Absence of TRIM32 Leads to Reduced GABAergic Interneuron Generation and Autism-like Behaviors in Mice via Suppressing mTOR Signaling

Abstract Mammalian target of rapamycin (mTOR) signaling plays essential roles in brain development. Hyperactive mTOR is an essential pathological mechanism in autism spectrum disorder (ASD). Here, we show that tripartite motif protein 32 (TRIM32), as a maintainer of mTOR activity through promoting the proteasomal degradation of G protein signaling protein 10 (RGS10), regulates the proliferation of medial/lateral ganglionic eminence (M/LGE) progenitors. Deficiency of TRIM32 results in an impaired generation of GABAergic interneurons and autism-like behaviors in mice, concomitant with an elevated autophagy, which can be rescued by treatment embryonically with 3BDO, an mTOR activator. Transplantation of M/LGE progenitors or treatment postnatally with clonazepam, an agonist of the GABAA receptor, rescues the hyperexcitability and the autistic behaviors of TRIM32−/− mice, indicating a causal contribution of GABAergic disinhibition. Thus, the present study suggests a novel mechanism for ASD etiology in that TRIM32 deficiency-caused hypoactive mTOR, which is linked to an elevated autophagy, leads to autism-like behaviors via impairing generation of GABAergic interneurons. TRIM32−/− mouse is a novel autism model mouse.

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Abnormal mTOR Activity in Pediatric Autoimmune Neuropsychiatric and MIA-Associated Autism Spectrum Disorders

International Journal of Molecular Sciences ◽

10.3390/ijms23020967 ◽

2022 ◽

Vol 23 (2) ◽

pp. 967

Author(s):

Ekaterina A. Trifonova ◽

Zakhar S. Mustafin ◽

Sergey A. Lashin ◽

Alex V. Kochetov

Keyword(s):

Autism Spectrum Disorder ◽

Autism Spectrum Disorders ◽

Environmental Factors ◽

Behavioral Problems ◽

Early Onset ◽

Mammalian Target Of Rapamycin ◽

Autism Spectrum ◽

Mtor Signaling ◽

Spectrum Disorders ◽

Mtor Activity

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by the early onset of communication and behavioral problems. ASD is highly heritable; however, environmental factors also play a considerable role in this disorder. A significant part of both syndromic and idiopathic autism cases could be attributed to disorders caused by mammalian target of rapamycin (mTOR)-dependent translation deregulation. This narrative review analyzes both bioinformatic and experimental evidence that connects mTOR signaling to the maternal autoantibody-related (MAR) autism spectrum and autoimmune neuropsychiatric disorders simultaneously. In addition, we reconstruct a network presenting the interactions between the mTOR signaling and eight MAR ASD genes coding for ASD-specific maternal autoantibody target proteins. The research discussed in this review demonstrates novel perspectives and validates the need for a subtyping of ASD on the grounds of pathogenic mechanisms. The utter necessity of designing ELISA-based test panels to identify all antibodies related to autism-like behavior is also considered.

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Role of PRAS40 in Akt and mTOR signaling in health and disease

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00660.2011 ◽

2012 ◽

Vol 302 (12) ◽

pp. E1453-E1460 ◽

Cited By ~ 92

Author(s):

Claudia Wiza ◽

Emmani B. M. Nascimento ◽

D. Margriet Ouwens

Keyword(s):

Mammalian Target Of Rapamycin ◽

Mtor Signaling ◽

Cellular Growth ◽

S6 Kinase ◽

Binding Partners ◽

Health And Disease ◽

Mtor Complex 1 ◽

Mtor Activity

The proline-rich Akt substrate of 40 kDa (PRAS40) acts at the intersection of the Akt- and mammalian target of rapamycin (mTOR)-mediated signaling pathways. The protein kinase mTOR is the catalytic subunit of two distinct signaling complexes, mTOR complex 1 (mTORC1) and mTORC2, that link energy and nutrients to the regulation of cellular growth and energy metabolism. Activation of mTOR in response to nutrients and growth factors results in the phosphorylation of numerous substrates, including the phosphorylations of S6 kinase by mTORC1 and Akt by mTORC2. Alterations in Akt and mTOR activity have been linked to the progression of multiple diseases such as cancer and type 2 diabetes. Although PRAS40 was first reported as substrate for Akt, investigations toward mTOR-binding partners subsequently identified PRAS40 as both component and substrate of mTORC1. Phosphorylation of PRAS40 by Akt and by mTORC1 itself results in dissociation of PRAS40 from mTORC1 and may relieve an inhibitory constraint on mTORC1 activity. Adding to the complexity is that gene silencing studies indicate that PRAS40 is also necessary for the activity of the mTORC1 complex. This review summarizes the regulation and potential function(s) of PRAS40 in the complex Akt- and mTOR-signaling network in health and disease.

