Imperial College London

DrBlerinaAhmetaj-Shala

Faculty of MedicineNational Heart & Lung Institute

Advanced Research Fellow
 
 
 
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Contact

 

+44 (0)20 7351 8137b.ahmetaj

 
 
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Location

 

Sir Alexander Fleming BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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51 results found

Vinokurova M, Lopes Pires M, Cypaite N, Shala F, Armstrong P, Ahmetaj-Shala B, Elghazouli Y, Nusing R, Liu B, Zhou Y, Hao C-M, Herschman H, Mitchell J, Kirkby Net al., 2024, Widening the prostacyclin paradigm: tissue fibroblasts are a critical site of production and anti-thrombotic protection, Arteriosclerosis, Thrombosis and Vascular Biology, Vol: 44, Pages: 271-286, ISSN: 1079-5642

BACKGROUND:Prostacyclin is a fundamental signaling pathway traditionally associated with the cardiovascular system and protection against thrombosis but which also has regulatory functions in fibrosis, proliferation, and immunity. Prevailing dogma states that prostacyclin is principally derived from vascular endothelium, although it is known that other cells can also synthesize it. However, the role of nonendothelial sources in prostacyclin production has not been systematically evaluated resulting in an underappreciation of their importance relative to better characterized endothelial sources.METHODS:To address this, we have used novel endothelial cell–specific and fibroblast-specific COX (cyclo-oxygenase) and prostacyclin synthase knockout mice and cells freshly isolated from mouse and human lung tissue. We have assessed prostacyclin release by immunoassay and thrombosis in vivo using an FeCl3-induced carotid artery injury model.RESULTS:We found that in arteries, endothelial cells are the main source of prostacyclin but that in the lung, and other tissues, prostacyclin production occurs largely independently of endothelial and vascular smooth muscle cells. Instead, in mouse and human lung, prostacyclin production was strongly associated with fibroblasts. By comparison, microvascular endothelial cells from the lung showed weak prostacyclin synthetic capacity compared with those isolated from large arteries. Prostacyclin derived from fibroblasts and other nonendothelial sources was seen to contribute to antithrombotic protection.CONCLUSIONS:These observations define a new paradigm in prostacyclin biology in which fibroblast/nonendothelial-derived prostacyclin works in parallel with endothelium-derived prostanoids to control thrombotic risk and potentially a broad range of other biology. Although generation of prostacyclin by fibroblasts has been shown previously, the scale and systemic activity was not tested and unappreciated. As such, this represents a basic

Journal article

George PM, Reed A, Desai SR, Devaraj A, Faiez TS, Laverty S, Kanwal A, Esneau C, Liu MKC, Kamal F, Man WD-C, Kaul S, Singh S, Lamb G, Faizi FK, Schuliga M, Read J, Burgoyne T, Pinto AL, Micallef J, Bauwens E, Candiracci J, Bougoussa M, Herzog M, Raman L, Ahmetaj-Shala B, Turville S, Aggarwal A, Farne HA, Dalla Pria A, Aswani AD, Patella F, Borek WE, Mitchell JA, Bartlett NW, Dokal A, Xu X-N, Kelleher P, Shah A, Singanayagam Aet al., 2022, A persistent neutrophil-associated immune signature characterizes post-COVID-19 pulmonary sequelae., Science Translational Medicine, Vol: 14, Pages: 1-16, ISSN: 1946-6234

Interstitial lung disease and associated fibrosis occur in a proportion of individuals who have recovered from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection through unknown mechanisms. We studied individuals with severe coronavirus disease 2019 (COVID-19) after recovery from acute illness. Individuals with evidence of interstitial lung changes at 3 to 6 months after recovery had an up-regulated neutrophil-associated immune signature including increased chemokines, proteases, and markers of neutrophil extracellular traps that were detectable in the blood. Similar pathways were enriched in the upper airway with a concomitant increase in antiviral type I interferon signaling. Interaction analysis of the peripheral phosphoproteome identified enriched kinases critical for neutrophil inflammatory pathways. Evaluation of these individuals at 12 months after recovery indicated that a subset of the individuals had not yet achieved full normalization of radiological and functional changes. These data provide insight into mechanisms driving development of pulmonary sequelae during and after COVID-19 and provide a rational basis for development of targeted approaches to prevent long-term complications.

