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1.
Eur J Case Rep Intern Med ; 11(8): 004557, 2024.
Article in English | MEDLINE | ID: mdl-39130066

ABSTRACT

Takayasu arteritis (TA) primarily causes ischaemic nephrosclerosis but can occasionally be associated with glomerulopathy. We report a case of a female in her twenties with PLA2-negative, THSD7A-positive membranous nephropathy (MN) refractory to rituximab, who presented with neck pain and new-onset hypertension. Blood work showed elevated inflammatory markers. Imaging of the head and neck revealed focal dilation and irregularity of the vertebral arteries, consistent with TA. The patient was started on treatment with steroids, followed by mycophenolate mofetil, which led to the resolution of symptoms and nephrotic syndrome. This case highlights an uncommon sequence of events, with MN presenting before TA, underscoring the need to consider TA in differentials for patients with MN. Notably, this is the first reported case in a young female, emphasising the need for further understanding of TA-associated glomerular diseases. Additionally, the presence of THSD7A in MN, despite negative malignancy workup, is also noteworthy. LEARNING POINTS: Membranous nephropathy (MN) and Takayasu arteritis (TA) have distinct clinical presentations; therefore, diagnosing coexisting MN and TA is challenging, which may lead to delayed diagnoses.A multidisciplinary approach with tailored treatments is essential for prompt diagnosis and optimal management.Comprehensive follow-up studies are vital to understand the pathogenesis of this rare amalgamation, refine targeted treatment strategies and potentially improve overall prognosis.

2.
Mol Divers ; 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-39014147

ABSTRACT

Worldwide, cervical cancer (CCa) is a major killer of women. As the conventional drugs used to treat cervical cancer are expensive and expose severe side effects, there is a growing demand to search for novel modifications. Therefore, in the current investigation employing a bioinformatic approach, we explored triterpenoids for their anti-cancer efficacy by targeting cervical cancer epigenetic proteins, namely DNMT3A, HDAC4, and KMT2C. The study utilized molecular docking, ADMET assay, Molecular Dynamic simulation, and DFT calculation to unveil Betulin (BE) as the potential lead compound. Comparative analysis with that standard drug indicated that BE has a better glide score with the target protein KM2TC (- 9.893 kcal/mol), HDAC4 (- 9.720 kcal/mol), and DNMT3A (- 7.811 kcal/mol), which depicts that BE could be a potent inhibitor of these three epigenetic proteins and exhibits favorable pharmacokinetic, pharmacodynamics and toxicity properties. Molecular Dynamics simulation revealed noteworthy structural stability and compactness. DFT analysis revealed higher molecular activity of BE and showed the most increased kinetic stability (δE = 0.254647 eV). Further, we employed In vitro analysis through MTT assay and found that BE has IC50 of 15 µg/ml. In conclusion, BE can potentially treat CCa upon further investigations using in vivo models for better understanding.

3.
Adv Kidney Dis Health ; 31(3): 234-245, 2024 May.
Article in English | MEDLINE | ID: mdl-39004463

ABSTRACT

Lupus nephritis (LN) is a severe complication of systemic lupus erythematosus (SLE) and is one of the leading causes of morbidity and mortality in patients with SLE. It is estimated that up to 60% of individuals with SLE will develop LN, which can manifest at any stage of a patient's life; however, it commonly emerges early in the course of SLE and tends to exhibit a more aggressive phenotype in men compared to women. Black and Hispanic patients are more likely to progress to kidney failure than white patients. LN is characterized by kidney inflammation and chronic parenchymal damage, leading to impaired kidney function and potential progression to kidney failure. This article provides a comprehensive overview of the epidemiology, pathogenesis, clinical presentation, diagnosis, and management of LN, highlighting the importance of early recognition and treatment of LN to prevent progressive, irreversible kidney damage and improve patient outcomes. Additionally, the article discusses current and emerging therapies for LN, including traditional immunosuppressive agents, biological agents, and novel therapies targeting specific pathways involved in LN pathogenesis, to provide a practical guide for clinicians in properly diagnosing LN and determining a patient-centered treatment plan.