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Gastric Mammalian Target of Rapamycin Signaling Regulates Ghrelin Production and Food Intake

Endocrinology ◽

10.1210/en.2009-0372 ◽

2009 ◽

Vol 150 (8) ◽

pp. 3637-3644 ◽

Cited By ~ 54

Author(s):

Geyang Xu ◽

Yin Li ◽

Wenjiao An ◽

Shenduo Li ◽

Youfei Guan ◽

...

Keyword(s):

Food Intake ◽

Energy Homeostasis ◽

Mammalian Target Of Rapamycin ◽

Reciprocal Relationship ◽

Mtor Signaling ◽

Target Of Rapamycin ◽

Energy Status ◽

Ghrelin Receptor ◽

Ghrelin Receptor Antagonist ◽

Mtor Activity

Ghrelin, a gastric hormone, provides a hunger signal to the central nervous system to stimulate food intake. Mammalian target of rapamycin (mTOR) is an intracellular fuel sensor critical for cellular energy homeostasis. Here we showed the reciprocal relationship of gastric mTOR signaling and ghrelin during changes in energy status. mTOR activity was down-regulated, whereas gastric preproghrelin and circulating ghrelin were increased by fasting. In db/db mice, gastric mTOR signaling was enhanced, whereas gastric preproghrelin and circulating ghrelin were decreased. Inhibition of the gastric mTOR signaling by rapamycin stimulated the expression of gastric preproghrelin and ghrelin mRNA and increased plasma ghrelin in both wild-type and db/db mice. Activation of the gastric mTOR signaling by l-leucine decreased the expression of gastric preproghrelin and the level of plasma ghrelin. Overexpression of mTOR attenuated ghrelin promoter activity, whereas inhibition of mTOR activity by overexpression of TSC1 or TSC2 increased its activity. Ghrelin receptor antagonist d-Lys-3-GH-releasing peptide-6 abolished the rapamycin-induced increment in food intake despite that plasma ghrelin remained elevated. mTOR is therefore a gastric fuel sensor whose activity is linked to the regulation of energy intake through ghrelin.

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Muscle mTORC1 suppression by IL-6 during cancer cachexia: a role for AMPK

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00410.2012 ◽

2013 ◽

Vol 304 (10) ◽

pp. E1042-E1052 ◽

Cited By ~ 64

Author(s):

James P. White ◽

Melissa J. Puppa ◽

Song Gao ◽

Shuichi Sato ◽

Stephen L. Welle ◽

...

Keyword(s):

Skeletal Muscle ◽

Cancer Cachexia ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Mammalian Target Of Rapamycin ◽

Mtor Signaling ◽

Glucose Administration ◽

Mtorc1 Signaling ◽

Dose Dependent ◽

Mtor Activity

Although catabolic signaling has a well-established role in muscle wasting during cancer cachexia, the suppression of anabolic signaling also warrants further investigation. In cachectic tumor-bearing mice, circulating IL-6 levels are associated with suppressed muscle protein synthesis and mTORC1 signaling. We have found AMPK and IGF-I/insulin signaling, two well-known regulators of the mammalian target of rapamycin (mTOR), are altered with the progression of cachexia. How IL-6 can induce suppression of mTORC1 signaling remains to be established. The purpose of this study was to examine mTOR complex 1 (mTORC1) activation and regulation by IL-6 during cancer cachexia. IL-6 effects on mTOR activation were examined in Apc Min/+ mouse skeletal muscle and C2C12 myotubes. Systemic IL-6 overexpression in Apc Min/+ mice produced a dose-dependent suppression of mTOR signaling that corresponded to induction of STAT3 and AMPK phosphorylation. This result was also evident in IL-6-treated myotubes. Basal mTOR activation and mTOR responsiveness to glucose administration were suppressed in cachectic skeletal muscle. However, insulin induction of mTOR activity was maintained in IL-6-treated myotubes. Whereas IL-6 suppression of myotube mTOR activity was rescued by AMPK inhibition, inhibition of STAT3 signaling was not sufficient to rescue IL-6 suppression of mTOR activity. Last, treadmill exercise training was able to prevent IL-6-induced inhibition of mTOR signaling in Apc Min/+ mice independently of activated STAT. In conclusion, we report dose-dependent suppression of mTOR activity by IL-6 and suppressed mTOR responsiveness to glucose administration in Apc Min/+ mice. IL-6 suppression of mTOR activity was dependent on AMPK activation and independent of STAT signaling in myotubes.

