SMEK1 ablation promotes glucose uptake and improves obesity-related metabolic dysfunction via AMPK signaling pathway.

OBJECTIVE: Obesity has become a major risk of global public health. SMEK1 is also known as a regulatory subunit of protein phosphatase 4 (PP4). Both PP4 and SMEK1 have been clarified many metabolic functions, including regulating the hepatic gluconeogenesis and glucose transporter gene expression in yeast. Whether SMEK1 participates in obesity and the broader metabolic role in mammals is unknown. Thus we investigated the function of SMEK1 in white adipose tissue and glucose uptake. METHODS: GWAS/GEPIA/GEO database was used to analyze the correlation between SMEK1 and metabolic phenotypes/lipid metabolism related genes/obesity. Smek1 KO mice were generated to identify the role of SMEK1 in obesity and glucose homeostasis. Cell culture and differentiation of SVFs and 3T3-L1 were used to determine the mechanism. 2-NBDG was used to measure the glucose uptake. Compound C was used to confirm the role of AMPK. RESULTS: We elucidated that SMEK1 was correlated to obesity and adipogenesis. Smek1 deletion enhanced adipogenesis in both SVFs and 3T3-L1. Smek1 KO protected mice from obesity, had protective effects on metabolic disorders including insulin resistance and inflammation. Smek1 KO mice have lower level of fasting serum glucose, we found that SMEK1 ablation promoted glucose uptake by increased p-AMPKα(T172) and the transcription of Glut4, when the effect on AMPK-regulated glucose uptake was due to the PP4 catalytic subunits (PPP4C). CONCLUSION: Our findings reveal a novel role of SMEK1 in obesity and glucose homeostasis, providing a potential new therapeutic target for obesity and metabolic dysfunction.

Role of LGL1 in cerebellar primordium of embryonic mice.

Lethal giant larvae 1 (LGL1) is originally recognized as a tumor suppressor, implicated in maintaining cell polarity in Drosophila and mammalian cells. Cell polarity plays a crucial role in tumorigenesis. We previously established Pax2-LGL1 -/- conditional knockout mice but did not focus on the tumorigenesis in cerebellar primordium. HE staining was used to detect the morphological structure of the cerebellar primordium during early embryonic development in Pax2-LGL1 -/- mice. Immunofluorescence assays were used to detect the expression of polar molecules. TUNEL staining assessed tissue apoptosis. Our findings reveal that deletion of LGL1 leads to the emergence of neuroblastoma-like tissues within the cerebellum primordium during early embryogenesis. This outcome can be attributed to alterations in expression patterns of polar molecules Cdc42 and ß-catenin following early deletion of LGL1, resulting in loss of cell polarity among neuroepithelial cells and subsequent formation of tumor-like tissues. However, further histological examination demonstrated that these tumor-like tissues disappear from embryonic day 15.5 onwards within the cerebellar primordium of Pax2-LGL1 -/- mice due to apoptosis-mediated cellular compensation. Our data emphasize the importance of LGL1 in maintaining neuroepithelial cell polarity and reveal a novel role for LGL1 in regulating tumorigenesis and ablation in the cerebellar primordium.

Astragaloside IV protects cardiomyocytes from hypoxic injury by regulating endoplasmic reticulum stress via eIF2α/CHOP signaling pathway.

Endoplasmic reticulum stress (ER stress) is suggested to promote cardiomyocyte apoptosis and ultimately lead to ischemic injury. Inhibition of ER stress-induced apoptosis may be a therapeutic strategy for MI injury. Astragaloside-IV (AST) from Astragalus membranaceus (Fisch) Bge, was reported to have cardioprotective properties. In this study, we investigated the protective effect of AST on cardiomyocytes against hypoxia injury by regulating ER stress and inhibiting apoptosis. H9c2 cardiomyocytes were divided into three groups, normal group, hypoxia group and AST group. Cell viability was determined by CCK-8 assay. Intracellular reactive oxygen species (ROS) production was detected by DCFH-DA (2,7- dichloro-dihydrofluorescein diacetate) florescent staining. The study showed that AST treatment could significantly increase the cell viability of H9c2 cells exposed to hypoxia. Furthermore, AST could restrain cell apoptosis and decrease the production of ROS. Compared with normal group, the protein levels of Bax, caspase-3, caspase-9, GRP78, p-eIF2α, and CHOP were enhanced in the hypoxia group, whereas the protein level of Bcl-2 was dramatically reduced. Compared with hypoxia group, AST markedly inhibited the phosphorylation of eIF2α and the expression of caspase-3, caspase-9 and CHOP, and promoted the protein expression of Bcl-2. Thus, AST can inhibit the ER stress-mediated apoptosis, partly through the eIF2α/CHOP pathway suppression to inhibit ER stress.