Subject(s)
Immunosuppressive Agents , Lupus Nephritis , Lupus Nephritis/diagnosis , Lupus Nephritis/therapy , Humans , Immunosuppressive Agents/therapeutic use , Disease Progression
4.
Macromolecules ; 57(10): 5119, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38827956

ABSTRACT

[This corrects the article DOI: 10.1021/acs.macromol.2c02475.].

5.
Mol Vis ; 30: 92-106, 2024.
Article in English | MEDLINE | ID: mdl-38601014

ABSTRACT

Exosomes are a subtype of extracellular vesicle (EV) that are released and found in almost all body fluids. Exosomes consist of and carry a variety of bioactive molecules, including genetic information in the form of microRNAs (miRNAs). miRNA, a type of small non-coding RNA, plays a key role in regulating genes by suppressing their translation. miRNAs are often disrupted in the pathophysiology of different conditions, including eye disease. The stability and easy detectability of exosomal miRNAs in body fluids make them promising biomarkers for the diagnosis of different diseases. Additionally, due to the natural delivery capabilities of exosomes, they can be modified to transport therapeutic miRNAs to specific recipient cells. Most exosome research has primarily focused on cancer, so there is limited research highlighting the importance of exosomes in ocular biology, particularly in cornea-associated pathologies. This review provides an overview of the existing evidence regarding the primary functions of exosomal miRNAs and their potential role in diagnostic and therapeutic applications in the human cornea.


Subject(s)
Corneal Diseases , Exosomes , MicroRNAs , Neoplasms , Humans , MicroRNAs/genetics , Biomarkers , Neoplasms/genetics , Neoplasms/pathology , Neoplasms/therapy , Exosomes/genetics , Exosomes/pathology , Corneal Diseases/diagnosis , Corneal Diseases/genetics , Corneal Diseases/therapy , Cornea/pathology
6.
Article in English | MEDLINE | ID: mdl-37700699

ABSTRACT

siRNA is an important tool for modulating gene expression in current biomedical research. It would be highly desirable for siRNA to respond to an external stimulus. In this paper, we report a convenient, photolabile caging agent to regulate siRNA functions. 2-bromo-4'-hydroxyacetophenone (BHAP) can readily modify phosphorothioate backbones and inhibit siRNAs. Mild UV irradiation will cleave the modifying moiety to generate natural nucleic acid backbones, thus activating siRNA functions. Such modification is conveniently conducted in an aqueous solution with high efficiency and is cost-effective and scalable. This approach provides a convenient tool for the controlled regulation of gene expression by deploying minimal usage of complex organic synthesis for site-specific installation of the caging group to siRNA unlike previous reported works that required a series of intricate organic synthesis and cumbersome purification techniques to achieve similar aims. This study will open new doors for optochemical regulation of a variety of genes by pHP caging group in mammalian cell culture.


Subject(s)
RNA, Double-Stranded , Ultraviolet Rays , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , RNA Interference
7.
J Biomol Struct Dyn ; : 1-13, 2023 Aug 24.
Article in English | MEDLINE | ID: mdl-37615411