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REDD2 is enriched in skeletal muscle and inhibits mTOR signaling in response to leucine and stretch

AJP Cell Physiology ◽

10.1152/ajpcell.00464.2008 ◽

2009 ◽

Vol 296 (3) ◽

pp. C583-C592 ◽

Cited By ~ 42

Author(s):

Mitsunori Miyazaki ◽

Karyn A. Esser

Keyword(s):

Skeletal Muscle ◽

Mammalian Target Of Rapamycin ◽

Mechanical Stretch ◽

Mtor Signaling ◽

Negative Regulator ◽

Muscle Size ◽

Inhibitory Function ◽

Dna Damage Responses ◽

Si Rna ◽

Mtor Activity

The protein kinase mammalian target of rapamycin (mTOR) is well established as a key regulator of skeletal muscle size. In this study, we determined that the stress responsive gene REDD2 (regulated in development and DNA damage responses 2) is a negative regulator of mTOR signaling and is expressed predominantly in skeletal muscle. Overexpression of REDD2 in muscle cells significantly inhibited basal mTOR signaling and diminished the response of mTOR to leucine addition or mechanical stretch. The inhibitory function of REDD2 on mTOR signaling seems to be mediated downstream or independent of Akt signaling and upstream of Rheb (Ras homolog enriched in brain). Knock down of tuberous sclerosis complex 2 (TSC2) using small interfering (si)RNA potently activated mTOR signaling and was sufficient to rescue REDD2 inhibition of mTOR activity, suggesting that REDD2 functions by modulating TSC2 function. Immunoprecipitation assays demonstrated that REDD2 does not directly interact with either TSC1 or TSC2. However, we found that REDD2 forms a complex with 14-3-3 protein and that increasing expression of REDD2 acts to competitively dissociate TSC2 from 14-3-3 and inhibits mTOR signaling. These findings demonstrate that REDD2 is a skeletal muscle specific inhibitory modulator of mTOR signaling and identify TSC2 and 14-3-3 as key molecular links between REDD2 and mTOR function.

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Altered Expression of GABAergic Markers in the Forebrain of Young and Adult Engrailed-2 Knockout Mice

Genes ◽

10.3390/genes11040384 ◽

2020 ◽

Vol 11 (4) ◽

pp. 384

Author(s):

Giovanni Provenzano ◽

Angela Gilardoni ◽

Marika Maggia ◽

Mattia Pernigo ◽

Paola Sgadò ◽

...

Keyword(s):

Gaba Receptors ◽

Gaba Receptor ◽

Brain Regions ◽

Autism Spectrum ◽

Gabaergic Interneuron ◽

Gabaergic Interneurons ◽

Rt Pcr ◽

Altered Expression ◽

Gabaergic Neurotransmission ◽

Adult Mice

Impaired function of GABAergic interneurons, and the subsequent alteration of excitation/inhibition balance, is thought to contribute to autism spectrum disorders (ASD). Altered numbers of GABAergic interneurons and reduced expression of GABA receptors has been detected in the brain of ASD subjects and mouse models of ASD. We previously showed a reduced expression of GABAergic interneuron markers parvalbumin (PV) and somatostatin (SST) in the forebrain of adult mice lacking the Engrailed2 gene (En2-/- mice). Here, we extended this analysis to postnatal day (P) 30 by using in situ hybridization, immunohistochemistry, and quantitative RT-PCR to study the expression of GABAergic interneuron markers in the hippocampus and somatosensory cortex of En2-/- and wild type (WT) mice. In addition, GABA receptor subunit mRNA expression was investigated by quantitative RT-PCR in the same brain regions of P30 and adult En2-/- and WT mice. As observed in adult animals, PV and SST expression was decreased in En2-/- forebrain of P30 mice. The expression of GABA receptor subunits (including the ASD-relevant Gabrb3) was also altered in young and adult En2-/- forebrain. Our results suggest that GABAergic neurotransmission deficits are already evident at P30, confirming that neurodevelopmental defects of GABAergic interneurons occur in the En2 mouse model of ASD.

