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Li C, Huang S, Peng J, Hong T, Zhou C, Tang J. 14-3-3ζ Mediates GABA AR Activation by Interacting with BIG1. Mol Neurobiol 2023; 60:1721-1732. [PMID: 36562883 DOI: 10.1007/s12035-022-03172-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 12/10/2022] [Indexed: 12/24/2022]
Abstract
Most fast synaptic inhibitions in the mammalian brain are mediated by GABAA receptors (GABAARs). An appropriate level of GABAAR expression at the cell surface is essential for neurodevelopment and the efficacy of GABAergic synaptic transmission. We previously reported that brefeldin A-inhibited GDP/GTP exchange factor 1 (BIG1), a binding partner of GABAARs, plays an important role in trafficking GABAARs to the cell surface. However, its regulatory mechanisms remain unknown. In the present study, we identified a new cellular protein, 14-3-3ζ, which can interact with the β subunit of GABAARs and BIG1 both in vitro and in vivo and colocalizes in the soma, dendrites, and axons of hippocampal neurons. Overexpression of 14-3-3ζ-WT increased the surface expression of BIG1 in dendrites and axons, as well as the binding of BIG1 with GABAAR. Depleted 14-3-3ζ with efficacious siRNA attenuated the interaction between BIG1 and GABAARs and resulted in significant decreases in the surface expression levels of BIG1 and GABAAR. GABAAR agonist treatment increased the expression levels of BIG1 and 14-3-3ζ on the surface, indicating that 14-3-3ζ is involved in regulating BIG1-mediated GABAAR surface expression. Depletion of BIG1 or 14-3-3ζ significantly decreased GABAAR expression at the cell surface and suppressed the GABA-gated influx of chloride ions. These data indicate that the combination of 14-3-3ζ and BIG1 is required for GABAAR membrane expression. Our results provide a potential promising therapeutic target for neurological disorders involving GABAergic synaptic transmission.
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Affiliation(s)
- Cuixian Li
- Experiment Teaching & Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Shen Huang
- Experiment Teaching & Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Jin Peng
- Laboratory of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510515, China
| | - Tianguo Hong
- Experiment Teaching & Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Chun Zhou
- Laboratory of Immunopharmacology, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, 510515, China.
- SMU-KI United Medical Inflammatory Center, School of Pharmaceutical Sciences; Guangdong Provincial Key Laboratory of Shock and Microcirculation, Southern Medical University, Guangzhou, 510515, China.
| | - Jie Tang
- Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, 510515, China.
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.
- Department of Otolaryngology Head & Neck Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, 510282, China.
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You Z, Yang Z, Cao S, Deng S, Chen Y. The novel KLF4/BIG1 regulates LPS-mediated neuro-inflammation and migration in BV2 cells via PI3K/Akt/NF-kB signaling pathway. Neuroscience 2022; 488:102-111. [DOI: 10.1016/j.neuroscience.2022.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/26/2021] [Accepted: 01/18/2022] [Indexed: 12/17/2022]
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Haploinsufficiency of ARFGEF1 is associated with developmental delay, intellectual disability, and epilepsy with variable expressivity. Genet Med 2021; 23:1901-1911. [PMID: 34113008 DOI: 10.1038/s41436-021-01218-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE ADP ribosylation factor guanine nucleotide exchange factors (ARFGEFs) are a family of proteins implicated in cellular trafficking between the Golgi apparatus and the plasma membrane through vesicle formation. Among them is ARFGEF1/BIG1, a protein involved in axon elongation, neurite development, and polarization processes. ARFGEF1 has been previously suggested as a candidate gene for different types of epilepsies, although its implication in human disease has not been well characterized. METHODS International data sharing, in silico predictions, and in vitro assays with minigene study, western blot analyses, and RNA sequencing. RESULTS We identified 13 individuals with heterozygous likely pathogenic variants in ARFGEF1. These individuals displayed congruent clinical features of developmental delay, behavioral problems, abnormal findings on brain magnetic resonance image (MRI), and epilepsy for almost half of them. While nearly half of the cohort carried de novo variants, at least 40% of variants were inherited from mildly affected parents who were clinically re-evaluated by reverse phenotyping. Our in silico predictions and in vitro assays support the contention that ARFGEF1-related conditions are caused by haploinsufficiency, and are transmitted in an autosomal dominant fashion with variable expressivity. CONCLUSION We provide evidence that loss-of-function variants in ARFGEF1 are implicated in sporadic and familial cases of developmental delay with or without epilepsy.