ABSTRACT

Prostate cancer is the second most dangerous cancer type worldwide. While various treatment options are present i.e. agonists and antagonists, their utilization leads to adverse effects and due to this resistance developing, ultimately the outcome is remission. So, to overcome this issue, we have undertaken an in-silico investigation to identify promising and unique flavonoid candidates for combating prostate cancer. Using GOLD software, the study assessed the effectiveness of 560 natural secondary polyphenols against CDKN2. Protein Data Bank was used to retrieve the 3D crystal structure of CDKN2 (PDB Id: 4EK3) and we retrieved the structure of selected secondary polyphenols from the PubChem database. The compound Diosmetin shows the highest GOLD score with the selected Protein i.e. CDKN2 which is 58.72. To better understand the 2-dimensional and 3-dimensional interactions, the interacting amino acid residues were visualised using Discovery Studio 3.5 and Maestro 13.5. Using Schrodinger-Glide, the Diosmetin and CDKN2 were re-docked, and decoy ligands were docked to CDKN2, which was used to further ascertain the study. The ligands with the highest Gold score were forecasted for pharmacokinetics characteristics, and the results were tabulated and analysed. Utilising the Gromacs software and Desmond packages, 100 ns of Diosmetin molecular dynamics simulations were run to evaluate the structural persistence and variations of protein-ligand complexes. Additionally, our investigation revealed that Diosmetin had a better binding affinity with CDKN2 measuring 58.72, and it also showed remarkable stability across a 100-ns simulation. Thus, following in-vitro and in-vivo clinical studies, diosmetin might lead to the Prostate regimen.Communicated by Ramaswamy H. Sarma.

8.
Macromolecules ; 56(5): 1845-1854, 2023 Mar 14.
Article in English | MEDLINE | ID: mdl-36938512

ABSTRACT

The effect of composition and morphology on mechanochemical activation in nanostructured block copolymers was investigated in a series of poly(methyl methacrylate)-block-poly(n-butyl acrylate)-block-poly(methyl methacrylate) (PMMA-b-PnBA-b-PMMA) triblock copolymers containing a force-responsive spiropyran unit in the center of the rubbery PnBA midblock. Triblock copolymers with identical PnBA midblocks and varying lengths of PMMA end-blocks were synthesized from a spiropyran-containing macroinitiatior via atom transfer radical polymerization, yielding polymers with volume fractions of PMMA ranging from 0.21 to 0.50. Characterization by transmission electron microscopy revealed that the polymers self-assembled into spherical and cylindrical nanostructures. Simultaneous tensile tests and optical measurements revealed that mechanochemical activation is strongly correlated to the chemical composition and morphologies of the triblock copolymers. As the glassy (PMMA) block content is increased, the overall activation increases, and the onset of activation occurs at lower strain but higher stress, which agrees with predictions from our previous computational work. These results suggest that the self-assembly of nanostructured morphologies can play an important role in controlling mechanochemical activation in polymeric materials and provide insights into how polymer composition and morphology impact molecular-scale force distributions.

9.
Euroasian J Hepatogastroenterol ; 12(1): 31-34, 2022.
Article in English | MEDLINE | ID: mdl-35990869

ABSTRACT

Hydatid cyst is a zoonotic disease that most commonly occurs in liver and lungs. Here, we present five cases of hydatid cyst occurring in axillary subcutaneous region, adnexal region, ovary, gallbladder, and pancreas Echinococcusshould be considered in the differential diagnosis of any cystic lesions in any anatomic location, with or without viscera involvement particularly in endemic areas. How to cite this article: Sarngal S, Gandhi S, Arora S, et al. Unusual Presentation of Hydatid Cyst. Euroasian J Hepato-Gastroenterol 2022;12(1):31-34.

10.
Heliyon ; 8(5): e09403, 2022 May.
Article in English | MEDLINE | ID: mdl-35663739

ABSTRACT

Investigators were continuously creating novel nanotechnologies to address unmet requirements throughout the administration of therapeutic medicines & imaging agents for cancer treatment & diagnostics, appropriately. LNPs(Lipid nanoparticles) are legitimate particulates (approx. 100 nm in size) gathered from various lipid as well as other biochemical compounds which overall functionality to resolve biological barriers (biobarriers), allowing LNPs to selectively collect somewhere outside of disease-target cells again for responsive therapeutics. Most pharmaceutically important compounds were insoluble throughout water solutions, were chemical & physiologically unstable, or have toxicities. Among the most potential drug carrier for bioactive organic compounds is LBNPs (Lipid based nanoparticles) technologies. Its present use in chemotherapy have transformed treatment for cancer by increasing the antitumor effect of a number of chemotherapeutics. Because they may be created using naturally occurring sources, LBNPs have great temporal and thermal stability, maximum load potential, simplicity of preparations, cheap manufacturing costs, & big manufacturing output. Furthermore, combining chemotherapeutic drugs with LNPs reduces active therapeutic dosage and toxicities, lowers treatment resistance, & raises drug concentration in tumour cells while reducing concentrations in normal tissue. LBNPs were widely studied in cancer treatment, both in vitro and in vivo, with encouraging outcomes in certain clinical trials. This study provides an overview of the many types of LBNPs which have been created in latest years and their applications and contributions in different types of cancers.

