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  1. Article ; Online: Regulatory roles of CARD9-BCL10-Rac1 (CBR) signalome in islet β-cell function in health and metabolic stress: Is there room for MALT1?

    Kowluru, Anjaneyulu

    Biochemical pharmacology

    2023  Volume 218, Page(s) 115889

    Abstract: It is widely accepted that pancreatic islet β-cell failure and the onset of type 2 diabetes (T2DM) constitute an intricate interplay between the genetic expression of the disease and a host of intracellular events including increased metabolic (oxidative, ...

    Abstract It is widely accepted that pancreatic islet β-cell failure and the onset of type 2 diabetes (T2DM) constitute an intricate interplay between the genetic expression of the disease and a host of intracellular events including increased metabolic (oxidative, endoplasmic reticulum) stress under the duress of glucolipotoxicity. Emerging evidence implicates unique roles for Caspase Recruitment Domain containing protein 9 (CARD9) in the onset of metabolic diseases, including obesity and insulin resistance. Mechanistically, CARD9 has been implicated in the regulation of p38MAPK and NFkB signaling pathways culminating in cellular dysfunction. Several regulatory factors, including B-cell lymphoma/leukemia 10 (BCL10) have been identified as modulators of CARD9 function in multiple cell types. Despite this evidence on regulatory roles of CARD9-BCL10 signalome in the onset of various pathological states, putative roles of this signaling module in islet β-cell dysfunction in metabolic stress remain less understood. This brief review is aimed at highlighting roles for CARD9 in islet β-cell function under acute (physiological insulin secretion) and long-term (cell dysfunction) exposure to glucose. Emerging roles of other signaling proteins, such as Rac1, BCL10 and MALT1 as contributors to CARD9 signaling in the islet β-cells are also reviewed. Potential avenues for future research toward the development of novel therapeutics for the prevention CARD9-BCL10-Rac1 (CBR) signalome-induced β-cell defects under metabolic stress are discussed.
    MeSH term(s) Humans ; B-Cell CLL-Lymphoma 10 Protein/genetics ; CARD Signaling Adaptor Proteins/genetics ; Diabetes Mellitus, Type 2 ; Islets of Langerhans ; Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein/genetics ; Proteins ; Signal Transduction ; Stress, Physiological
    Chemical Substances B-Cell CLL-Lymphoma 10 Protein ; BCL10 protein, human ; CARD Signaling Adaptor Proteins ; CARD9 protein, human ; MALT1 protein, human (EC 3.4.22.-) ; Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein (EC 3.4.22.-) ; Proteins ; RAC1 protein, human
    Language English
    Publishing date 2023-10-29
    Publishing country England
    Document type Journal Article ; Review ; Research Support, Non-U.S. Gov't
    ZDB-ID 208787-x
    ISSN 1873-2968 ; 0006-2952
    ISSN (online) 1873-2968
    ISSN 0006-2952
    DOI 10.1016/j.bcp.2023.115889
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  2. Article ; Online: Hyperglycemic Stress Induces Expression, Degradation, and Nuclear Association of Rho GDP Dissociation Inhibitor 2 (RhoGDIβ) in Pancreatic β-Cells.

    Gleason, Noah / Kowluru, Anjaneyulu

    Cells

    2024  Volume 13, Issue 3

    Abstract: Small G proteins (e.g., Rac1) play critical regulatory roles in islet β-cell function in health (physiological insulin secretion) and in metabolic stress (cell dysfunction and demise). Multiple regulatory factors for these G proteins, such as GDP ... ...

