Fear-related disorders, including post-traumatic stress disorder (PTSD), and anxiety disorders are pervasive psychiatric conditions marked by persistent fear, stemming from its dysregulated acquisition and extinction. The primary treatment for these disorders, exposure therapy (ET), relies heavily on fear extinction (FE) principles. Adolescence, a vulnerable period for developing psychiatric disorders, is characterized by neurobiological changes in the fear circuitry, leading to impaired FE and increased susceptibility to relapse following ET. Ketamine, known for relieving anxiety and reducing PTSD symptoms, influences fear-related learning processes and synaptic plasticity across the fear circuitry. Our study aimed to investigate the effects of ketamine (10 mg/kg) on FE in adolescent male C57 BL/6 mice at the behavioral and molecular levels. We analyzed the protein and gene expression of synaptic plasticity markers in the hippocampus (HPC) and prefrontal cortex (PFC) and sought to identify neural correlates associated with ketamine\'s effects on adolescent extinction learning. Ketamine ameliorated FE in the adolescent males, likely affecting the consolidation and/or recall of extinction memory. Ketamine also increased the Akt and mTOR activity and the GluA1 and GluN2A levels in the HPC and upregulated BDNF exon IV mRNA expression in the HPC and PFC of the fear-extinguished mice. Furthermore, ketamine increased the c-Fos expression in specific brain regions, including the ventral HPC (vHPC) and the left infralimbic ventromedial PFC (IL vmPFC). Providing a comprehensive exploration of ketamine\'s mechanisms in adolescent FE, our study suggests that ketamine\'s effects on FE in adolescent males are associated with the activation of hippocampal Akt-mTOR-GluA1 signaling, with the vHPC and the left IL vmPFC as the proposed neural correlates.

Embryonic stem cells (ESCs) are defined as stem cells with self-renewing and differentiation capabilities. These unique properties are tightly regulated and controlled by complex genetic and molecular mechanisms, whose understanding is essential for both basic and translational research. A large number of studies have mostly focused on understanding the molecular mechanisms governing pluripotency and differentiation of ESCs, while the regulation of proliferation has received comparably less attention. Here, we investigate the role of ZZZ3 (zinc finger ZZ-type containing 3) in human ESCs homeostasis. We found that knockdown of ZZZ3 negatively impacts ribosome biogenesis, translation, and mTOR signaling, leading to a significant reduction in cell proliferation. This process occurs without affecting pluripotency, suggesting that ZZZ3-depleted ESCs enter a \"dormant-like\" state and that proliferation and pluripotency can be uncoupled also in human ESCs.

Epilepsy is a neurological disorder characterized by spontaneous and recurring seizures. It poses significant therapeutic challenges due to diverse etiology, pathobiology, and pharmacotherapy-resistant variants. The anticonvulsive effects of herbal leads with biocompatibility and toxicity considerations have attracted much interest, inspiring mechanistic analysis with the view of their use for engagement of new targets and combination with antiseizure pharmacotherapies. This article presents a comprehensive overview of the key molecular players and putative action mechanisms of the most common antiepileptic herbals demonstrated in tissue culture and preclinical models. From the review of the literature, it emerges that their effects are mediated via five distinct mechanisms: (1) reduction of membrane excitability through inhibition of cation channels, (2) improvement of mitochondrial functions with antioxidant effects, (3) enhancement in synaptic transmission mediated by GABAA receptors, (4) improvement of immune response with anti-inflammatory action, and (5) suppression of protein synthesis and metabolism. While some of the primary targets and action mechanisms of herbal anticonvulsants (1, 3) are shared with antiseizure pharmacotherapies, herbal leads also engage with distinct mechanisms (2, 4, and 5), suggesting new drug targets and opportunities for their integration with antiseizure medications. Addressing outstanding questions through research and in silico modeling should facilitate the future use of herbals as auxiliary therapy in epilepsy and guide the development of treatment of pharmacoresistant seizures through rigorous trials and regulatory approval.