Loss of BAF (mSWI/SNF) chromatin-remodeling ATPase Brg1 causes multiple malformations of cortical development in mice.

Mutations in genes encoding subunits of the BAF (BRG1/BRM-associated factor) complex cause various neurodevelopmental diseases. However, the underlying pathophysiology remains largely unknown. Here, we analyzed the function of Brahma-related gene 1 (Brg1), a core ATPase of BAF complexes, in the developing cerebral cortex. Loss of Brg1 causes several morphological defects resembling human malformations of cortical developments (MCDs), including microcephaly, cortical dysplasia, cobblestone lissencephaly and periventricular heterotopia. We demonstrated that neural progenitor cell renewal, neuronal differentiation, neuronal migration, apoptotic cell death, pial basement membrane and apical junctional complexes, which are associated with MCD formation, were impaired after Brg1 deletion. Furthermore, transcriptome profiling indicated that a large number of genes were deregulated. The deregulated genes were closely related to MCD formation, and most of these genes were bound by Brg1. Cumulatively, our study indicates an essential role of Brg1 in cortical development and provides a new possible pathogenesis underlying Brg1-based BAF complex-related neurodevelopmental disorders.

Deficiency of Klc2 Induces Low-Frequency Sensorineural Hearing Loss in C57BL/6 J Mice and Human.

The transport system in cochlear hair cells (HCs) is important for their function, and the kinesin family of proteins transports numerous cellular cargos via the microtubule network in the cytoplasm. Here, we found that Klc2 (kinesin light chain 2), the light chain of kinesin-1 that mediates cargo binding and regulates kinesin-1 motility, is essential for cochlear function. We generated mice lacking Klc2, and they suffered from low-frequency hearing loss as early as 1 month of age. We demonstrated that deficiency of Klc2 resulted in abnormal transport of mitochondria and the down-regulation of the GABAA receptor family. In addition, whole-genome sequencing (WGS) of patient showed that KLC2 was related to low-frequency hearing in human. Hence, to explore therapeutic approaches, we developed adeno-associated virus containing the Klc2 wide-type cDNA sequence, and Klc2-null mice delivered virus showed apparent recovery, including decreased ABR threshold and reduced out hair cell (OHC) loss. In summary, we show that the kinesin transport system plays an indispensable and special role in cochlear HC function in mice and human and that mitochondrial localization is essential for HC survival.

Hongjingtian injection protects against myocardial ischemia reperfusion-induced apoptosis by blocking ROS induced autophagic- flux.

BACKGROUND: Hongjingtian injection (HJT) has been widely used in the clinic to treat coronary heart disease in China. However, the underlying mechanisms of therapies still need to be illustrated. The present study aims to determine whether HJT protects against myocardial ischemia reperfusion injury via Reactive Oxygen Species (ROS)-induced autophagic flux and apoptosis and, if so, to explore the underlying mechanisms. METHODS: In vivo myocardial protection and autophagy regulation of HJT in myocardial ischemia reperfusion injury in C57BL/6 J and CAG-RFP-EGFP-LC3 transgenic C57BL/6 J mice were investigated. In vitro, the effects of HJT on apoptosis, autophagic flux, oxidative stress and mitochondrial function were observed in H2O2-induced H9c2 cells. In addition, apoptosis-related proteins and autophagy-related proteins were assessed to explore the underlying mechanisms. RESULTS: HJT significantly decreased the infarct area and cell apoptosis after myocardial ischemia reperfusion injury in C57BL/6 J mice. Autophagic flux was reduced by HJT treatment after myocardial ischemia reperfusion injury in CAG-RFP-EGFP-LC3 transgenic C57BL/6 J mice. HJT inhibited H2O2-induced cell apoptosis by significantly decreasing the levels of cleaved caspase 3 and increasing the Bcl-2/Bax ratio. HJT inhibited autophagic flux after H2O2 stimulation by significantly decreasing LC3-Ⅱ and p-AMPK expression and increasing p-mTOR. HJT inhibited ROS production and improved mitochondrial function in H2O2-induced cells by significantly increasing the mitochondrial membrane potential, intracellular ATP contents and oxygen consumption. CONCLUSION: The beneficial effects of HJT in treating myocardial ischemia reperfusion are partially due to improved mitochondrial function and regulated autophagy to inhibit cell apoptosis through the AMPK/mTOR pathway.