    Abstract Small G proteins (e.g., Rac1) play critical regulatory roles in islet β-cell function in health (physiological insulin secretion) and in metabolic stress (cell dysfunction and demise). Multiple regulatory factors for these G proteins, such as GDP dissociation inhibitors (GDIs), have been implicated in the functional regulation of these G proteins. The current set of investigations is aimed at understanding impact of chronic hyperglycemic stress on the expression and subcellular distribution of three known isoforms of RhoGDIs (RhoGDIα, RhoGDIβ, and RhoGDIγ) in insulin-secreting β-cells. The data accrued in these studies revealed that the expression of RhoGDIβ, but not RhoGDIα or RhoGDIγ, is increased in INS-1 832/13 cells, rat islets, and human islets. Hyperglycemic stress also promoted the cleavage of RhoGDIβ, leading to its translocation to the nuclear compartment. We also report that RhoGDIα, but not RhoGDIγ, is associated with the nuclear compartment. However, unlike RhoGDIβ, hyperglycemic conditions exerted no effects on RhoGDIα's association with nuclear fraction. Based on these observations, and our earlier findings of the translocation of Rac1 to the nuclear compartment under the duress of metabolic stress, we conclude that the RhoGDIβ-Rac1 signaling module promotes signals from the cytosolic to the nucleus, culminating in accelerated β-cell dysfunction under metabolic stress.
    MeSH term(s) Animals ; Humans ; Rats ; GTP-Binding Proteins/metabolism ; Insulin-Secreting Cells/metabolism ; rho Guanine Nucleotide Dissociation Inhibitor alpha/metabolism ; rho Guanine Nucleotide Dissociation Inhibitor beta/metabolism ; rho Guanine Nucleotide Dissociation Inhibitor gamma/metabolism
    Chemical Substances GTP-Binding Proteins (EC 3.6.1.-) ; rho Guanine Nucleotide Dissociation Inhibitor alpha ; rho Guanine Nucleotide Dissociation Inhibitor beta ; rho Guanine Nucleotide Dissociation Inhibitor gamma ; ARHGDIB protein, human
    Language English
    Publishing date 2024-02-01
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2661518-6
    ISSN 2073-4409 ; 2073-4409
    ISSN (online) 2073-4409
    ISSN 2073-4409
    DOI 10.3390/cells13030272
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Multiple Guanine Nucleotide Exchange Factors Mediate Glucose-Induced Rac1 Activation and Insulin Secretion: Is It Precise Regulatory Control or a Case of Two Peas from the Same Pod?

    Kowluru, Anjaneyulu

    ACS pharmacology & translational science

    2021  Volume 4, Issue 5, Page(s) 1702–1704

    Abstract: Glucose-stimulated insulin secretion involves G protein (Rac1)-mediated cytoskeletal remodeling and vesicular transport and fusion with the plasma membrane. Recent evidence implicates at least three guanine nucleotide exchange factors (GEFs), namely, ... ...

    Abstract Glucose-stimulated insulin secretion involves G protein (Rac1)-mediated cytoskeletal remodeling and vesicular transport and fusion with the plasma membrane. Recent evidence implicates at least three guanine nucleotide exchange factors (GEFs), namely, Tiam1, Vav2, and P-Rex1, in glucose-induced activation of Rac1 and insulin secretion. This Viewpoint highlights potential mechanisms underlying Tiam1/Vav2/P-Rex1 sensitive Rac1-mediated insulin secretion in the glucose-stimulated β-cell.
    Language English
    Publishing date 2021-08-27
    Publishing country United States
    Document type Journal Article
    ISSN 2575-9108
    ISSN (online) 2575-9108
    DOI 10.1021/acsptsci.1c00190
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Oxidative Stress in Cytokine-Induced Dysfunction of the Pancreatic Beta Cell: Known Knowns and Known Unknowns.

    Kowluru, Anjaneyulu

    Metabolites

    2020  Volume 10, Issue 12

    Abstract: Compelling evidence from earlier studies suggests that the pancreatic beta cell is inherently weak in its antioxidant defense mechanisms to face the burden of protecting itself against the increased intracellular oxidative stress following exposure to ... ...

    Abstract Compelling evidence from earlier studies suggests that the pancreatic beta cell is inherently weak in its antioxidant defense mechanisms to face the burden of protecting itself against the increased intracellular oxidative stress following exposure to proinflammatory cytokines. Recent evidence implicates novel roles for nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (Noxs) as contributors to the excessive intracellular oxidative stress and damage under metabolic stress conditions. This review highlights the existing evidence on the regulatory roles of at least three forms of Noxs, namely Nox1, Nox2, and Nox4, in the cascade of events leading to islet beta cell dysfunction, specifically under the duress of chronic exposure to cytokines. Potential crosstalk between key signaling pathways (e.g., inducible nitric oxide synthase [iNOS] and Noxs) in the generation and propagation of reactive molecules and metabolites leading to mitochondrial damage and cell apoptosis is discussed. Available data accrued in investigations involving small-molecule inhibitors and antioxidant protein expression methods as tools toward the prevention of cytokine-induced oxidative damage are reviewed. Lastly, current knowledge gaps in this field, and possible avenues for future research are highlighted.
    Language English
    Publishing date 2020-11-24
    Publishing country Switzerland
    Document type Journal Article ; Review
    ZDB-ID 2662251-8
    ISSN 2218-1989
    ISSN 2218-1989
    DOI 10.3390/metabo10120480
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: GPCRs, G Proteins, and Their Impact on β-cell Function.