11.
Arthritis Rheumatol ; 74(6): 915-926, 2022 06.
Article in English | MEDLINE | ID: mdl-35166048

ABSTRACT

Systemic lupus erythematosus affects the kidneys in ~50% of all patients, and lupus nephritis (LN) is the most common manifestation of kidney involvement. Despite prompt diagnosis and treatment with aggressive immunosuppression, a significant proportion of LN patients do not respond to treatment and are considered to have refractory LN. Several factors other than drug resistance, such as nonadherence to treatment, undertreatment with conventional drugs, the effects of accumulated chronic damage, and genetic factors, may contribute to a poor response to treatment and should be considered. We define refractory LN as no change in (or worsening of) proteinuria and/or estimated glomerular filtration rate in response to 2 different standard-of-care induction regimens after 4-6 months in patients who are adherent to treatment. For patients who have LN that is truly refractory to standard of care, B cell-targeted therapy, specifically rituximab (RTX), is the most common next step. There is limited evidence available on alternative rescue therapies that may be used when there is no response to RTX. These include anti-CD38, leflunomide, intravenous immunoglobulin, plasma exchange, autologous stem cell transplantation, chimeric antigen receptor T cell therapy, anticomplement therapy, and interleukin-2 therapy.


Subject(s)
Hematopoietic Stem Cell Transplantation , Lupus Erythematosus, Systemic , Lupus Nephritis , Humans , Rituximab/therapeutic use , Transplantation, Autologous
12.
J Neurosci ; 2021 Jun 07.
Article in English | MEDLINE | ID: mdl-34103363

ABSTRACT

Neuropeptide secretion from dense-core vesicles (DCVs) controls many brain functions. Several components of the DCV exocytosis machinery have recently been identified, but the participation of a SEC1/MUNC18 (SM) protein has remained elusive. Here, we tested the ability of the three exocytic SM proteins expressed in the mammalian brain, MUNC18-1/2/3, to support neuropeptide secretion. We quantified DCV exocytosis at a single vesicle resolution upon action potential train-stimulation in mouse CNS neurons (of unknown sex) using pHluorin- and/or mCherry-tagged Neuropeptide-Y (NPY) or Brain-Derived Neurotrophic Factor (BDNF). Conditional inactivation of Munc18-1 abolished all DCV exocytosis. Expression of MUNC18-1, but not MUNC18-2 or MUNC18-3, supported DCV exocytosis in Munc18-1 null neurons. Heterozygous (HZ) inactivation of Munc18-1, as a model for reduced MUNC18-1 expression, impaired DCV exocytosis, especially during the initial phase of train-stimulation, when the release was maximal. These data show that neurons critically and selectively depend on MUNC18-1 for neuropeptide secretion. Impaired neuropeptide secretion may explain aspects of the behavioral and neurodevelopmental phenotypes that were observed in Munc18-1 HZ mice.SIGNIFICANCE STATEMENT:Neuropeptide secretion from dense-core vesicles (DCVs) modulates synaptic transmission, sleep, appetite, cognition and mood. However, the mechanisms of DCV exocytosis are poorly characterized. Here, we identify MUNC18-1 as an essential component for neuropeptide secretion from DCVs. Paralogs MUNC18-2 or -3 cannot compensate for MUNC18-1. MUNC18-1 is the first protein identified to be essential for both neuropeptide secretion and synaptic transmission. In heterozygous Munc18-1 neurons, that have a 50% reduced MUNC18-1 expression and model the human STXBP1 syndrome, DCV exocytosis is impaired, especially during the initial phase of train-stimulation, when the release is maximal. These data show that MUNC18-1 is essential for neuropeptide secretion and that impaired neuropeptide secretion upon reduced MUNC18-1 expression may contribute to the symptoms of STXBP1 syndrome.