Polyploidy is typically described as the condition wherein a cell or organism has more than two complete sets of chromosomes. Occurrence of polyploidy is a naturally occurring phenomenon in the body\'s development and differentiation processes under normal physiological conditions. However, in pathological conditions, the occurrence of polyploidy is documented in numerous disorders, including cancer, aging and diabetes. Due to the frequent association that the polyploidy has with these pathologies and physiological process, understanding the cause and consequences of polyploidy would be beneficial to develop potential therapeutic applications. Many of the genetic and epigenetic alterations leading to cancer, diabetes and aging are linked to signaling pathways. Nonetheless, the specific signaling pathway associated with the cause and consequences of polyploidy still remains largely unknown. Mammalian/mechanistic target of rapamycin (mTOR) plays a key role in the coordination between eukaryotic cell growth and metabolism, thereby simultaneously respond to various environmental inputs including nutrients and growth factors. Extensive research over the past two decades has established a central role for mTOR in the regulation of many fundamental cellular processes that range from protein synthesis to autophagy. Dysregulated mTOR signaling has been found to be implicated in various disease progressions. Importantly, there is a strong correlation between the hallmarks of polyploidy and dysregulated mTOR signaling. In this review, we explore and discuss the molecular connection between mTOR signaling and polyploidy along with its association with cancer, diabetes and aging. Additionally, we address some unanswered questions and provide recommendations to further advance our understanding of the intricate relationship between mTOR signaling and polyploidy.

mEAK-7 (mammalian EAK-7 or MTOR-associated protein, eak-7 homolog), is an evolutionarily conserved lysosomal membrane protein that is highly expressed in several cancer cells. Multiple recent studies have identified mEAK-7 as a positive activator of mTOR (mammalian/mechanistic target of rapamycin) signaling via an alternative mTOR complex, implying that mEAK-7 plays an important role in the promotion of cancer proliferation and migration. In addition, structural analyses investigating interactions between mEAK-7 and V-ATPase, a protein complex responsible for regulating pH homeostasis in cellular compartments, have suggested that mEAK-7 may contribute to V-ATPase-mediated mTORC1 activation. The C-terminal α-helix of mEAK-7 binds to the D and B subunits of the V-ATPase, creating a pincer-like grip around its B subunit. This binding undergoes partial disruption during ATP hydrolysis, potentially enabling other proteins such as mTOR to bind to the α-helix of mEAK-7. mEAK-7 also promotes chemoresistance and radiation resistance by sustaining DNA damage-mediated mTOR signaling through interactions with DNA-PKcs (DNA-dependent protein kinase catalytic subunit). Taken together, these findings indicate that mEAK-7 may be a promising therapeutic target against tumors. However, the precise molecular mechanisms and signal transduction pathways of mEAK-7 in cancer remain largely unknown, motivating the need for further investigation. Here, we summarize the current known roles of mEAK-7 in normal physiology and cancer development by reviewing the latest studies and discuss potential future developments of mEAK-7 in targeted cancer therapy.

Tertiary lymphoid structure (TLS) can predict the prognosis and sensitivity of tumors to immune checkpoint inhibitors (ICIs) therapy, whether it can be noninvasively predicted by radiomics in hepatocellular carcinoma with liver transplantation (HCC-LT) has not been explored. In this study, it is found that intra-tumoral TLS abundance is significantly correlated with recurrence-free survival (RFS) and overall survival (OS). Tumor tissues with TLS are characterized by inflammatory signatures and high infiltration of antitumor immune cells, while those without TLS exhibit uncontrolled cell cycle progression and activated mTOR signaling by bulk and single-cell RNA-seq analyses. The regulators involved in mTOR signaling (RHEB and LAMTOR4) and S-phase (RFC2, PSMC2, and ORC5) are highly expressed in HCC with low TLS. In addition, the largest cohort of HCC patients is studied with available radiomics data, and a classifier is built to detect the presence of TLS in a non-invasive manner. The classifier demonstrates remarkable performance in predicting intra-tumoral TLS abundance in both training and test sets, achieving areas under receiver operating characteristic curve (AUCs) of 92.9% and 90.2% respectively. In summary, the absence of intra-tumoral TLS abundance is associated with mTOR signaling activation and uncontrolled cell cycle progression in tumor cells, indicating unfavorable prognosis in HCC-LT.