    Kowluru, Anjaneyulu

    Comprehensive Physiology

    2020  Volume 10, Issue 2, Page(s) 453–490

    Abstract: Glucose-induced (physiological) insulin secretion from the islet β-cell involves interplay between cationic (i.e., changes in intracellular calcium) and metabolic (i.e., generation of hydrophobic and hydrophilic second messengers) events. A large body of ...

    Abstract Glucose-induced (physiological) insulin secretion from the islet β-cell involves interplay between cationic (i.e., changes in intracellular calcium) and metabolic (i.e., generation of hydrophobic and hydrophilic second messengers) events. A large body of evidence affirms support for novel regulation, by G proteins, of specific intracellular signaling events, including actin cytoskeletal remodeling, transport of insulin-containing granules to the plasma membrane for fusion, and secretion of insulin into the circulation. This article highlights the following aspects of GPCR-G protein biology of the islet. First, it overviews our current understanding of the identity of a wide variety of G protein regulators and their modulatory roles in GPCR-G protein-effector coupling, which is requisite for optimal β-cell function under physiological conditions. Second, it describes evidence in support of novel, noncanonical, GPCR-independent mechanisms of activation of G proteins in the islet. Third, it highlights the evidence indicating that abnormalities in G protein function lead to islet β-cell dysregulation and demise under the duress of metabolic stress and diabetes. Fourth, it summarizes observations of potential beneficial effects of GPCR agonists in preventing/halting metabolic defects in the islet β-cell under various pathological conditions (e.g., metabolic stress and inflammation). Lastly, it identifies knowledge gaps and potential avenues for future research in this evolving field of translational islet biology. Published 2020. Compr Physiol 10:453-490, 2020.
    MeSH term(s) Animals ; GTP-Binding Proteins/metabolism ; Humans ; Insulin Secretion ; Insulin-Secreting Cells/cytology ; Insulin-Secreting Cells/physiology ; Receptors, G-Protein-Coupled/metabolism
    Chemical Substances Receptors, G-Protein-Coupled ; GTP-Binding Proteins (EC 3.6.1.-)
    Language English
    Publishing date 2020-03-12
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. ; Review
    ISSN 2040-4603
    ISSN (online) 2040-4603
    DOI 10.1002/cphy.c190028
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Roles of GTP and Rho GTPases in pancreatic islet beta cell function and dysfunction.

    Kowluru, Anjaneyulu

    Small GTPases

    2020  Volume 12, Issue 5-6, Page(s) 323–335

    Abstract: A growing body of evidence implicates requisite roles for GTP and its binding proteins (Rho GTPases) in the cascade of events leading to physiological insulin secretion from the islet beta cell. Interestingly, chronic exposure of these cells to ... ...

    Abstract A growing body of evidence implicates requisite roles for GTP and its binding proteins (Rho GTPases) in the cascade of events leading to physiological insulin secretion from the islet beta cell. Interestingly, chronic exposure of these cells to hyperglycaemic conditions appears to result in sustained activation of specific Rho GTPases (e.g. Rac1) leading to significant alterations in cellular functions including defects in mitochondrial function and nuclear collapse culminating in beta cell demise. One of the objectives of this review is to highlight our current understanding of the regulatory roles of GTP and Rho GTPases in normal islet function (e.g. proliferation and insulin secretion) as well potential defects in these signalling molecules and metabolic pathways that could contribute islet beta cell dysfunction and loss of functional beta cell mass leading to the onset of diabetes. Potential knowledge gaps in this field and possible avenues for future research are also highlighted.
    MeSH term(s) Animals ; Guanosine Triphosphate/metabolism ; Humans ; Insulin-Secreting Cells/cytology ; Insulin-Secreting Cells/metabolism ; Islets of Langerhans/cytology ; Islets of Langerhans/metabolism ; Pancreatic Neoplasms/metabolism ; Pancreatic Neoplasms/pathology ; rho GTP-Binding Proteins/metabolism
    Chemical Substances Guanosine Triphosphate (86-01-1) ; rho GTP-Binding Proteins (EC 3.6.5.2)
    Language English
    Publishing date 2020-08-31
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. ; Review
    ZDB-ID 2682247-7
    ISSN 2154-1256 ; 2154-1248
    ISSN (online) 2154-1256
    ISSN 2154-1248
    DOI 10.1080/21541248.2020.1815508
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  7. Article ; Online: Potential roles of PP2A-Rac1 signaling axis in pancreatic β-cell dysfunction under metabolic stress: Progress and promise.