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GABAergic cell loss in mice lacking autism-associated geneSema6A

10.1101/663419 ◽

2019 ◽

Author(s):

Karlie Menzel ◽

Gábor Szabó ◽

Yuchio Yanagawa ◽

Turhan Cocksaygan ◽

Céline Plachez

Keyword(s):

Brain Development ◽

Neuronal Networks ◽

Cell Loss ◽

Cell Number ◽

Autism Spectrum ◽

Mutant Mice ◽

Gabaergic Interneuron ◽

Gabaergic Interneurons ◽

Neuronal Connectivity ◽

Histological Techniques

AbstractBackgroundDuring brain development, a multitude of neuronal networks form as neurons find their correct position within the brain and send out axons to synapse onto specific targets. Altered neuronal connectivity within these complex networks has been reported in Autism Spectrum Disorder (ASD), leading to alterations in brain function and multisensory integration. Semaphorins (also referred to as Semas), a large protein family of about 30 members, have been shown to play an important role in neuronal circuit formation and have been implicated in the etiology of ASD. The purpose of the current study is to investigate howSema6Amutation affects neuronal connectivity in ASD. SinceSema6Ais involved in cell migration, we hypothesized that during brain development the migration of GABAergic interneurons is affected by the loss ofSema6Agene, leading to alterations in Excitatory/Inhibitory (E/I) balance.MethodsSema6Atransgenic mice were crossed with either GAD65-GFP mice or GAD67-GFP mice to allow for both a reliable and robust staining of the GABAergic interneuron population within theSema6Amouse line. Using histological techniques we studies the expression of interneurons subtypes in the Sema6A mutant mice.ResultsAnalysis ofSema6Amutant mice crossed with either GAD65-GFP or GAD67-GFP knock-in mice revealed a reduced number of GABAergic interneurons in the primary somatosensory cortex, hippocampus, and reticular thalamic nucleus (RTN) in adultSema6Amutant mice. This reduction in cell number appeared to be targeted to the Parvalbumin (PV) interneuron cell population since neither the Calretinin nor the Calbindin expressing interneurons were affected by theSema6Amutation.LimitationsAlthough the use of animal models has been crucial for understanding the biological basis of autism, the complexity of the human brain can never truly be replicated by these models.ConclusionsTaken together, these findings suggest thatSema6Agene loss affects only the fast spiking-PV population and reveal the importance of an axon guidance molecule in the formation of GABAergic neuronal networks and provide insight into the molecular pathways that may lead to altered neuronal connectivity and E/I imbalance in ASD.

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Gastric Mammalian Target of Rapamycin Signaling Contributes to Inhibition of Ghrelin Expression Induced by Roux-En-Y Gastric Bypass

Cellular Physiology and Biochemistry ◽

10.1159/000495325 ◽

2018 ◽

Vol 51 (2) ◽

pp. 664-680

Author(s):

Danjie Li ◽

Shaojian Li ◽

Qinling Pan ◽

Hening Zhai ◽

Miao Peng ◽

...

Keyword(s):

Gastric Bypass ◽

Ribosomal Protein ◽

Mammalian Target Of Rapamycin ◽

Mtor Signaling ◽

Target Of Rapamycin ◽

Mrna Levels ◽

Human Beings ◽

Protein Subunit ◽

Rapid Improvement ◽

Mtor Activity

Background/Aims: Roux-en-Y Gastric Bypass, RYGB, is the most effective strategy to control body weight in morbid obesity. RYGB leads to rapid improvement of glycemic status and weight loss, which are largely attributed to the alteration of gastrointestinal hormones including ghrelin. The current study examined potential mechanisms of altered ghrelin synthesis after RYGB. Methods: Gastric mammalian target of rapamycin (mTOR) signaling, ghrelin synthesis and secretion were determined in lean or obese male mice with or without RYGB operation, as well as in obese patients pre- and post-RYGB surgery. Ghrelin expression and mTOR signaling were investigated by western blotting and immunohistochemistry. Ghrelin mRNA levels were detected by real-time PCR. Plasma ghrelin was measured by enzyme immunoassay. Results: mTOR activity in the gastric fundus was significantly lower than in the forestomachs. Both of them were decreased after 24h fasting. A significant negative correlation was found between gastric levels of phospho-S6 (phospho-S6 ribosomal protein) and proghrelin during changes of energy status. mTOR activity was activated, whereas ghrelin expression was inhibited by Roux-en-Y Gastric Bypass in both rodents and human beings. Increment of ghrelin synthesis and decline of mTOR signaling induced by rapamycin were significantly reversed by RYGB in both lean and obese mice. Administration of Ad-S6K1 (adenovirus-mediated p70 ribosomal protein subunit 6 kinase 1) from tail vein suppressed the expression of ghrelin in RYGB-operated mice relative to control animals. Conclusion: mTOR is therefore a gastric fuel sensor whose activity is linked to the regulation of ghrelin after Roux-en-Y Gastric Bypass.