Journal article

Pires ML, Vinokurova M, Shala F, Ahmetaj-Shala B, Armstrong PC, Herschman HR, Mitchell JA, Kirkby NSet al., 2022, Identifying Sources of Prostacyclin Outside the Vascular Wall and Their Contribution to Cardiovascular Protection, Scientific Sessions of the American-Heart-Association / Resuscitation Science Symposium, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322

Conference paper

Marei I, Ahmetaj-Shala B, Triggle CR, 2022, Biofunctionalization of cardiovascular stents to induce endothelialization: Implications for in- stent thrombosis in diabetes, FRONTIERS IN PHARMACOLOGY, Vol: 13

Journal article

Vaja R, Ferreira PM, Want L, Ahmetaj-Shala B, Gashaw H, Kirkby NS, Mitchell JAet al., 2022, SWATH proteomic analysis from the standard care versus celecoxib outcome trial identifies renal biomarkers are associated with early cardiovascular events amongst NSAID users, Publisher: OXFORD UNIV PRESS, Pages: 3045-3045, ISSN: 0195-668X

Conference paper

Vaja R, Atanur S, Mitchell JA, Ahmetaj-Shala Bet al., 2022, A Human atlas of smooth muscle cell gene expression; insights from the FANTOM consortium CAGE dataset, Publisher: OXFORD UNIV PRESS, Pages: 3022-3022, ISSN: 0195-668X

Conference paper

Latifi-Pupovci H, Namani S, Ahmetaj-Shala B, Pajaziti A, Bunjaku G, Ajazaj Berisha L, Gegaj V, Kotori Aet al., 2022, Biomarkers of Inflammation among Patients with COVID-19: A Single-Centre Prospective Study from Prishtina, Kosovo, CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY, Vol: 2022, ISSN: 1712-9532

Journal article

Latifi-Pupovci H, Namani S, Pajaziti A, Ahmetaj-Shala B, Ajazaj L, Kotori A, Haxhibeqiri V, Gegaj V, Bunjaku Get al., 2022, Relationship of anti-SARS-CoV-2 IgG antibodies with Vitamin D and inflammatory markers in COVID-19 patients, SCIENTIFIC REPORTS, Vol: 12, ISSN: 2045-2322

Journal article

Ferreira PM, Bayer S, Zhu D, Lim R, Ahmetaj-Shala B, Hind M, Griffiths M, Dean CH, Kim SYet al., 2022, Extracellular Vesicles in Lung Diseases, EXTRACELLULAR VESICLES, Editors: Chrzanowski, Lim, Kim, Publisher: ROYAL SOC CHEMISTRY, Pages: 216-245, ISBN: 978-1-78801-894-4

Book chapter

Ahmetaj-Shala B, Marei I, Kawai R, Rothery S, Pericleous C, Mohamed N, Gashaw H, Bokea K, Samuel J, Vandenheste A, Shala F, Kirkby N, Mitchell Jet al., 2021, Activation and contraction of human ‘vascular’ smooth muscle cells grown from circulating blood progenitors, Frontiers in Cell and Developmental Biology, Vol: 9, Pages: 1-6, ISSN: 2296-634X

Blood outgrowth smooth muscle cells offer the means to study vascular cells without the requirement for surgery providing opportunities for drug discovery, tissue engineering and personalised medicine. However, little is known about these cells which has meant their therapeutic potential remains unexplored. Our objective was to investigate for the first time the ability of blood outgrowth smooth muscle cells and vessel derived smooth muscle cells to sense the thromboxane mimetic U46619 bymeasuring intracellular calcium elevation and contraction. U46619 (10 26 -6M) increased cytosolic calcium in blood outgrowth smooth muscle cells fibroblasts. Increased calcium signal peaked between 10-20 seconds after U46619 in both smoothmuscle cell types. Importantly, U46619 (10-9 to 10-6M) induced concentration-dependent contractions of both blood outgrowth smooth muscle cells and vascular smooth muscle cells but not in fibroblasts. In summary, we show that functional responses of blood outgrowth smooth muscle cells are in line with vascular smooth muscle cells providing critical evidence of their application in biomedical research.