    Kowluru, Anjaneyulu

    Biochemical pharmacology

    2020  Volume 180, Page(s) 114138

    Abstract: Recent estimates by the International Diabetes Federation suggest that the incidence of diabetes soared to an all-time high of 463 million in 2019, and the federation predicts that by 2045 the number of individuals afflicted with this disease will ... ...

    Abstract Recent estimates by the International Diabetes Federation suggest that the incidence of diabetes soared to an all-time high of 463 million in 2019, and the federation predicts that by 2045 the number of individuals afflicted with this disease will increase to 700 million. Therefore, efforts to understand the pathophysiology of diabetes are critical for moving toward the development of novel therapeutic strategies for this disease. Several contributors (oxidative stress, endoplasmic reticulum stress and others) have been proposed for the onset of metabolic dysfunction and demise of the islet β-cell leading to the pathogenesis of diabetes. Existing experimental evidence revealed sustained activation of PP2A and Rac1 in pancreatic β-cells exposed to metabolic stress (diabetogenic) conditions. Evidence in a variety of cell types implicates modulatory roles for specific signaling proteins (α4, SET, nm23-H1, Pak1) in the functional regulation of PP2A and Rac1. In this Commentary, I overviewed potential cross-talk between PP2A and Rac1 signaling modules in the onset of metabolic dysregulation of the islet β-cell leading to impaired glucose-stimulated insulin secretion (GSIS), loss of β-cell mass and the onset of diabetes. Potential knowledge gaps and future directions in this fertile area of islet biology are also highlighted. It is hoped that this Commentary will provide a basis for future studies toward a better understanding of roles of PP2A-Rac1 signaling module in pancreatic β-cell dysfunction, and identification of therapeutic targets for the treatment of islet β-cell dysfunction in diabetes.
    MeSH term(s) Animals ; Cells, Cultured ; Diabetes Mellitus, Experimental/metabolism ; Glucose/pharmacology ; Humans ; Insulin/metabolism ; Insulin-Secreting Cells/drug effects ; Insulin-Secreting Cells/metabolism ; Oxidative Stress/drug effects ; Protein Phosphatase 2/metabolism ; Protein Processing, Post-Translational ; Receptor Cross-Talk ; Signal Transduction ; rac1 GTP-Binding Protein/metabolism
    Chemical Substances Insulin ; RAC1 protein, human ; Protein Phosphatase 2 (EC 3.1.3.16) ; rac1 GTP-Binding Protein (EC 3.6.5.2) ; Glucose (IY9XDZ35W2)
    Language English
    Publishing date 2020-07-04
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. ; Review
    ZDB-ID 208787-x
    ISSN 1873-2968 ; 0006-2952
    ISSN (online) 1873-2968
    ISSN 0006-2952
    DOI 10.1016/j.bcp.2020.114138
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  8. Article ; Online: Inappropriate movement of Rac1 contributes to glucotoxicity of the islet β-cell.

    Kowluru, Anjaneyulu

    Cell cycle (Georgetown, Tex.)

    2017  Volume 16, Issue 15, Page(s) 1387–1388

    MeSH term(s) Insulin-Secreting Cells ; Islets of Langerhans
    Language English
    Publishing date 2017-07-19
    Publishing country United States
    Document type Editorial ; Comment
    ZDB-ID 2146183-1
    ISSN 1551-4005 ; 1538-4101 ; 1554-8627
    ISSN (online) 1551-4005
    ISSN 1538-4101 ; 1554-8627
    DOI 10.1080/15384101.2017.1345229
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Regulatory Roles of Histone Deacetylation in Metabolic Stress-Induced Expression of Caspase Recruitment Domain-Containing Protein 9 (CARD9) in Pancreatic β-Cells.

    Hali, Mirabela / Pinto, Nelson / Gleason, Noah / Kowluru, Anjaneyulu

    International journal of molecular sciences

    2023  Volume 24, Issue 21

    Abstract: CARD9, a scaffolding protein, has been implicated in the pathogenesis of metabolic diseases, including obesity and diabetes. We recently reported novel roles for CARD9 in islet β-cell dysregulation under duress of gluco (HG)- and glucolipotoxic (GLT) ... ...