Long Non-coding RNA TDRKH-AS1 Promotes Colorectal Cancer Cell Proliferation and Invasion Through the ß-Catenin Activated Wnt Signaling Pathway.

Colorectal cancer (CRC) is a common cancer worldwide, with a lower 5-years survival rate. Recently, long non-coding RNAs (lncRNAs) have been well-studied as the oncogenes or the tumor suppressors in multiple malignancies, including CRC. However, their biological functions and potential mechanisms in human cancer remain unclear. Here, we evaluated the expression of TDRKH-AS1 in CRC tissues and identified its potential targets. We found that TDRKH-AS1 is upregulated in majority of CRC patients, which is also significantly correlated with their malignant characteristics and their dismal prognoses. The high expression of TDRKH-AS1 can promote cancer cell proliferation substantially and invasion based on in vitro experiments. We also recognized that the TDRKH-AS1 targets the ß-catenin in the Wnt signaling pathway to exert its carcinogenic activity. TDRKH-AS1 could serve as a promising prognostic predictor and a potential therapeutic target for further early diagnoses and treatments via a non-invasive method.

Successful treatment of a huge hepatic carcinoma with right portal vein thrombosis: A case report.

INTRODUCTION: Unlike the traditional associating liver partition and portal vein ligation for staged hepatectomy, it is still controversial whether patients with portal vein thrombosis can receive benefits from liver partition. PATIENT CONCERNS: Right upper abdominal distension for 2 months. DIAGNOSIS: Hepatocellular carcinoma with portal vein invasion INTERVENTION:: Radiofrequency-assisted liver partition with portal vein ligation (RALPP) OUTCOMES:: Disease-free survival: 3 months, overall survival: 7 months CONCLUSION:: Our results advocate this variation of RALPP for use in patients with huge HCC with portal vein invasion, without enough future liver remnant. Patients can receive benefits from the operation, including a shorter operation time, better recovery, and lower overall costs of the 2-stage procedure.

Lianhua Qingwen prescription for Coronavirus disease 2019 (COVID-19) treatment: Advances and prospects.

BACKGROUND: An outbreak of Coronavirus Disease 2019 (COVID-19) which was infected by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is still spreading and has led to unprecedented health emergency over the world. Though no specific drug has been developed so far, emerging agents have been confirmed effective or potentially beneficial to restrain it. Lianhua Qingwen (LHQW) is a commonly used Chinese medical preparation to treat viral influenza, including in the fight against SARS in 2002-2003 in China. Recent data also showed that LHQW played a vigorous role in COVID-19 treatment. PURPOSE: This review will elucidate the pre-clinical and clinical evidence of LHQW in lung protection and antiviral activities, and provide timely data delivery for the exploration of effective treatment strategies in the therapy of COVID-19. STUDY DESIGN AND METHOD: The research data were obtained from the academic databases (up to August 8, 2020) including Pubmed, CNKI and Web of Science, on ethnobotany and ethno medicines. The search keywords for screening the literature information were "virus", "COVID-19", or "SARS-CoV-2", and "Lianhua Qingwen". The documents were filtered and summarized for final evaluation. RESULTS: The collected evidence demonstrated that LHQW exhibited benefits against COVID-19. Impressively, LHQW in conjunction with conventional treatment could significantly improve COVID-19 patients as a synergetic strategy. The mechanisms were mainly involved the antiviral activity, and regulation of inflammation response as well as immune function. CONCLUSION: Although the data were far from adequate, the latest advances had shown the benefits of LHQW in COVID-19, especially in combination with other antiviral drugs. This review provides comprehensive evidence of LHQW as a complementary strategy for treating COVID-19. Nevertheless, imperious researches should be conducted to clarify the unconfirmed effects, regulatory mechanisms and adverse reactions of LHQW in treating COVID-19 by means of well designed randomized controlled trials.