Journal article

Mohamed NA, Abou-Saleh H, Kameno Y, Marei I, de Nucci G, Ahmetaj-Shala B, Shala F, Kirkby NS, Jennings L, Al-Ansari DE, Davies RP, Lickiss PD, Mitchell JAet al., 2021, Studies on metal-organic framework (MOF) nanomedicine preparations of sildenafil for the future treatment of pulmonary arterial hypertension, Scientific Reports, Vol: 11, Pages: 1-8, ISSN: 2045-2322

Pulmonary arterial hypertension (PAH) is an incurable disease, although symptoms are treated with a range of dilator drugs. Despite their clinical benefits, these drugs are limited by systemic side-effects. It is, therefore, increasingly recognised that using controlled drug-release nanoformulation, with future modifications for targeted drug delivery, may overcome these limitations. This study presents the first evaluation of a promising nanoformulation (highly porous iron-based metal–organic framework (MOF); nanoMIL-89) as a carrier for the PAH-drug sildenafil, which we have previously shown to be relatively non-toxic in vitro and well-tolerated in vivo. In this study, nanoMIL-89 was prepared and charged with a payload of sildenafil (generating Sil@nanoMIL-89). Sildenafil release was measured by Enzyme-Linked Immunosorbent Assay (ELISA), and its effect on cell viability and dilator function in mouse aorta were assessed. Results showed that Sil@nanoMIL-89 released sildenafil over 6 h, followed by a more sustained release over 72 h. Sil@nanoMIL-89 showed no significant toxicity in human blood outgrowth endothelial cells for concentrations up to100µg/ml; however, it reduced the viability of the human pulmonary artery smooth muscle cells (HPASMCs) at concentrations > 3 µg/ml without inducing cellular cytotoxicity. Finally, Sil@nanoMIL-89 induced vasodilation of mouse aorta after a lag phase of 2–4 h. To our knowledge, this study represents the first demonstration of a novel nanoformulation displaying delayed drug release corresponding to vasodilator activity. Further pharmacological assessment of our nanoformulation, including in PAH models, is required and constitutes the subject of ongoing investigations.

Journal article

Mitchell JA, Kirkby NS, Ahmetaj-Shala B, Armstrong P, Crescente M, Ferreira P, Pires MEL, Vaja RK, Warner TDet al., 2021, Cyclooxygenases and the cardiovascular system, Pharmacology and Therapeutics, Vol: 217, Pages: 1-11, ISSN: 0163-7258

Cyclooxygenase (COX)-1 and COX-2 are centrally important enzymes within the cardiovascular system with a range of diverse, sometimes opposing, functions. Through the production of thromboxane, COX in platelets is a pro-thrombotic enzyme. By contrast, through the production of prostacyclin, COX in endothelial cells is antithrombotic and in the kidney regulates renal function and blood pressure. Drug inhibition of COX within the cardiovascular system is important for both therapeutic intervention with low dose aspirin and for the manifestation of side effects caused by nonsteroidal anti-inflammatory drugs. This review focuses on the role that COX enzymes and drugs that act on COX pathways have within the cardiovascular system and provides an in-depth resource covering COX biology and pharmacology. The review goes on to consider the role of COX in both discrete cardiovascular locations and in associated organs that contribute to cardiovascular health. We discuss the importance of, and strategies to manipulate, the thromboxane: prostacyclin balance. Finally within this review the authors discuss testable COX-2-hypotheses intended to stimulate debate and facilitate future research and therapeutic opportunities within the field.

Journal article

Ahmetaj-Shala B, Peacock TP, Baillon L, Swann OC, Gashaw H, Barclay WS, Mitchell JAet al., 2020, Resistance of endothelial cells to SARS-CoV-2 infection <i>in vitro</i>