Fetal growth restriction (FGR) is a common complication of pregnancy and can have significant impact on obstetric and neonatal outcomes. Increasing evidence has shown that the inhibited mechanistic target of rapamycin (mTOR) signaling in placenta is associated with FGR. However, interpretation of existing research is limited due to inconsistent methodologies and varying understanding of the mechanism by which mTOR activity contributes to FGR. Hereby, we have demonstrated that different anatomic regions of human and mouse placentas exhibited different levels of mTOR activity in normal compared to FGR pregnancies. When using the rapamycin-induced FGR mouse model, we found that placentas of FGR pregnancies exhibited abnormal morphological changes and reduced mTOR activity in the decidual-junctional layer. Using transcriptomics and lipidomics, we revealed that lipid and energy metabolism was significantly disrupted in the placentas of FGR mice. Finally, we demonstrated that maternal physical exercise during gestation in our FGR mouse model was associated with increased fetal and placental weight as well as increased placental mTOR activity and lipid metabolism. Collectively, our data indicate that the inhibited placental mTOR signaling contributes to FGR with altered lipid metabolism in mouse placentas, and maternal exercise could be an effective method to reduce the occurrence of FGR or alleviate the adverse outcomes associated with FGR.

The development of the goat mammary gland is mainly under the control of ovarian hormones particularly estrogen and progesterone (P4). Amino acids play an essential role in mammary gland development and milk production, and sodium-coupled neutral amino acid transporter 2 (SNAT2) was reported to be expressed in the mammary gland of rats and bovine mammary epithelial cells, which may affect the synthesis of milk proteins or mammary cell proliferation by mediating prolactin, 17β-estradiol (E2) or methionine function. However, whether SNAT2 mediates the regulatory effects of E2 and P4 on the development of the ruminant mammary gland is still unclear. In this study, we show that E2 and P4 could increase the proliferation of goat mammary epithelial cells (GMECs) and regulate SNAT2 mRNA and protein expression in a dose-dependent manner. Further investigation revealed that SNAT2 is abundantly expressed in the mammary gland during late pregnancy and early lactation, while knockdown and overexpression of SNAT2 in GMECs could inhibit or enhance E2- and P4-induced cell proliferation as well as mammalian target of rapamycin (mTOR) signaling. We also found that the accelerated proliferation induced by SNAT2 overexpression in GMECs was suppressed by the mTOR signaling pathway inhibitor rapamycin. This indicates that the regulation of GMECs proliferation mediated by SNAT2 in response to E2 and P4 is dependent on the mTOR signaling pathway. Finally, we found that the total content of the amino acids in GMECs changed after knocking-down and overexpressing SNAT2. In summary, the results demonstrate that the regulatory effects of E2 and P4 on GMECs proliferation may be mediated by the SNAT2-transported amino acid pathway. These results may offer a novel nutritional target for improving the development of the ruminant mammary gland and milk production.

AXIN1, has been initially identified as a prominent antagonist within the WNT/β-catenin signaling pathway, and subsequently unveiled its integral involvement across a diverse spectrum of signaling cascades. These encompass the WNT/β-catenin, Hippo, TGFβ, AMPK, mTOR, MAPK, and antioxidant signaling pathways. The versatile engagement of AXIN1 underscores its pivotal role in the modulation of developmental biological signaling, maintenance of metabolic homeostasis, and coordination of cellular stress responses. The multifaceted functionalities of AXIN1 render it as a compelling candidate for targeted intervention in the realms of degenerative pathologies, systemic metabolic disorders, cancer therapeutics, and anti-aging strategies. This review provides an intricate exploration of the mechanisms governing mammalian AXIN1 gene expression and protein turnover since its initial discovery, while also elucidating its significance in the regulation of signaling pathways, tissue development, and carcinogenesis. Furthermore, we have introduced the innovative concept of the AXIN1-Associated Phosphokinase Complex (AAPC), where the scaffold protein AXIN1 assumes a pivotal role in orchestrating site-specific phosphorylation modifications through interactions with various phosphokinases and their respective substrates.

The evolutionarily conserved target of rapamycin (TOR) serine/threonine kinase controls eukaryotic cell growth, metabolism and survival by integrating signals from the nutritional status and growth factors. TOR is the catalytic subunit of two distinct functional multiprotein complexes termed mTORC1 (mechanistic target of rapamycin complex 1) and mTORC2, which phosphorylate a different set of substrates and display different physiological functions. Dysregulation of TOR signaling has been involved in the development and progression of several disease states including cancer and diabetes. Here, we highlight how genetic and biochemical studies in the model system Drosophila melanogaster have been crucial to identify the mTORC1 and mTORC2 signaling components and to dissect their function in cellular growth, in strict coordination with insulin signaling. In addition, we review new findings that involve Drosophila Golgi phosphoprotein 3 in regulating organ growth via Rheb-mediated activation of mTORC1 in line with an emerging role for the Golgi as a major hub for mTORC1 signaling.