl12a/ccl2/ccr2 signalling axes during early host-M. marinum interactions. We find a strong detrimental effect of tsc1a upregulation that renders zebrafish embryos susceptible to higher bacterial burden and increased cell death despite dramatically higher recruitment of macrophages to the site of infection. We demonstrate that infection-induced miR-126 suppresses tsc1 and cxcl12a expression thus improving macrophage function early in infection, partially through activation of mTOR signalling and strongly through preventing the recruitment of Ccr2+ permissive macrophages, resulting in the recruitment of protective tnfa-expressing macrophages. Together our results demonstrate an important role for infection-induced miR-126 in shaping an effective immune response to M. marinum infection in zebrafish embryos.

EWAS of Monozygotic Twins Implicate a Role of mTOR Pathway in Pathogenesis of Tic Spectrum Disorder

Tic spectrum disorder (TSD) is an umbrella term which includes Gilles de la Tourette syndrome (GTS) and chronic tic disorder (CTD). They are considered highly heritable, yet the genetic components remain largely unknown. In this study we aimed to investigate disease-associated DNA methylation differences to identify genes and pathways which may be implicated in TSD aetiology. For this purpose, we performed an exploratory analysis of the genome-wide DNA methylation patterns in whole blood samples of 16 monozygotic twin pairs, of which eight were discordant and six concordant for TSD, while two pairs were asymptomatic. Although no sites reached genome-wide significance, we identified several sites and regions with a suggestive significance, which were located within or in the vicinity of genes with biological functions associated with neuropsychiatric disorders. The two top genes identified (TSC1 and CRYZ/TYW3) and the enriched pathways and components (phosphoinosides and PTEN pathways, and insulin receptor substrate binding) are related to, or have been associated with, the PI3K/AKT/mTOR pathway. Genes in this pathway have previously been associated with GTS, and mTOR signalling has been implicated in a range of neuropsychiatric disorders. It is thus possible that altered mTOR signalling plays a role in the complex pathogenesis of TSD.

Isonicotinylation is a histone mark induced by the anti-tuberculosis first-line drug isoniazid

Isoniazid (INH) is a first-line anti-tuberculosis drug used for nearly 70 years. However, the mechanism underlying the side effects of INH has remained elusive. Here, we report that INH and its metabolites induce a post-translational modification (PTM) of histones, lysine isonicotinylation (Kinic), also called 4-picolinylation, in cells and mice. INH promotes the biosynthesis of isonicotinyl-CoA (Inic-CoA), a co-factor of intracellular isonicotinylation. Mass spectrometry reveals 26 Kinic sites in histones in HepG2 cells. Acetyltransferases CREB-binding protein (CBP) and P300 catalyse histone Kinic, while histone deacetylase HDAC3 functions as a deisonicotinylase. Notably, MNase sensitivity assay and RNA-seq analysis show that histone Kinic relaxes chromatin structure and promotes gene transcription. INH-mediated histone Kinic upregulates PIK3R1 gene expression and activates the PI3K/Akt/mTOR signalling pathway in liver cancer cells, linking INH to tumourigenicity in the liver. We demonstrate that Kinic is a histone acylation mark with a pyridine ring, which may have broad biological effects. Therefore, INH-induced isonicotinylation potentially accounts for the side effects in patients taking INH long-term for anti-tuberculosis therapy, and this modification may increase the risk of cancer in humans.