Publications by authors named "Roman G Timoshchenko"

7 Publications

  • Page 1 of 1

Chemerin-activated functions of CMKLR1 are regulated by G protein-coupled receptor kinase 6 (GRK6) and β-arrestin 2 in inflammatory macrophages.

Mol Immunol 2019 02 18;106:12-21. Epub 2018 Dec 18.

Thurston Arthritis Research Center and the Department of Medicine, Division of Rheumatology, Allergy, and Immunology, University of North Carolina, Chapel Hill, NC 27599, United States; Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, United States. Electronic address:

Chemerin receptor (CMKLR1) is a G protein-coupled receptor (GPCR) implicated in macrophage-mediated inflammation and in several forms of human arthritis. Analogous to other GPCR, CMKLR1 is likely regulated by G protein-coupled receptor kinase (GRK) phosphorylation of intracellular domains in an activation-dependent manner, which leads to recruitment and termination of intracellular signaling via desensitization and internalization of the receptor. The ubiquitously expressed GRK family members include GRK2, GRK3, GRK5, and GRK6, but it is unknown which GRK regulates CMKLR1 cellular and signaling functions. Our data show that activation of CMKLR1 by chemerin in primary macrophages leads to signaling and functional outcomes that are regulated by GRK6 and β-arrestin 2. We show that arrestin recruitment to CMKLR1 following chemerin stimulation is enhanced with co-expression of GRK6. Further, internalization of endogenous CMKLR1, following the addition of chemerin, is decreased in inflammatory macrophages from GRK6- and β-arrestin 2-deficient mice. These GRK6- and β-arrestin 2-deficient macrophages display increased migration toward chemerin and altered AKT and Extracellular-signal Related Kinase (ERK) signaling. Our findings show that chemerin-activated CMKLR1 regulation in inflammatory macrophages is largely GRK6 and β-arrestin mediated, which may impact innate immunity and have therapeutic implications in rheumatic disease.
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http://dx.doi.org/10.1016/j.molimm.2018.12.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6584946PMC
February 2019

G Protein Coupled Receptor Kinase 3 Regulates Breast Cancer Migration, Invasion, and Metastasis.

PLoS One 2016 6;11(4):e0152856. Epub 2016 Apr 6.

Thurston Arthritis Research Center and the Department of Medicine, Division of Rheumatology, Allergy, and Immunology, University of North Carolina, Chapel Hill, NC 27599, United States of America.

Triple negative breast cancer (TNBC) is a heterogeneous disease that has a poor prognosis and limited treatment options. Chemokine receptor interactions are important modulators of breast cancer metastasis; however, it is now recognized that quantitative surface expression of one important chemokine receptor, CXCR4, may not directly correlate with metastasis and that its functional activity in breast cancer may better inform tumor pathogenicity. G protein coupled receptor kinase 3 (GRK3) is a negative regulator of CXCR4 activity, and we show that GRK expression correlates with tumorigenicity, molecular subtype, and metastatic potential in human tumor microarray analysis. Using established human breast cancer cell lines and an immunocompetent in vivo mouse model, we further demonstrate that alterations in GRK3 expression levels in tumor cells directly affect migration and invasion in vitro and the establishment of distant metastasis in vivo. The effects of GRK3 modulation appear to be specific to chemokine-mediated migration behaviors without influencing tumor cell proliferation or survival. These data demonstrate that GRK3 dysregulation may play an important part in TNBC metastasis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0152856PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4822790PMC
August 2016

Roles of chemokines CCL2 and CCL5 in the pharmacokinetics of PEGylated liposomal doxorubicin in vivo and in patients with recurrent epithelial ovarian cancer.

Nanomedicine 2015 Oct 17;11(7):1797-807. Epub 2015 Jun 17.

Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Carolina Center of Cancer Nanotechnology Excellence, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Center for Pharmacogenomics and Individualized Therapy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. Electronic address:

Unlabelled: Nanoparticles (NPs) are cleared by monocytes and macrophages. Chemokines CCL2 and CCL5 are key mediators for recruitment of these immune cells into tumors and tissues. The purpose of this study was to investigate effects of CCL2 and CCL5 on the pharmacokinetics (PKs) of NPs. Mice deficient in CCL2 or CCL5 demonstrated altered clearance and tissue distribution of polyethylene glycol tagged liposomal doxorubicin (PLD) compared to control mice. The PK studies using mice bearing SKOV3 ovarian cancer xenografts revealed that the presence of tumor cells and higher expression of chemokines were significantly associated with greater clearance of PLD compared to non-tumor bearing mice. Plasma exposure of encapsulated liposomal doxorubicin positively correlated with the total exposure of plasma CCL2 and CCL5 in patients with recurrent epithelial ovarian cancer treated with PLD. These data emphasize that the interplay between PLD and chemokines may have an important role in optimizing PLD therapy.

From The Clinical Editor: The use of nanoparticles as drug delivery carriers is gaining widespread acceptance in the clinical setting. However, the underlying pharmacokinetics of these novel drugs has not really been elucidated. In this interesting article, the authors carried out experiments using mice deficient in CCL2 or CCL5 to study the clearance of liposomal system. They showed the important role the immune system played and would enable better designs of future drug delivery systems.
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http://dx.doi.org/10.1016/j.nano.2015.05.007DOI Listing
October 2015

G protein-coupled receptor kinase-3-deficient mice exhibit WHIM syndrome features and attenuated inflammatory responses.

J Leukoc Biol 2013 Dec 9;94(6):1243-51. Epub 2013 Aug 9.

1.CB #7280, 3300 Manning Dr., Chapel Hill, NC 27599, USA.

Chemokine receptor interactions coordinate leukocyte migration in inflammation. Chemokine receptors are GPCRs that when activated, are phosphorylated by GRKs to turn off G protein-mediated signaling yet recruit additional signaling machinery. Recently, GRK3 was identified as a negative regulator of CXCL12/CXCR4 signaling that is defective in human WHIM syndrome. Here, we report that GRK3-/- mice exhibit numerous features of human WHIM, such as impaired CXCL12-mediated desensitization, enhanced CXCR4 signaling to ERK activation, altered granulocyte migration, and a mild myelokathexis. Moreover, GRK3-/- protects mice from two acute models of inflammatory arthritis (K/BxN serum transfer and CAIA). In these granulocyte-dependent disease models, protection of GRK3-/- mice is mediated by retention of cells in the marrow, fewer circulating granulocytes in the peripheral blood, and reduced granulocytes in the joints during active inflammation. In contrast to WHIM, GRK3-/- mice have minimal hypogammaglobulinemia and a peripheral leukocytosis with increased lymphocytes and absent neutropenia. Thus, we conclude that the loss of GRK3-mediated regulation of CXCL12/CXCR4 signaling contributes to some, but not all, of the complete WHIM phenotype and that GRK3 inhibition may be beneficial in the treatment of inflammatory arthritis.
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http://dx.doi.org/10.1189/jlb.0213097DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3828605PMC
December 2013

G-protein signaling modulator-3, a gene linked to autoimmune diseases, regulates monocyte function and its deficiency protects from inflammatory arthritis.

Mol Immunol 2013 Jun 29;54(2):193-8. Epub 2012 Dec 29.

Department of Pharmacology, UNC School of Medicine, Chapel Hill, NC 27599-7365, USA.