<jats:title>Abstract</jats:title><jats:sec><jats:title>Rationale</jats:title><jats:p>The secondary thrombotic/vascular clinical syndrome of COVID-19 suggests that SARS-CoV-2 infects not only respiratory epithelium but also the endothelium activating thrombotic pathways, disrupting barrier function and allowing access of the virus to other organs of the body. However, a direct test of susceptibility to SARS-CoV-2 of authentic endothelial cell lines has not been performed.</jats:p></jats:sec><jats:sec><jats:title>Objective</jats:title><jats:p>To determine infectibility of primary endothelial cell lines with live SARS-CoV-2 and pseudoviruses expressing SARS-CoV-2 spike protein.</jats:p></jats:sec><jats:sec><jats:title>Methods and Results</jats:title><jats:p>Expression of ACE2 and BSG pathways genes was determined in three types of endothelial cells; blood outgrowth, lung microvascular and aortic endothelial cells. For comparison nasal epithelial cells, Vero E6 cells (primate kidney fibroblast cell line) and HEK 293T cells (human embryonic kidney cells) transfected with either ACE2 or BSG were used as controls. Endothelial and Vero E6 cells were treated with live SARS-CoV-2 virus for 1 hour and imaged at 24 and 72 hours post infection. Pseudoviruses containing SARS-CoV-2, Ebola and Vesicular Stomatis Virus glycoproteins were generated and added to endothelial cells and HEK 239Ts for 2 hours and infection measured using luminescence at 48 hours post infection. Compared to nasal epithelial cells, endothelial cells expressed low or undetectable levels of ACE2 and TMPRSS2 but comparable levels of BSG, PPIA and PPIB. Endothelial cells showed no susceptibility to live SARS-CoV-2 or SARS-CoV-2 pseudovirus (but showed susceptibility to Ebola and Vesicular Stomatitis Virus). Overexpression of ACE2 but not BSG in HEK 239T cells conferred SARS-CoV-2 pseudovirus entry. Endoth

Journal article

Ahmetaj-Shala B, Ricky V, Santosh A, Peter G, Nicholas K, Jane Met al., 2020, Cardiorenal tissues express SARS-CoV-2 entry genes and basigin (BSG/CD147) increases with age in endothelial cells, JACC: Basic to Translational Science, Vol: 5, Pages: 1111-1123, ISSN: 2452-302X

Objectives: To obtain mechanistic insight into COVID-19 within a cardiovascular setting.Background: Thrombosis and vascular dysfunction are part of the complex pathology seen in severe COVID-19 and advancing age is the most significant risk factor. Little is known about age and expression of pathways utilised by the COVID-19 virus, SARS-CoV-2, in cardiovascular tissues.Methods: We used publicly available databases (GTEx, GEO and Array Express) to investigate gene expression levels, in adult tissues, of the two putative SARS-CoV-2 receptors, ACE2 and BSG along with a selected range of genes thought to be involved in virus binding/processing. Our analysis included; vessels (aorta and coronary artery), heart (atrial appendage and left ventricle), kidney (cortex), whole blood, lung, colon and spleen along with endothelial cells, nasal and bronchial epithelium and peripheral blood mononuclear cells. Gene expression levels were then analysed for age associations.Results: We found: (i) cardiovascular tissues/endothelial cells express the required genes for SARS-CoV-2 infection, (ii) SARS-CoV-2 receptor pathways, ACE2/TMPRSS2 and BSG/PPIB(A) polarise to lung/epithelium and vessel/endothelium respectively, (iii) expression of host genes are relatively stable with age and (iv) notable exceptions are ACE2 which decreases with age in some tissues and BSG which increases with age in endothelial cells.Conclusion: Our data identifies a positive correlation of BSG with age in endothelial cells. Since BSG is utilised by other pathogens and is implicated in a range of cardiovascular disease, our observations may have relevance to our understanding of mechanisms associated with other pathogens and in the diseases associated with aging respectively.

Journal article

Kirkby N, Raouf J, Ahmetaj-Shala B, Liu B, Mazi S, Edin M, Geoffrey Chambers M, Korotkova M, Wang X, Wahli W, Zeldin D, Nusing R, Zhou Y, Jakobsson P-J, Mitchell Jet al., 2020, Mechanistic definition of the cardiovascular mPGES-1/COX-2/ADMA axis, Cardiovascular Research, Vol: 116, Pages: 1972-1980, ISSN: 0008-6363