Deletion of Brg1 causes stereocilia bundle fusion and cuticular plate loss in vestibular hair cells.

Brg1 is an ATPase subunit of the SWI/SNF chromatin-remodeling complex, and it is indispensable for the development and homeostasis of various organs. Conditional deletion of Brg1 in cochlea hair cells (HCs) leads to multiple structural defects and profound deafness. However, the premature death of Brg1-deficient cochlea HCs hindered further study of the role of Brg1. In contrast to cochlea HCs, Brg1-deficient vestibular HCs survived for a long time. Therefore, HC apical structure and vestibular function were examined in inner HC-specific conditional Brg1 knockout mice. Vestibular HCs exhibited fused and elongated stereocilia bundles after deletion of Brg1, and the cuticular plate was absent in most HCs with fused stereocilia bundles. HC loss was observed in conditional Brg1 knockout mice at the age of 12 months. Morphological defects and HC loss were primarily restricted in the striolar region of the utricle and saccule and in the central region of ampulla. The behavioral tests revealed that Brg1 deletion in HCs caused vestibular dysfunction in older adult mice. These results suggest that Brg1 may play specific roles in the maintenance of the HC stereocilia bundle and the cuticular plate.

Tprn is essential for the integrity of stereociliary rootlet in cochlear hair cells in mice.

Tprn encodes the taperin protein, which is concentrated in the tapered region of hair cell stereocilia in the inner ear. In humans, TPRN mutations cause autosomal recessive nonsyndromic deafness (DFNB79) by an unknown mechanism. To determine the role of Tprn in hearing, we generated Tprn-null mice by clustered regularly interspaced short palindromic repeat/Cas9 genome-editing technology from a CBA/CaJ background. We observed significant hearing loss and progressive degeneration of stereocilia in the outer hair cells of Tprn-null mice starting from postnatal day 30. Transmission electron microscopy images of stereociliary bundles in the mutant mice showed some stereociliary rootlets with curved shafts. The central cores of the stereociliary rootlets possessed hollow structures with surrounding loose peripheral dense rings. Radixin, a protein expressed at stereocilia tapering, was abnormally dispersed along the stereocilia shafts in Tprn-null mice. The expression levels of radixin and ß-actin significantly decreased.We propose that Tprn is critical to the retention of the integrity of the stereociliary rootlet. Loss of Tprn in Tprn-null mice caused the disruption of the stereociliary rootlet, which resulted in damage to stereociliary bundles and hearing impairments. The generated Tprn-null mice are ideal models of human hereditary deafness DFNB79.

Beneficial Effects of Qingzixiaoban Granule on Henoch-Schönlein Purpura Nephritis Mice through Inhibiting Immune Complex Deposition and Th2 Immunodeviation.