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Targeting mammalian target of rapamycin: prospects for the treatment of inflammatory bowel diseases

Current Medicinal Chemistry ◽

10.2174/0929867327666200504081503 ◽

2020 ◽

Vol 27 ◽

Author(s):

Naser-Aldin Lashgari ◽

Nazanin Momeni Roudsari ◽

Saeideh Momtaz ◽

Negar Ghanaatian ◽

Parichehr Kohansal ◽

...

Keyword(s):

Signaling Pathway ◽

Mammalian Target Of Rapamycin ◽

Mtor Pathway ◽

Mtor Signaling ◽

Target Of Rapamycin ◽

In Vivo Studies ◽

Cochrane Library ◽

Mtor Signaling Pathway ◽

Inflammatory Bowel

: Inflammatory bowel disease (IBD) is a general term for a group of chronic and progressive disorders. Several cellular and biomolecular pathways are implicated in the pathogenesis of IBD, yet the etiology is unclear. Activation of the mammalian target of rapamycin (mTOR) pathway in the intestinal epithelial cells was also shown to induce inflammation. This review focuses on the inhibition of the mTOR signaling pathway and its potential application in treating IBD. We also provide an overview on plant-derived compounds that are beneficial for the IBD management through modulation of the mTOR pathway. Data were extracted from clinical, in vitro and in vivo studies published in English between 1995 and May 2019, which were collected from PubMed, Google Scholar, Scopus and Cochrane library databases. Results of various studies implied that inhibition of the mTOR signaling pathway downregulates the inflammatory processes and cytokines involved in IBD. In this context, a number of natural products might reverse the pathological features of the disease. Furthermore, mTOR provides a novel drug target for IBD. Comprehensive clinical studies are required to confirm the efficacy of mTOR inhibitors in treating IBD.

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Minocycline inhibits mTOR signaling activation and alleviates behavioral deficits in the Wistar rats with acute ischemia stroke

CNS & Neurological Disorders - Drug Targets ◽

10.2174/1871527319999200831153748 ◽

2020 ◽

Vol 19 ◽

Author(s):

Shengyuan Wang ◽

Chuanling Wang ◽

Lihua Wang ◽

Zhiyou Cai

Keyword(s):

Cerebral Ischemia ◽

Ischemia Reperfusion ◽

Mammalian Target Of Rapamycin ◽

Mtor Signaling ◽

Acute Ischemia ◽

Intragastric Administration ◽

Underlying Mechanisms ◽

Signaling Activation ◽

The Brain ◽

Minocycline Therapy

Background: Mammalian target of rapamycin (mTOR) has been evidenced as a multimodal therapy in the path-ophysiological process of acute ischemic stroke (AIS). However, the pathway that minocycline targets mTOR signaling is not fully defined in the AIS pathogenesis. This study is to aim at the effects of minocycline on the mTOR signaling in the AIS process and further discover the underlying mechanisms of minocycline involved in the following change of mTOR signaling-autophagy. Methods: Cerebral ischemia/reperfusion (CIR) rat animal models were established with the transient suture occlusion into middle cerebral artery. Minocycline (50mg/kg) was given by intragastric administration. The Morris water maze was used to test the cognitive function of animals. Immunohistochemistry and immunofluorescence were introduced for testing the lev-els of synaptophysin and PSD-95. Western blot was conducted for investigating the levels of mTOR, p-mTOR (Ser2448), p70S6, p-p70S6 (Thr389), eEF2k, p-eEF2k (Ser366), p-eIF4B (Ser406), LC3, p62, synaptophysin and PSD-95. Results: Minocycline prevents cognitive decline of the MCAO stroke rats. Minocycline limits the expression of p-mTOR (Ser2448) and the downstream targets of mTOR [p70S6, p-p70S6 (Thr389), eEF2k, p-eEF2k (Ser366) and p-eIF4B (Ser406)] (P<0.01), while minocycline has no influence on mTOR. LC3-II abundance and the LC3-II/I ratio were upregu-lated in the hippocampus of the MCAO stroke rats by the minocycline therapy (P<0.01). p62 was downregulated in the hippocampus from the MCAO stroke rats administrated with minocycline therapy(P<0.01). The levels of SYP and PSD-95 were up-regulated in the brain of the MCAO stroke rats administrated with minocycline therapy. Conclusion: Minocycline prevents cognitive deficits via inhibiting mTOR signaling and enhancing autophagy process, and promoting the expression of pre-and postsynaptic proteins (synaptophysin and PSD-95) in the brain of the MCAO stroke rats. The potential neuroprotective role of minocycline in the process of cerebral ischemia may be related to mitigating is-chemia-induced synapse injury via inhibiting activation of mTOR signaling.

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