Aims:Cardiovascular side effects caused by non-steroidal anti-inflammatory drugs (NSAIDs), which all inhibit cyclooxygenase (COX)-2, have prevented development of new drugs that target prostaglandins to treat inflammation and cancer. Microsomal prostaglandin E synthase-1 (mPGES-1) inhibitors have efficacy in the NSAID arena but their cardiovascular safety is not known. Our previous work identified asymmetric dimethylarginine (ADMA), an inhibitor of eNOS, as a potential biomarker of cardiovascular toxicity associated with blockade of COX-2. Here we have used pharmacological tools and genetically modified mice to delineate mPGES-1 and COX-2 in the regulation of ADMA.Methods and Results:Inhibition of COX-2 but not mPGES-1 deletion resulted in increased plasma ADMA levels. mPGES-1 deletion but not COX-2 inhibition resulted in increased plasma prostacyclin levels. These differences were explained by distinct compartmentalisation of COX-2 and mPGES-1 in the kidney. Data from prostanoid synthase/receptor knockout mice showed that the COX-2/ADMA axis is controlled by prostacyclin receptors (IP and PPARβ/δ) and the inhibitory PGE2 receptor EP4, but not other PGE2 receptors.Conclusions:These data demonstrate that inhibition of mPGES-1 spares the renal COX-2/ADMA pathway and define mechanistically how COX-2 regulates ADMA.

Journal article

Kirkby N, Gashaw H, Perikleous A, Ferreira P, Ahmetaj-Shala B, Mitchell Jet al., 2020, Novel arginine formulations of celecoxib fully retain COX-2 inhibitory and anti-cancer activity and reverse L-NAME-induced endothelial dysfunction, Meeting of the British-Pharmacological-Society, Publisher: WILEY, Pages: 2491-2492, ISSN: 0007-1188

Conference paper

Mohamed N, Abou Saleh H, Kameno Y, Marei I, de Nucci G, Ahmetaj-Shala Bet al., 2020, Novel sildenafil nanoformulation as a potential therapy for pulmonary arterial hypertension, Meeting of the British-Pharmacological-Society, Publisher: WILEY, Pages: 2508-2509, ISSN: 0007-1188

Conference paper

Latifi-Pupovci H, Selmonaj M, Ahmetaj-Shala B, Dushi M, Grajqevci Vet al., 2020, Incidence of haematological malignancies in Kosovo-A post "uranium war" concern, PLOS ONE, Vol: 15, ISSN: 1932-6203

Journal article

Ahmetaj-Shala B, Kawai R, Marei I, Nikolakopoulou Z, Shih C-C, Konain B, Reed DM, Mongey R, Kirkby NS, Mitchell JAet al., 2020, A bioassay system of autologous human endothelial, smooth muscle cells and leucocytes for use in drug discovery, phenotyping and tissue engineering, The FASEB Journal, Vol: 34, Pages: 1745-1754, ISSN: 0892-6638

Purpose: Blood vessels are comprised of endothelial and smooth muscle cells. Obtaining both types of cells from vessels of living donors is not possible without invasive surgery. To address this we have devised a strategy whereby human endothelial and smooth muscle cells derived from blood progenitors from the same donor could be cultured with autologous leucocytes to generate a same donor ‘vessel in a dish’ bioassay. Basic procedures: Autologous sets of blood outgrowth endothelial cells (BOECs), smooth muscle cells (BO-SMCs) and leucocytes were obtained from 4 donors. Cells were treated in mono and cumulative co-culture conditions. The endothelial specific mediator endothelin-1 along with interleukin (IL)-6, IL-8, tumour necrosis factor α, and interferon gamma-induced protein 10 were measured under control culture conditions and after stimulation with cytokines.Main findings: Co-cultures remained viable throughout. The profile of individual mediators released from cells was consistent with what we know of endothelial and smooth muscle cells cultured from blood vessels.Principle conclusions: For the first time, we report a proof of concept study where autologous blood outgrowth ‘vascular’ cells and leucocytes were studied alone and in co-culture. This novel bioassay has utility in vascular biology research, patient phenotyping, drug testing and tissue engineering.