    Abstract CARD9, a scaffolding protein, has been implicated in the pathogenesis of metabolic diseases, including obesity and diabetes. We recently reported novel roles for CARD9 in islet β-cell dysregulation under duress of gluco (HG)- and glucolipotoxic (GLT) stress. CARD9 expression was also increased in β-cells following exposure to HG and GLT stress. The current study is aimed at understanding the putative roles of histone deacetylation in HG- and GLT-induced expression of CARD9. Using two structurally distinct inhibitors of histone deacetylases (HDACs), namely trichostatin (TSA) and suberoylanilide hydroxamic acid (SAHA), we provide the first evidence to suggest that the increased expression of CARD9 seen under duress of HG and GLT stress is under the regulatory control of histone deacetylation. Interestingly, the expression of protein kinase Cδ (PKCδ), a known upstream regulator of CARD9 activation, is also increased under conditions of metabolic stress. However, it is resistant to TSA and SAHA, suggesting that it is not regulated via histone deacetylation. Based on these data, we propose that targeting the appropriate HDACs, which mediate the expression (and function) of CARD9, might be the next step to further enhance our current understanding of the roles of CARD9 in islet dysfunction under metabolic stress and diabetes.
    MeSH term(s) Humans ; Histone Deacetylase Inhibitors/pharmacology ; Histones/metabolism ; Hydroxamic Acids/pharmacology ; Caspase Activation and Recruitment Domain ; Vorinostat ; Histone Deacetylases/genetics ; Histone Deacetylases/metabolism ; Stress, Physiological ; Diabetes Mellitus ; CARD Signaling Adaptor Proteins/metabolism
    Chemical Substances Histone Deacetylase Inhibitors ; Histones ; Hydroxamic Acids ; Vorinostat (58IFB293JI) ; Histone Deacetylases (EC 3.5.1.98) ; CARD9 protein, human ; CARD Signaling Adaptor Proteins
    Language English
    Publishing date 2023-11-06
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2019364-6
    ISSN 1422-0067 ; 1422-0067 ; 1661-6596
    ISSN (online) 1422-0067
    ISSN 1422-0067 ; 1661-6596
    DOI 10.3390/ijms242115994
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  10. Article ; Online: Novel regulatory roles of small G protein GDP dissociation stimulator (smgGDS) in insulin secretion from pancreatic β-cells.

    Gleason, Noah / Williams, Carol L / Kowluru, Anjaneyulu

    Molecular and cellular endocrinology

    2023  Volume 580, Page(s) 112104

    Abstract: Emerging evidence implicates novel roles for small G protein GDP dissociation stimulator (smgGDS) in G protein activation and subsequent targeting to relevant subcellular compartments for effector regulation. Given the well-established roles of small G ... ...

    Abstract Emerging evidence implicates novel roles for small G protein GDP dissociation stimulator (smgGDS) in G protein activation and subsequent targeting to relevant subcellular compartments for effector regulation. Given the well-established roles of small G proteins in insulin secretion, we undertook this investigation to determine the putative roles of smgGDS in insulin secretion. Immunoblotting studies revealed that both splice variants of smgGDS are expressed in human islets, rat islets and INS-1 832/13 cells. A significant inhibition (-52%) of glucose-stimulated insulin secretion (GSIS) was observed in INS-1 832/13 cells following siRNA-mediated depletion of smgGDS. In addition, insulin secretion elicited by a membrane depolarizing concentration of KCl (via increased calcium influx), forskolin (via increased cAMP generation) or IBMX (via inhibition of phosphodiesterase) was inhibited by -49%, -27%, and -28%, respectively. Subcellular distribution studies revealed no significant alterations in the abundance of smgGDS in the cytosolic and membrane fractions during the 45-min exposure of INS-1 832/13 cells to an insulinotropic concentration of glucose. Together, we present the first evidence of expression of smgGDS in human islets, rodent islets, and clonal β-cells. We also demonstrate novel regulatory roles of these proteins in insulin secretion derived from glucose metabolic events, including calcium- and cAMP-dependent signaling steps.
    MeSH term(s) Animals ; Humans ; Rats ; Calcium/metabolism ; Cell Line ; Glucose/pharmacology ; Glucose/metabolism ; Guanine Nucleotide Exchange Factors/metabolism ; Insulin/metabolism ; Insulin Secretion ; Insulin-Secreting Cells/metabolism ; Islets of Langerhans/metabolism ; Monomeric GTP-Binding Proteins
    Chemical Substances Calcium (SY7Q814VUP) ; Glucose (IY9XDZ35W2) ; Guanine Nucleotide Exchange Factors ; Insulin ; Monomeric GTP-Binding Proteins (EC 3.6.5.2) ; smgGDS protein, rat ; RAP1GDS1 protein, human
    Language English
    Publishing date 2023-10-30
    Publishing country Ireland
    Document type Journal Article
    ZDB-ID 187438-x
    ISSN 1872-8057 ; 0303-7207
    ISSN (online) 1872-8057
    ISSN 0303-7207
    DOI 10.1016/j.mce.2023.112104
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