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BIG1 controls macrophage pro-inflammatory responses through ARF3-mediated PI(4,5)P2 synthesis. Cell Death Dis 2020; 11:374. [PMID: 32415087 PMCID: PMC7229175 DOI: 10.1038/s41419-020-2590-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/29/2020] [Indexed: 12/29/2022]
Abstract
Sepsis is caused by a dysregulated host inflammatory response to serious infections resulting in life-threatening organ dysfunction. The high morbidity and mortality make sepsis still a major clinical problem. Here, we investigated the roles of Brefeldin A-inhibited guanine nucleotide-exchange factor 1 (BIG1) in the pathogenesis process of sepsis and the underlying mechanisms. We found myeloid cell-specific BIG1 knockout (BIG1 cKO) significantly reduced the mortality and organ damage in LPS-induced and CLP-induced polymicrobial sepsis mouse model. The serum concentration and mRNA expression of pro-inflammatory cytokines including TNF-α, IL-6, IL-1β, and IL-12 were obviously decreased in BIG1 cKO mice. In bone marrow-derived macrophages or THP-1 cells, BIG1 deficiency caused an inhibited ARF3 activation, which reduced PI(4,5)P2 synthesis and the recruitment of TIRAP to the plasma membrane through inhibiting the activation of PIP5K induced by LPS, and eventually resulted in the inhibitory activity of TLR4-MyD88 signaling pathway. These results reveal a crucial new role of BIG1 in regulating macrophage inflammation responses, and provide evidence for BIG1 as a potential promising therapeutic target in sepsis.
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Teoh J, Subramanian N, Pero ME, Bartolini F, Amador A, Kanber A, Williams D, Petri S, Yang M, Allen AS, Beal J, Haut SR, Frankel WN. Arfgef1 haploinsufficiency in mice alters neuronal endosome composition and decreases membrane surface postsynaptic GABA A receptors. Neurobiol Dis 2019; 134:104632. [PMID: 31678406 DOI: 10.1016/j.nbd.2019.104632] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/23/2019] [Accepted: 10/01/2019] [Indexed: 12/23/2022] Open
Abstract
ARFGEF1 encodes a guanine exchange factor involved in intracellular vesicle trafficking, and is a candidate gene for childhood genetic epilepsies. To model ARFGEF1 haploinsufficiency observed in a recent Lennox Gastaut Syndrome patient, we studied a frameshift mutation (Arfgef1fs) in mice. Arfgef1fs/+ pups exhibit signs of developmental delay, and Arfgef1fs/+ adults have a significantly decreased threshold to induced seizures but do not experience spontaneous seizures. Histologically, the Arfgef1fs/+ brain exhibits a disruption in the apical lining of the dentate gyrus and altered spine morphology of deep layer neurons. In primary hippocampal neuron culture, dendritic surface and synaptic but not total GABAA receptors (GABAAR) are reduced in Arfgef1fs/+ neurons with an accompanying decrease in the number of GABAAR-containing recycling endosomes in cell body. Arfgef1fs/+ neurons also display differences in the relative ratio of Arf6+:Rab11+:TrfR+ recycling endosomes. Although the GABAAR-containing early endosomes in Arfgef1fs/+ neurons are comparable to wildtype, Arfgef1fs/+ neurons show an increase in the number of GABAAR-containing lysosomes in dendrite and cell body. Together, the altered endosome composition and decreased neuronal surface GABAAR results suggests a mechanism whereby impaired neuronal inhibition leads to seizure susceptibility.
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Affiliation(s)
- JiaJie Teoh
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States of America.