Journal article

Marei I, Al Shammari H, Latif N, Ahmetaj-Shala B, Yacoub MH, Chester AH, Mitchell JAet al., 2019, Effect of toll-like receptor antagonists on side specific aortic valve endothelial cells, British-Pharmacology-Society Meeting (Pharmacology), Publisher: WILEY, Pages: 2999-3000, ISSN: 0007-1188

Conference paper

Ahmetaj-Shala B, Kawai R, Marei I, Bhatti F, Gashaw H, Kirkby NS, Mitchell JAet al., 2019, A bioassay system of autologous human endothelial and smooth muscle cells for use in cardiovascular drug discovery and patient phenotyping, British-Pharmacology-Society Meeting (Pharmacology), Publisher: WILEY, Pages: 3040-3041, ISSN: 0007-1188

Conference paper

Mazi SI, Ahmetaj-Shala B, Warner TD, Mitchell JA, Kirkby NSet al., 2019, Omic profiling in healthy volunteers taking celecoxib reveals novel biomarkers regulated by cyclooxygenase-2, British-Pharmacology-Society Meeting (Pharmacology), Publisher: WILEY, Pages: 1628-1628, ISSN: 0306-5251

Conference paper

Kawai R, Ahmetaj-Shala B, Shih CC, Marei I, Bhatti K, Kirkby NS, Mitchell JAet al., 2018, Development of a human autologous 3-cell cytokine release assay that models the vascular wall <i>in vitro</i>, 54th Congress of the European-Societies-of-Toxicology (EUROTOX) - Toxicology Out of the Box, Publisher: ELSEVIER IRELAND LTD, Pages: S114-S114, ISSN: 0378-4274

Conference paper

Ahmetaj-Shala B, Olanipekun M, Tesfai A, MacCallum N, Kirkby N, Qunilan G, Shih C-C, Kawai R, Mumby S, Paul-Clark M, Want E, Mitchell JAet al., 2018, Development of a novel UPLC-MS/MS-based platform to quantify amines, amino acids and methylarginines for applications in human disease phenotyping, Scientific Reports, Vol: 8, ISSN: 2045-2322

Amine quantification is an important strategy in patient stratification and personalised medicine. This is because amines, including amino acids and methylarginines impact on many homeostatic processes. One important pathway regulated by amine levels is nitric oxide synthase (NOS). NOS is regulated by levels of (i) the substrate, arginine, (ii) amino acids which cycle with arginine and (iii) methylarginine inhibitors of NOS. However, biomarker research in this area is hindered by the lack of a unified analytical platform. Thus, the development of a common metabolomics platform, where a wide range of amino acids and methylarginines can be measured constitutes an important unmet need. Here we report a novel high-throughput ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) platform where ≈40 amine analytes, including arginine and methylarginines can be detected and quantified on a molar basis, in a single sample of human plasma. To validate the platform and to generate biomarkers, human plasma from a well-defined cohort of patients before and after coronary artery bypass surgery, who developed systemic inflammatory response syndrome (SIRS), were analysed. Bypass surgery with SIRS significantly altered 26 amine analytes, including arginine and ADMA. Consequently, pathway analysis revealed significant changes in a range of pathways including those associated with NOS.

Journal article

Yen I-C, Shi L-S, Chung M-C, Ahmetaj-Shala B, Chang T-C, Lee S-Yet al., 2018, Antrolone, a Novel Benzoid Derived from Antrodia cinnamomea, Inhibits the LPS-Induced Inflammatory Response in RAW264.7 Macrophage Cells by Balancing the NF-kappa B and Nrf2 Pathways, AMERICAN JOURNAL OF CHINESE MEDICINE, Vol: 46, Pages: 1297-1313, ISSN: 0192-415X

Journal article

Kirkby NS, Sampaio W, Etelvino G, Alves DT, Anders KL, Temponi R, Shala F, Nair AS, Ahmetaj-Shala B, Jiao J, Herschman HR, Wang X, Wahli W, Santos RA, Mitchell JAet al., 2018, Cyclooxygenase-2 Selectively Controls Renal Blood Flow Through a Novel PPAR beta/delta-Dependent Vasodilator Pathway (vol 71, pg 297, 2018), HYPERTENSION, Vol: 71, Pages: e10-e10, ISSN: 0194-911X