13.
Neuroepidemiology ; 55(3): 188-195, 2021.
Article in English | MEDLINE | ID: mdl-33951636

ABSTRACT

INTRODUCTION: In India, there have been only few published studies of Parkinson's disease (PD) showing a wide range of prevalence. We conducted this study to determine the prevalence of PD in the rural population of Gujarat, in the western region of India. METHODS: This cross-sectional descriptive study was conducted in the villages of Anand, a district of Gujarat, India, between September 2019 and February 2020. This study used a multistep approach including a screening questionnaire and video recording followed by clinical examination by a neurologist, laboratory evaluation, and brain imaging to evaluate patients with PD. RESULTS: A total population of 18,896 was screened. The overall crude prevalence of PD was 42.3 per 100,000, and the prevalence over the age of 60 was 308.9 per 100,000 which showed the trend of increasing disease prevalence with age. Their mean duration of illness was 39.3 ± 27.3 months, and more than half of patients with PD had multiple associated nonmotor symptoms and nearly one-third had comorbid anxiety or depression. Environmental factors are important in the pathogenesis of PD, but there was no clear association between patients with PD and certain variables including consumption of well water, exposure to pesticides or other toxins, smoking cigarettes, and drinking alcohol or coffee in our study. CONCLUSIONS: The present study showed the current epidemiological data of PD from Gujarat, in western India. Further studies across different regions in India need to be encouraged for better understanding of PD prevalence in the Indian population.


Subject(s)
Parkinson Disease , Cross-Sectional Studies , Humans , India/epidemiology , Parkinson Disease/epidemiology , Risk Factors , Rural Population
14.
Case Rep Rheumatol ; 2020: 8863858, 2020.
Article in English | MEDLINE | ID: mdl-33343961

ABSTRACT

Immunoglobulin A (IgA) vasculitis nephritis (IgAVN) and IgA nephropathy (IgAN) share many pathological parallels and are viewed as related diseases by many groups. Current treatment guidelines remain vague, controversial, and without consensus, especially regarding the role of immunosuppressive medications. We present five cases of IgAVN encountered at our tertiary care center between 2016 and 2020, which were treated with different immunosuppression regimens. Infection was the leading cause of death in this series. These cases provide evidence that IgAVN should be distinguished from IgAN on a spectrum of IgA-associated glomerulonephritis. The outcomes presented herein suggest that the morbidity and systematic involvement IgAVN is greater than previously believed and that these substantial risks should be reflected in contemporary treatment guidelines.

15.
Materials (Basel) ; 13(5)2020 Mar 01.
Article in English | MEDLINE | ID: mdl-32121528

ABSTRACT

A gateless lateral p-n junction with reconfigurability is demonstrated on graphene by ion-locking using solid polymer electrolytes. Ions in the electrolytes are used to configure electric-double-layers (EDLs) that induce p- and n-type regions in graphene. These EDLs are locked in place by two different electrolytes with distinct mechanisms: (1) a polyethylene oxide (PEO)-based electrolyte, PEO:CsClO4, is locked by thermal quenching (i.e., operating temperature < Tg (glass transition temperature)), and (2) a custom-synthesized, doubly-polymerizable ionic liquid (DPIL) is locked by thermally triggered polymerization that enables room temperature operation. Both approaches are gateless because only the source/drain terminals are required to create the junction, and both show two current minima in the backgated transfer measurements, which is a signature of a graphene p-n junction. The PEO:CsClO4 gated p-n junction is reconfigured to n-p by resetting the device at room temperature, reprogramming, and cooling to T < Tg. These results show an alternate approach to locking EDLs on 2D devices and suggest a path forward to reconfigurable, gateless lateral p-n junctions with potential applications in polymorphic logic circuits.