| | - Narayan Subramanian
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States of America
| | - Maria Elena Pero
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, United States of America; Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - Francesca Bartolini
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, United States of America
| | - Ariadna Amador
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States of America
| | - Ayla Kanber
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States of America
| | - Damian Williams
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States of America
| | - Sabrina Petri
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States of America
| | - Mu Yang
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States of America
| | - Andrew S Allen
- Department of Biostatistics and Bioinformatics, Duke University, Durham, NC, United States of America
| | - Jules Beal
- The Saul R. Korey Department of Neurology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY, United States of America
| | - Sheryl R Haut
- The Saul R. Korey Department of Neurology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY, United States of America
| | - Wayne N Frankel
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States of America; Department of Genetic and Development, Columbia University Irving Medical Center, New York, NY, United States of America
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Guo S, Xu N, Chen P, Liu Y, Qi X, Liu S, Li C, Tang J. Rapamycin Protects Spiral Ganglion Neurons from Gentamicin-Induced Degeneration In Vitro. J Assoc Res Otolaryngol 2019; 20:475-487. [PMID: 31236744 DOI: 10.1007/s10162-019-00717-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 03/12/2019] [Indexed: 02/06/2023] Open
Abstract
Gentamicin, one of the most widely used aminoglycoside antibiotics, is known to have toxic effects on the inner ear. Taken up by cochlear hair cells and spiral ganglion neurons (SGNs), gentamicin induces the accumulation of reactive oxygen species (ROS) and initiates apoptosis or programmed cell death, resulting in a permanent and irreversible hearing loss. Since the survival of SGNs is specially required for cochlear implant, new procedures that prevent SGN cell loss are crucial to the success of cochlear implantation. ROS modulates the activity of the mammalian target of rapamycin (mTOR) signaling pathway, which mediates apoptosis or autophagy in cells of different organs. However, whether mTOR signaling plays an essential role in the inner ear and whether it is involved in the ototoxic side effects of gentamicin remain unclear. In the present study, we found that gentamicin induced apoptosis and cell loss of SGNs in vivo and significantly decreased the density of SGN and outgrowth of neurites in cultured SGN explants. The phosphorylation levels of ribosomal S6 kinase and elongation factor 4E binding protein 1, two critical kinases in the mTOR complex 1 (mTORC1) signaling pathway, were modulated by gentamicin application in the cochlea. Meanwhile, rapamycin, a specific inhibitor of mTORC1, was co-applied with gentamicin to verify the role of mTOR signaling. We observed that the density of SGN and outgrowth of neurites were significantly increased by rapamycin treatment. Our finding suggests that mTORC1 is hyperactivated in the gentamicin-induced degeneration of SGNs, and rapamycin promoted SGN survival and outgrowth of neurites.
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Affiliation(s)
- Shasha Guo
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Nana Xu
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Peng Chen
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Ying Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xiaofei Qi
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Sheng Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Cuixian Li
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China. .,Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China. .,Institute of Mental Health, Southern Medical University, Guangzhou, China.
| | - Jie Tang
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China. .,Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China. .,Institute of Mental Health, Southern Medical University, Guangzhou, China.
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Abstract
The Golgi apparatus and its resident proteins are utilized and regulated by viruses to facilitate their proliferation. In this study, we investigated Classical swine fever virus (CSFV) proliferation when the function of the Golgi was disturbed. Golgi function was disturbed using chemical inhibitors, namely, brefeldin A (BFA) and golgicide A (GCA), and RNA interfering targets, such as the Golgi-specific BFA-resistance guanine nucleotide exchange factor 1 (GBF1) and Rab2 GTPases. CSFV proliferation was significantly inhibited during RNA replication and viral particle generation after BFA and GCA treatment. CSFV multiplication dynamics were retarded in cells transfected with GBF1 and Rab2 shRNA. Furthermore, CSFV proliferation was promoted by GBF1 and Rab2 overexpression using a lentiviral system. Hence, Golgi function is important for CSFV multiplication, and GBF1 and Rab2 participate in CSFV proliferation. Further studies must investigate Golgi-resident proteins to elucidate the mechanism underlying CSFV replication.
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Synchronized Progression of Prestin Expression and Auditory Brainstem Response during Postnatal Development in Rats. Neural Plast 2016; 2016:4545826. [PMID: 28097024 PMCID: PMC5210174 DOI: 10.1155/2016/4545826] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/08/2016] [Accepted: 11/30/2016] [Indexed: 12/23/2022] Open
Abstract
Prestin is the motor protein expressed in the cochlear outer hair cells (OHCs) of mammalian inner ear. The electromotility of OHCs driven by prestin is responsible for the cochlear amplification which is required for normal hearing in adult animals. Postnatal expression of prestin and activity of OHCs may contribute to the maturation of hearing in rodents. However, the temporal and spatial expression of prestin in cochlea during the development is not well characterized. In the present study, we examined the expression and function of prestin from the OHCs in apical, middle, and basal turns of the cochleae of postnatal rats. Prestin first appeared at postnatal day 6 (P6) for basal turn, P7 in middle turn, and P9 for apical turn of cochlea. The expression level increased progressively over the next few days and by P14 reached the mature level for all three segments. By comparison with the time course of the development of auditory brainstem response for different frequencies, our data reveal that prestin expression synchronized with the hearing development. The present study suggests that the onset time of hearing may require the expression of prestin and is determined by the mature function of OHCs.
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