BACKGROUND: Henoch-Schönlein purpura nephritis (HSPN) is the principal cause of morbidity and mortality in Henoch-Schönlein purpura (HSP). However, there is no absolute consensus for the best management of severe HSPN till now. Qingzixiaoban Granule (QZXB GR), a traditional Chinese medicine formula, has been applied to treat HSP in clinical in China. However, the therapeutic effects and potential mechanism of QZXB GR on HSPN is still unknown. METHODS: A Gliadin plus Indian Ink-induced HSPN mice model was established. Renal histopathologic changes and the subcutaneous hemorrhage on left legs were assessed. Hematuria and proteinuria were determined using hemocytometer and bicinchoninic acid assay, respectively. The serum circular immune complex and interleukin-6 were quantified by ELISA. Using blood biochemical analyzer, the renal biochemical parameters, including serum total protein, albumin, creatinine, and blood urea nitrogen, were measured. The deposition of immune complex in renal tissues and the lymphocyte subsets in peripheral blood and spleen was investigated by immunohistochemistry and flow cytometry. RESULTS: QZXB GR treatment significantly ameliorated renal injury in HSPN mice, by attenuating renal histopathological changes, reducing subcutaneous hemorrhage, decreasing proteinuria/hematuria, regulating renal biochemical parameters, and inhibiting the release of serum interleukin-6. Furthermore, QZXB GR treatment significantly decreased the level of serum circular immune complex, decreased immune complex IgA and IgG deposition in renal tissue, and suppressed Th2 immunodeviation. CONCLUSION: QZXB GR could prevent renal injury in HSPN mice, and its renoprotective mechanism might be exerted partly through suppressing immune complexes deposition and Th2 immune deviation.

Tuberous sclerosis complex-mediated mTORC1 overactivation promotes age-related hearing loss.

The underlying molecular mechanisms of age-related hearing loss (ARHL) in humans and many strains of mice have not been fully characterized. This common age-related disorder is assumed to be closely associated with oxidative stress. Here, we demonstrate that mTORC1 signaling is highly and specifically activated in the cochlear neurosensory epithelium (NSE) in aging mice, and rapamycin injection prevents ARHL. To further examine the specific role of mTORC1 signaling in ARHL, we generated murine models with NSE-specific deletions of Raptor or Tsc1, regulators of mTORC1 signaling. Raptor-cKO mice developed hearing loss considerably more slowly than WT littermates. Conversely, Tsc1 loss led to the early-onset death of cochlear hair cells and consequently accelerated hearing loss. Tsc1-cKO cochleae showed features of oxidative stress and impaired antioxidant defenses. Treatment with rapamycin and the antioxidant N-acetylcysteine rescued Tsc1-cKO hair cells from injury in vivo. In addition, we identified the peroxisome as the initial signaling organelle involved in the regulation of mTORC1 signaling in cochlear hair cells. In summary, our findings identify overactive mTORC1 signaling as one of the critical causes of ARHL and suggest that reduction of mTORC1 activity in cochlear hair cells may be a potential strategy to prevent ARHL.

Oocyte-specific deletion of Gsα induces oxidative stress and deteriorates oocyte quality in mice.

The stimulatory heterotrimeric Gs protein alpha subunit (Gsα) is a ubiquitous guanine nucleotide-binding protein that regulates the intracellular cAMP signaling pathway and consequently participates in a wide range of biological events. In the reproductive system, despite Gsα being associated with oocyte meiotic arrest in vitro, the exact role of Gsα in female fertility in vivo remains largely unknown. Here, we generated oocyte-specific Gsα knockout mice by using the Cre/LoxP system. We observed that the deletion of Gsα caused complete female infertility. Exclusion of post-implantation abnormalities, oogenesis, fertilization, and early embryo development was subsequently monitored; meiosis in Gsα-deficient oocytes precociously resumed in only 43% of antral follicles from mutant mice, indicating that alteration of meiotic pause was not the key factor in infertility. Ovulation process and number were normal, but the rate of morphological abnormal oocytes was apparently increased; spindle organization, fertilization, and early embryo development were impaired. Furthermore, the level of ROS (reactive oxygen species) and the mitochondrial aggregation increased, and antioxidant glutathione (GSH) content, ATP level, mtDNA copy number, and mitochondrial membrane potential decreased in Gsα-deficient oocytes. GV oocytes from mutant mice showed early-stage apoptosis. Meanwhile, the Gsα knockout-induced decline in oocyte quality and low developmental potential was partially rescued by antioxidant supplementation. To sum up, our results are the first to reveal that the profile of Gsα oocyte-specific deletion caused female infertility in vivo, and oxidative stress plays an important role in this event.

Rcan2 and estradiol independently regulate body weight in female mice.