16.
J Obstet Gynaecol India ; 69(Suppl 2): 153-159, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31686749

ABSTRACT

BACKGROUND: Studies of prophylactic salpingo-oophorectomies in high-risk population led to incidental finding of precursor lesions in the fimbrial end of fallopian tube rather than the ovary. Early detection of these precursor lesions can be helpful in the prevention of ovarian tumors, and the presence of these lesions can be more efficiently studied by applying Sectioning and Extensively Examining the FIMbriated End (SEE-FIM) protocol. AIM: To study precursor lesions of fallopian tubes associated with ovarian tumors by applying SEE-FIM protocol. MATERIALS AND METHODS: Sixty specimens of hysterectomy with bilateral salpingo-oophorectomy, clinically diagnosed as ovarian tumor (study group), were examined by SEE-FIM protocol. Specimens without ovarian tumor were taken as the control group, and same protocol was applied on them. Histological changes in fallopian tube were grouped either as tubal intraepithelial carcinoma (TIC), tubal intraepithelial lesion (TIL), only stratification and negative for any changes. RESULTS: Out of 60 cases in the study group, 10.00% (6/60) cases showed TIC, 38.34% (23/60) cases revealed TIL, 23.33% (14/60) cases showed changes of stratification and the rest were negative for any changes. Among these 60 cases, there were 7 cases of high-grade serous carcinoma, 5 (71.43%) of them showed changes of TIC. In the control group, out of 60 cases, none showed TIC changes, TIL was noted in 6.66% (4/60) cases, changes of stratification were seen in 26.67% (16/60) cases and the rest were negative for any changes. CONCLUSION: SEE-FIM protocol maximizes the examination of fimbrial end and is helpful in identifying precursor lesions of ovarian epithelial tumors.

17.
World J Transplant ; 9(1): 1-13, 2019 Jan 16.
Article in English | MEDLINE | ID: mdl-30697516

ABSTRACT

Vaccine preventable diseases account for a significant proportion of morbidity and mortality in transplant recipients and cause adverse outcomes to the patient and allograft. Patients should be screened for vaccination history at the time of pre-transplant evaluation and vaccinated at least four weeks prior to transplantation. For non-immune patients, dead-vaccines can be administered starting at six months post-transplant. Live attenuated vaccines are contraindicated after transplant due to concern for infectious complications from the vaccine and every effort should be made to vaccinate prior to transplant. Since transplant recipients are on life-long immunosuppression, these patients may have lower rates of serological conversion, lower mean antibody titers and waning of protective immunity over shorter period as compared to general population. Recommendations regarding booster dose in kidney transplant recipients with sub-optimal serological response are lacking. Travel plans should be part of routine post-transplant assessment and pre-travel vaccines and counseling should be provided. More studies are needed on vaccination schedules, serological response, need for booster doses and safety of live attenuated vaccines in this special population.

18.
BMJ Case Rep ; 11(1)2018 Dec 07.
Article in English | MEDLINE | ID: mdl-30567197

ABSTRACT

Proliferative glomerulonephritis with monoclonal immune deposits (PGNMID) is a newly described entity characterised by monoclonal IgG deposits consisting of single light chain isotype and single heavy chain subtype (IgG1-4) in the kidneys. We are presenting two cases of patients who presented with acute kidney injury and worsening proteinuria. Kidney biopsy showed membranoproliferative pattern. Special staining for subclass of IgG showed monoclonal IgG3-kappa (case 1) and IgG1-kappa deposits (case 2) suggestive of PGNMID. Workup for underlying infection, malignancy, monoclonal gammopathy was negative. Since pathogenesis of PGNMID involves clonal proliferation of B-cells, we treated both patients with rituximab along with steroids that led to improvement of proteinuria and renal function. We also reviewed current literature to assess efficacy of rituximab in treatment of PGNMID. However, a larger pool of patients and a longer follow-up period is required to establish a role of rituximab and steroids in the treatment of this disease entity.


