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Adel SS, Clarke VRJ, Evans-Strong A, Maguire J, Paradis S. Semaphorin 4D induced inhibitory synaptogenesis decreases epileptiform activity and alters progression to Status Epilepticus in mice. Epilepsy Res 2023; 193:107156. [PMID: 37163910 PMCID: PMC10247425 DOI: 10.1016/j.eplepsyres.2023.107156] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 04/13/2023] [Accepted: 04/25/2023] [Indexed: 05/12/2023]
Abstract
Previously we demonstrated that intra-hippocampal infusion of purified, Semaphorin 4D (Sema4D) extracellular domain (ECD) into the mouse hippocampus rapidly promotes formation of GABAergic synapses and decreases seizure susceptibility in mice. Given the relatively fast action of Sema4D treatment revealed by these studies, we sought to determine the time course of Sema4D treatment on hippocampal network activity using an acute hippocampal slice preparation. We performed long-term extracellular recordings from area CA1 encompassing a 2-hour application of Sema4D and found that hippocampal excitation is suppressed for hours following treatment. We also asked if Sema4D treatment could ameliorate seizures in an acute seizure model: the kainic acid (KA) mouse model. We demonstrate that Sema4D treatment delays and suppresses ictal activity, delays the transition to Status Epilepticus (SE), and lessens the severity of SE. Lastly, we sought to explore alternative methods of Sema4D delivery to hippocampus and thus created an Adeno Associated Virus expressing the ECD of Sema4D. Our data reveal that virally delivered, chronically overexpressed Sema4D-ECD promotes GABAergic synapse formation and suppresses ictal activity and progression to SE. These results provide proof of concept that viral delivery of Sema4D is an efficacious and promising delivery method to abate epileptiform activity and progression to SE.
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Affiliation(s)
- Susannah S Adel
- Department of Biology and Volen Center for Complex Systems, Brandeis University, 415 South St., Waltham, MA 02453, USA
| | - Vernon R J Clarke
- Department of Biology and Volen Center for Complex Systems, Brandeis University, 415 South St., Waltham, MA 02453, USA.
| | - Aidan Evans-Strong
- Neuroscience Department, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, USA
| | - Jamie Maguire
- Neuroscience Department, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, USA
| | - Suzanne Paradis
- Department of Biology and Volen Center for Complex Systems, Brandeis University, 415 South St., Waltham, MA 02453, USA.
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2
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Madhavan SM, Konieczkowski M, Bruggeman LA, DeWalt M, Nguyen JK, O'Toole JF, Sedor JR. Essential role of Wtip in mouse development and maintenance of the glomerular filtration barrier. Am J Physiol Renal Physiol 2022; 323:F272-F287. [PMID: 35862649 PMCID: PMC9394782 DOI: 10.1152/ajprenal.00051.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 11/22/2022] Open
Abstract
Wilms' tumor interacting protein (Wtip) has been implicated in cell junction assembly and cell differentiation and interacts with proteins in the podocyte slit diaphragm, where it regulates podocyte phenotype. To define Wtip expression and function in the kidney, we created a Wtip-deleted mouse model using β-galactosidase-neomycin (β-geo) gene trap technology. Wtip gene trap mice were embryonic lethal, suggesting additional developmental roles outside kidney function. Using β-geo heterozygous and normal mice, Wtip expression was identified in the developing kidneys, heart, and eyes. In the kidney, expression was restricted to podocytes, which appeared initially at the capillary loop stage coinciding with terminal podocyte differentiation. Heterozygous mice had an expected lifespan and showed no evidence of proteinuria or glomerular pathology. However, heterozygous mice were more susceptible to glomerular injury than wild-type littermates and developed more significant and prolonged proteinuria in response to lipopolysaccharide or adriamycin. In normal human kidneys, WTIP expression patterns were consistent with observations in mice and were lost in glomeruli concurrent with loss of synaptopodin expression in disease. Mechanistically, we identified the Rho guanine nucleotide exchange factor 12 (ARHGEF12) as a binding partner for WTIP. ARHGEF12 was expressed in human podocytes and formed high-affinity interactions through their LIM- and PDZ-binding domains. Our findings suggest that Wtip is essential for early murine embryonic development and maintaining normal glomerular filtration barrier function, potentially regulating slit diaphragm and foot process function through Rho effector proteins.NEW & NOTEWORTHY This study characterized dynamic expression patterns of Wilms' tumor interacting protein (Wtip) and demonstrates the novel role of Wtip in murine development and maintenance of the glomerular filtration barrier.