Rcan2 increases food intake and plays an important role in the development of age- and diet- induced obesity in male mice. However, in females, wild-type mice grow almost at a similar rate as Rcan2-/- mice on normal chow diet from 6 weeks of age. Here we showed that the ability of Rcan2 to promote weight gain was attenuated by energy expenditure mediated by 17ß-estradiol in female mice. Using ovariectomy-operated models, we found that 17ß-estradiol deprivation did not alter food intake, but induced more weight gain in wild-type mice than Rcan2-/- mice. If wild-type mice ingested equally as Rcan2-/- mice, in the same ovarian state they exhibited similar weight changes, but the mice in ovariectomized groups were significantly heavier than the ovarian-intact mice, suggesting that body weight is not only regulated by Rcan2, but also by 17ß-estradiol. Furthermore, we demonstrated that Rcan2 and 17ß-estradiol independently regulated body weight even on high-fat diets. Therefore, our findings indicate that Rcan2 and 17ß-estradiol regulate body weight through different mechanisms. Rcan2 increases food intake, whereas 17ß-estradiol promotes energy expenditure. These findings provide novel insights into the sexual dimorphism of body weight regulation.

Loss of liver kinase B1 causes planar polarity defects in cochlear hair cells in mice.

The tumor suppressor gene liver kinase B1 (LKB1), also called STK11, encodes a serine/threonine kinase. LKB1 plays crucial roles in cell differentiation, proliferation, and polarity. In this study, LKB1 conditional knockout mice (LKB1Pax2 CKO mice) were generated using Pax2-Cre mice to investigate the function of LKB1 in inner ear hair cells during early embryonic period. LKB1Pax2 CKO mice died perinatally. Immunofluorescence and scanning electron microscopy revealed that stereociliary bundles in LKB1Pax2 CKO mice were clustered and misoriented, respectively. Moreover, ectopic distribution of kinocilium bundles resulting from abnormal migration of kinocilium was observed in the mutant mice. The orientation of stereociliary bundles and the migration of kinocilia are critical indicators of planar cell polarity (PCP) of hair cells. LKB1 deficiency in LKB1Pax2 CKO mice thus disrupted hair cell planar polarity during embryonic development. Our results suggest that LKB1 is required in PCP formation in cochlear hair cells in mice.

A disputed evidence on obesity: comparison of the effects of Rcan2(-/-) and Rps6kb1(-/-) mutations on growth and body weight in C57BL/6J mice.

It is widely accepted that body weight and adipose mass are tightly regulated by homeostatic mechanisms, in which leptin plays a critical role through hypothalamic pathways, and obesity is a result of homeostatic disorder. However, in C57BL/6J mice, we found that Rcan2 increases food intake and plays an important role in the development of age- and diet-induced obesity through a leptin-independent mechanism. RCAN2 was initially identified as a thyroid hormone (T3)-responsive gene in human fibroblasts. Expression of RCAN2 is regulated by T3 through the PI3K-Akt/PKB-mTOR-Rps6kb1 signaling pathway. Intriguingly, both Rcan2(-/-) and Rps6kb1(-/-) mutations were reported to result in lean phenotypes in mice. In this study we compared the effects of these two mutations on growth and body weight in C57BL/6J mice. We observed reduced body weight and lower fat mass in both Rcan2(-/-) and Rps6kb1(-/-) mice compared to the wild-type mice, and we reported other differences unique to either the Rcan2(-/-) or Rps6kb1(-/-) mice. Firstly, loss of Rcan2 does not directly alter body length; however, Rcan2(-/-) mice exhibit reduced food intake. In contrast, Rps6kb1(-/-) mice exhibit abnormal embryonic development, which leads to smaller body size and reduced food intake in adulthood. Secondly, when fed a normal chow diet, Rcan2(-/-) mice weigh significantly more than Rps6kb1(-/-) mice, but both Rcan2(-/-) and Rps6kb1(-/-) mice develop similar amounts of epididymal fat. On a high-fat diet, Rcan2(-/-) mice gain body weight and fat mass at slower rates than Rps6kb1(-/-) mice. Finally, using the double-knockout mice (Rcan2(-/-) Rps6kb1(-/-)), we demonstrate that concurrent loss of Rcan2 and Rps6kb1 has an additive effect on body weight reduction in C57BL/6J mice. Our data suggest that Rcan2 and Rps6kb1 mutations both affect growth and body weight of mice, though likely through different mechanisms.