Subject(s)
Glomerulonephritis, Membranoproliferative/drug therapy , Glomerulonephritis, Membranoproliferative/immunology , Glucocorticoids/therapeutic use , Immunoglobulin G/metabolism , Immunologic Factors/therapeutic use , Immunosuppressive Agents/therapeutic use , Prednisone/therapeutic use , Rituximab/therapeutic use , Acute Kidney Injury/etiology , Adult , Diagnosis, Differential , Drug Therapy, Combination , Glomerulonephritis, Membranoproliferative/diagnosis , Humans , Male , Middle Aged , Proteinuria/etiology , Treatment Outcome
19.
EMBO J ; 37(20)2018 10 15.
Article in English | MEDLINE | ID: mdl-30185408

ABSTRACT

Neuropeptides are essential signaling molecules transported and secreted by dense-core vesicles (DCVs), but the number of DCVs available for secretion, their subcellular distribution, and release probability are unknown. Here, we quantified DCV pool sizes in three types of mammalian CNS neurons in vitro and in vivo Super-resolution and electron microscopy reveal a total pool of 1,400-18,000 DCVs, correlating with neurite length. Excitatory hippocampal and inhibitory striatal neurons in vitro have a similar DCV density, and thalamo-cortical axons in vivo have a slightly higher density. Synapses contain on average two to three DCVs, at the periphery of synaptic vesicle clusters. DCVs distribute equally in axons and dendrites, but the vast majority (80%) of DCV fusion events occur at axons. The release probability of DCVs is 1-6%, depending on the stimulation. Thus, mammalian CNS neurons contain a large pool of DCVs of which only a small fraction can fuse, preferentially at axons.


Subject(s)
Axons , Corpus Striatum , Hippocampus , Neurites , Secretory Vesicles , Synapses , Animals , Axons/metabolism , Axons/ultrastructure , Corpus Striatum/metabolism , Corpus Striatum/ultrastructure , Hippocampus/metabolism , Hippocampus/ultrastructure , Mice , Neurites/metabolism , Neurites/ultrastructure , Secretory Vesicles/metabolism , Secretory Vesicles/ultrastructure , Synapses/metabolism , Synapses/ultrastructure
20.
Mol Biol Cell ; 29(22): 2700-2708, 2018 11 01.
Article in English | MEDLINE | ID: mdl-30156474

ABSTRACT

Syntaxin (stx)-1 is an integral plasma membrane protein that is crucial for two distinct steps of regulated exocytosis, docking of secretory granules at the plasma membrane and membrane fusion. During docking, stx1 clusters at the granule docking site, together with the S/M protein munc18. Here we determined features of stx1 that contribute to its clustering at granules. In live insulin-secreting cells, stx1 and stx3 (but not stx4 or stx11) accumulated at docked granules, and stx1 (but not stx4) rescued docking in cells expressing botulinum neurotoxin-C. Using a series of stx1 deletion mutants and stx1/4 chimeras, we found that all four helical domains (Ha, Hb, Hc, SNARE) and the short N-terminal peptide contribute to recruitment to granules. However, only the Hc domain confers specificity, and it must be derived from stx1 for recruitment to occur. Point mutations in the Hc or the N-terminal peptide designed to interfere with binding to munc18-1 prevent stx1 from clustering at granules, and a mutant munc18 deficient in binding to stx1 does not cluster at granules. We conclude that stx1 is recruited to the docking site in a munc18-1-bound conformation, providing a rationale for the requirement for both proteins for granule docking.


Subject(s)
Munc18 Proteins/metabolism , Qa-SNARE Proteins/metabolism , Secretory Vesicles/metabolism , Animals , Cell Line , Exocytosis , Mice , Molecular Docking Simulation , Peptides/chemistry , Protein Binding , Protein Domains , Qa-SNARE Proteins/chemistry , Rats
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