Polymorphism at the GPSM3 gene locus is inversely associated with four systemic autoimmune diseases, including rheumatoid arthritis and ankylosing spondylitis. G-protein signaling modulator-3 (GPSM3) expression is most pronounced in myeloid cells, in which it targets heterotrimeric G-protein Gαi subunits of chemokine receptors, critical to immune function. To begin to explore the regulatory role of GPSM3 in monocytes, human THP-1 and primary mouse myeloid cells were cultured under stimulus conditions; GPSM3 was found by immunoblotting to be expressed at highest levels in the mature monocyte. To evaluate the effects of GPSM3 deficiency on a myeloid-dependent autoimmune disease, collagen antibody-induced arthritis (CAIA) was induced in Gpsm3-/- and control mice, which were then analyzed for clinical score, paw swelling, intra-articular proinflammatory markers, and histopathology. Mice lacking GPSM3 were protected from CAIA, and expression of monocyte-representative pro-inflammatory chemokine receptors and cytokines in paws of Gpsm3-/- mice were decreased. Flow cytometry, apoptosis, and transwell chemotaxis experiments were conducted to further characterize the effect of GPSM3 deficiency on survival and chemokine responsiveness of monocytes. GPSM3-deficient myeloid cells had reduced migration ex vivo to CCL2, CX3CL1, and chemerin and enhanced apoptosis in vitro. Our results suggest that GPSM3 is an important regulator of monocyte function involving mechanisms of differentiation, survival, and chemotaxis, and deficiency in GPSM3 expression is protective in acute inflammatory arthritis.
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http://dx.doi.org/10.1016/j.molimm.2012.12.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3563835PMC
June 2013

Cellular targeting in autoimmunity.

Curr Allergy Asthma Rep 2012 Dec;12(6):495-510

Division of Rheumatology, Allergy, and Immunology and the Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC 27517, USA.

Many biologic agents that were first approved for the treatment of malignancies are now being actively investigated and used in a variety of autoimmune diseases such as rheumatoid arthritis (RA), antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, systemic lupus erythematosus (SLE), and Sjogren's syndrome. The relatively recent advance of selective immune targeting has significantly changed the management of autoimmune disorders and in part can be attributed to the progress made in understanding effector cell function and their signaling pathways. In this review, we will discuss the recent FDA-approved biologic therapies that directly target immune cells as well as the most promising investigational drugs affecting immune cell function and signaling for the treatment of autoimmune disease.
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http://dx.doi.org/10.1007/s11882-012-0307-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3493824PMC
December 2012

Decreased Th17 and antigen-specific humoral responses in CX₃ CR1-deficient mice in the collagen-induced arthritis model.

Arthritis Rheum 2012 May;64(5):1379-87

Department of Medicine, University of North Carolina at Chapel Hill, CB 7280, 3300 Manning Drive, Chapel Hill, NC 27599, USA.

Objective: CX(3) CR1 is a chemokine receptor that uniquely binds to its ligand fractalkine (CX(3) CL1) and has been shown to be important in inflammatory arthritis responses, largely due to its effects on cellular migration. This study was undertaken to test the hypothesis that genetic deficiency of CX(3) CR1 is protective in the chronic inflammatory arthritis model collagen-induced arthritis (CIA). Because CX(3) CR1 is expressed on T cells and antigen-presenting cells, we also examined adaptive immune functions in this model.

Methods: Autoantibody formation, clinical, histologic, T cell proliferative, and cytokine responses were evaluated in wild-type and CX(3) CR1-deficient DBA/1J mice after immunization with heterologous type II collagen (CII).

Results: CX(3) CR1(-/-) mice had an ∼30% reduction in arthritis severity compared to wild-type mice, as determined by 2 independent measures, paw swelling (P < 0.01) and clinical disease score (P < 0.0001). Additionally, compared to wild-type mice, CX(3) CR1(-/-) mice had an ∼50% decrease in anti-CII autoantibody formation (P < 0.05), decreased Th17 intraarticular cytokine expression (P < 0.01 for interleukin-17 [IL-17] and P < 0.001 for IL-23), and decreased total numbers of Th17 cells in inflamed joints (P < 0.05).

Conclusion: Our findings indicate that CX(3) CR1 deficiency is protective in inflammatory arthritis and may have effects that extend beyond migration that involve adaptive immune responses in autoimmune disease.
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http://dx.doi.org/10.1002/art.34320DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3238788PMC
May 2012