Deletion of Brg1 causes abnormal hair cell planer polarity, hair cell anchorage, and scar formation in mouse cochlea.

Hair cells (HCs) are mechanosensors that play crucial roles in perceiving sound, acceleration, and fluid motion. The precise architecture of the auditory epithelium and its repair after HC loss is indispensable to the function of organ of Corti (OC). In this study, we showed that Brg1 was highly expressed in auditory HCs. Specific deletion of Brg1 in postnatal HCs resulted in rapid HC degeneration and profound deafness in mice. Further experiments showed that cell-intrinsic polarity of HCs was abolished, docking of outer hair cells (OHCs) by Deiter's cells (DCs) failed, and scar formation in the reticular lamina was deficient. We demonstrated that Brg1 ablation disrupted the Gαi/Insc/LGN and aPKC asymmetric distributions, without overt effects on the core planer cell polarity (PCP) pathway. We also demonstrated that Brg1-deficient HCs underwent apoptosis, and that leakage in the reticular lamina caused by deficient scar formation shifted the mode of OHC death from apoptosis to necrosis. Together, these data demonstrated a requirement for Brg1 activity in HC development and suggested a role for Brg1 in the proper cellular structure formation of HCs.

Loss of Myh14 Increases Susceptibility to Noise-Induced Hearing Loss in CBA/CaJ Mice.

MYH14 is a member of the myosin family, which has been implicated in many motile processes such as ion-channel gating, organelle translocation, and the cytoskeleton rearrangement. Mutations in MYH14 lead to a DFNA4-type hearing impairment. Further evidence also shows that MYH14 is a candidate noise-induced hearing loss (NIHL) susceptible gene. However, the specific roles of MYH14 in auditory function and NIHL are not fully understood. In the present study, we used CRISPR/Cas9 technology to establish a Myh14 knockout mice line in CBA/CaJ background (now referred to as Myh14-/- mice) and clarify the role of MYH14 in the cochlea and NIHL. We found that Myh14-/- mice did not exhibit significant hearing loss until five months of age. In addition, Myh14-/- mice were more vulnerable to high intensity noise compared to control mice. More significant outer hair cell loss was observed in Myh14-/- mice than in wild type controls after acoustic trauma. Our findings suggest that Myh14 may play a beneficial role in the protection of the cochlea after acoustic overstimulation in CBA/CaJ mice.

LKB1 Regulates Cerebellar Development by Controlling Sonic Hedgehog-mediated Granule Cell Precursor Proliferation and Granule Cell Migration.

The Liver Kinase B1 (LKB1) gene plays crucial roles in cell differentiation, proliferation and the establishment of cell polarity. We created LKB1 conditional knockout mice (LKB1(Atoh1) CKO) to investigate the function of LKB1 in cerebellar development. The LKB1(Atoh1) CKO mice displayed motor dysfunction. In the LKB1(Atoh1) CKO cerebellum, the overall structure had a larger volume and more lobules. LKB1 inactivation led to an increased proliferation of granule cell precursors (GCPs), aberrant granule cell migration and overproduction of unipolar brush cells. To investigate the mechanism underlying the abnormal foliation, we examined sonic hedgehog signalling (Shh) by testing its transcriptional mediators, the Gli proteins, which regulate the GCPs proliferation and cerebellar foliation during cerebellar development. The expression levels of Gli genes were significantly increased in the mutant cerebellum. In vitro assays showed that the proliferation of cultured GCPs from mutant cerebellum significantly increased, whereas the proliferation of mutant GCPs significantly decreased in the presence of a Shh inhibitor GDC-0049. Thus, LKB1 deficiency in the LKB1(Atoh1) CKO mice enhanced Shh signalling, leading to the excessive GCP proliferation and the formation of extra lobules. We proposed that LKB1 regulates cerebellar development by controlling GCPs proliferation through Shh signalling during cerebellar development.