Journal article

Kirkby NS, Sampaio W, Etelvino G, Alves D, Anders KL, Temponi R, Shala F, Nair AS, Ahmetaj-Shala B, Jiao J, Herschman HR, Xiaomeng W, Wahli W, Santos RA, Mitchell JAet al., 2018, Cyclooxygenase-2 selectively controls renal blood flow through a novel PPARβ/δ-dependent renal vasodilator pathway, Hypertension, Vol: 71, Pages: 297-305, ISSN: 0194-911X

Cyclooxygenase-2 (COX-2) is an inducible enzyme expressed in inflammation and cancer targeted by nonsteroidal anti-inflammatory drugs. COX-2 is also expressed constitutively in discreet locations where its inhibition drives gastrointestinal and cardiovascular/renal side effects. Constitutive COX-2 expression in the kidney regulates renal function and blood flow; however, the global relevance of the kidney versus other tissues to COX-2–dependent blood flow regulation is not known. Here, we used a microsphere deposition technique and pharmacological COX-2 inhibition to map the contribution of COX-2 to regional blood flow in mice and compared this to COX-2 expression patterns using luciferase reporter mice. Across all tissues studied, COX-2 inhibition altered blood flow predominantly in the kidney, with some effects also seen in the spleen, adipose, and testes. Of these sites, only the kidney displayed appreciable local COX-2 expression. As the main site where COX-2 regulates blood flow, we next analyzed the pathways involved in kidney vascular responses using a novel technique of video imaging small arteries in living tissue slices. We found that the protective effect of COX-2 on renal vascular function was associated with prostacyclin signaling through PPARβ/δ (peroxisome proliferator-activated receptor-β/δ). These data demonstrate the kidney as the principle site in the body where local COX-2 controls blood flow and identifies a previously unreported PPARβ/δ-mediated renal vasodilator pathway as the mechanism. These findings have direct relevance to the renal and cardiovascular side effects of drugs that inhibit COX-2, as well as the potential of the COX-2/prostacyclin/PPARβ/δ axis as a therapeutic target in renal disease.

Journal article

Mitchell JA, Benson J, Shala F, Ahmetaj-Shala B, Kirkby NSet al., 2017, Vascular Prostanoids Paradoxically Amplify Vasoconstriction During Platelet Activation, Scientific Sessions of the American-Heart-Association / Resuscitation Science Symposium, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322

Conference paper

Mitchell JA, Shala F, Ahmetaj-Shala B, Jiao J, Armstrong PC, Chan MV, Crescente M, Warner TD, Herschman HR, Kirkby NSet al., 2017, Novel Tissue-specific Cyclooxygenase-1 Knockout Mice Demonstrate a Dominant Role for Endothelial Cyclooxygenase-1 in Prostacyclin Production, Scientific Sessions of the American-Heart-Association / Resuscitation Science Symposium, Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322

Conference paper

Lee S-Y, Tsai W-C, Lin J-C, Ahmetaj-Shala B, Huang S-F, Chang W-L, Chang T-Cet al., 2017, Astragaloside II promotes intestinal epithelial repair by enhancing L-arginine uptake and activating the mTOR pathway, SCIENTIFIC REPORTS, Vol: 7, ISSN: 2045-2322

Astragaloside II (AS II) extracted from Astragalus membranaceus has been reported to promote tissue wound repair. However, the effect of AS II on inflammatory bowel disease is unknown. We investigated the effects and mechanism of AS II on intestinal wound healing in both in vitro and in vivo models. Human intestinal Caco-2 cells were treated with multiple concentrations of AS II to assess cell proliferation, scratch wound closure, L-arginine uptake, cationic amino acid transporter activity, and activation of the mTOR signaling pathway. These effects were also measured in a mouse model of colitis. AS II promoted wound closure and increased cell proliferation, L-arginine uptake, CAT1 and CAT2 protein levels, total protein synthesis, and phosphorylation of mTOR, S6K, and 4E-BP1 in Caco-2 cells. These effects were suppressed by lysine or rapamycin treatment, suggesting that the enhanced arginine uptake mediates AS II-induced wound healing. Similar results were also observed in vivo. Our findings indicate that AS II can contribute to epithelial barrier repair following intestinal injury, and may offer a therapeutic avenue in treating irritable bowel disease.

Journal article

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