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Affiliation(s)
- Sethu M Madhavan
- Department of Medicine, The Ohio State University, Columbus, Ohio
| | | | - Leslie A Bruggeman
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, Ohio
- Department of Nephrology, Cleveland Clinic, Cleveland, Ohio
| | - Megan DeWalt
- Department of Medicine, The Ohio State University, Columbus, Ohio
| | - Jane K Nguyen
- Department of Pathology, Cleveland Clinic, Cleveland, Ohio
| | - John F O'Toole
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, Ohio
- Department of Nephrology, Cleveland Clinic, Cleveland, Ohio
| | - John R Sedor
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, Ohio
- Department of Nephrology, Cleveland Clinic, Cleveland, Ohio
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
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3
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Hueting DA, Vanga SR, Syrén PO. Thermoadaptation in an Ancestral Diterpene Cyclase by Altered Loop Stability. J Phys Chem B 2022; 126:3809-3821. [PMID: 35583961 PMCID: PMC9169049 DOI: 10.1021/acs.jpcb.1c10605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Thermostability is
the key to maintain the structural integrity
and catalytic activity of enzymes in industrial biotechnological processes,
such as terpene cyclase-mediated generation of medicines, chiral synthons,
and fine chemicals. However, affording a large increase in the thermostability
of enzymes through site-directed protein engineering techniques can
constitute a challenge. In this paper, we used ancestral sequence
reconstruction to create a hyperstable variant of the ent-copalyl diphosphate synthase PtmT2, a terpene cyclase involved in
the assembly of antibiotics. Molecular dynamics simulations on the
μs timescale were performed to shed light on possible molecular
mechanisms contributing to activity at an elevated temperature and
the large 40 °C increase in melting temperature observed for
an ancestral variant of PtmT2. In silico analysis
revealed key differences in the flexibility of a loop capping the
active site, between extant and ancestral proteins. For the modern
enzyme, the loop collapses into the active site at elevated temperatures,
thus preventing biocatalysis, whereas the loop remains in a productive
conformation both at ambient and high temperatures in the ancestral
variant. Restoring a Pro loop residue introduced in the ancestral
variant to the corresponding Gly observed in the extant protein led
to reduced catalytic activity at high temperatures, with only moderate
effects on the melting temperature, supporting the importance of the
flexibility of the capping loop in thermoadaptation. Conversely, the
inverse Gly to Pro loop mutation in the modern enzyme resulted in
a 3-fold increase in the catalytic rate. Despite an overall decrease
in maximal activity of ancestor compared to wild type, its increased
thermostability provides a robust backbone amenable for further enzyme
engineering. Our work cements the importance of loops in enzyme catalysis
and provides a molecular mechanism contributing to thermoadaptation
in an ancestral enzyme.
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Affiliation(s)
- David A Hueting
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm 114 28, Sweden.,School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Stockholm 114 28, Sweden
| | - Sudarsana R Vanga
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm 114 28, Sweden.,School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Stockholm 114 28, Sweden
| | - Per-Olof Syrén
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm 114 28, Sweden.,School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Stockholm 114 28, Sweden
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4
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Christie SM, Hao J, Tracy E, Buck M, Yu JS, Smith AW. Interactions between semaphorins and plexin-neuropilin receptor complexes in the membranes of live cells. J Biol Chem 2021; 297:100965. [PMID: 34270956 PMCID: PMC8350011 DOI: 10.1016/j.jbc.2021.100965] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/30/2021] [Accepted: 07/12/2021] [Indexed: 11/27/2022] Open
Abstract
Signaling of semaphorin ligands via their plexin–neuropilin receptors is involved in tissue patterning in the developing embryo. These proteins play roles in cell migration and adhesion but are also important in disease etiology, including in cancer angiogenesis and metastasis. While some structures of the soluble domains of these receptors have been determined, the conformations of the full-length receptor complexes are just beginning to be elucidated, especially within the context of the plasma membrane. Pulsed-interleaved excitation fluorescence cross-correlation spectroscopy allows direct insight into the formation of protein–protein interactions in the membranes of live cells. Here, we investigated the homodimerization of neuropilin-1 (Nrp1), plexin A2, plexin A4, and plexin D1 using pulsed-interleaved excitation fluorescence cross-correlation spectroscopy. Consistent with previous studies, we found that Nrp1, plexin A2, and plexin A4 are present as dimers in the absence of exogenous ligand. Plexin D1, on the other hand, was monomeric under similar conditions, which had not been previously reported. We also found that plexin A2 and A4 assemble into a heteromeric complex. Stimulation with semaphorin 3A or semaphorin 3C neither disrupts nor enhances the dimerization of the receptors when expressed alone, suggesting that activation involves a conformational change rather than a shift in the monomer–dimer equilibrium. However, upon stimulation with semaphorin 3C, plexin D1 and Nrp1 form a heteromeric complex. This analysis of interactions provides a complementary approach to the existing structural and biochemical data that will aid in the development of new therapeutic strategies to target these receptors in cancer.
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Affiliation(s)
| | - Jing Hao
- Department of Cancer Biology, Cleveland Clinic, Cleveland, Ohio, USA
| | - Erin Tracy
- Department of Chemistry, University of Akron, Akron, Ohio, USA
| | - Matthias Buck
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Jennifer S Yu
- Department of Cancer Biology, Cleveland Clinic, Cleveland, Ohio, USA; Department of Radiation Oncology, Cleveland Clinic, Cleveland, Ohio, USA; Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, Ohio, USA
| | - Adam W Smith
- Department of Chemistry, University of Akron, Akron, Ohio, USA.
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Liu Y, Ke P, Kuo YC, Wang Y, Zhang X, Song C, Shan Y. A putative structural mechanism underlying the antithetic effect of homologous RND1 and RhoD GTPases in mammalian plexin regulation. eLife 2021; 10:64304. [PMID: 34114565 PMCID: PMC8219378 DOI: 10.7554/elife.64304] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 06/10/2021] [Indexed: 12/20/2022] Open
Abstract
Plexins are semaphorin receptors that play essential roles in mammalian neuronal axon guidance and in many other important mammalian biological processes. Plexin signaling depends on a semaphorin-induced dimerization mechanism and is modulated by small GTPases of the Rho family, of which RND1 serves as a plexin activator yet its close homolog RhoD an inhibitor. Using molecular dynamics (MD) simulations, we showed that RND1 reinforces the plexin dimerization interface, whereas RhoD destabilizes it due to their differential interaction with the cell membrane. Upon binding plexin at the Rho-GTPase-binding domain (RBD), RND1 and RhoD interact differently with the inner leaflet of the cell membrane and exert opposite effects on the dimerization interface via an allosteric network involving the RBD, RBD linkers, and a buttress segment adjacent to the dimerization interface. The differential membrane interaction is attributed to the fact that, unlike RND1, RhoD features a short C-terminal tail and a positively charged membrane interface.
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Affiliation(s)
- Yanyan Liu
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Pu Ke
- Beijing Computational Science Research Center, Beijing, China
| | - Yi-Chun Kuo
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Yuxiao Wang
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Xuewu Zhang
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Chen Song
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yibing Shan
- Antidote Health Foundation for Cure of Cancer, New York, United States
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