sajal chakraborti - Academia.edu (original) (raw)

Papers by sajal chakraborti

Research paper thumbnail of Pulmonary Smooth Muscle

Matrix Metalloproteinase-2-Mediated Inhibition of Na -Dependent Ca Uptake by Superoxide Radicals ... more Matrix Metalloproteinase-2-Mediated Inhibition of Na -Dependent Ca Uptake by Superoxide Radicals (O2 .7 ) in Microsomes of Pulmonary Smooth Muscle Amritlal Mandal, Tapati Chakraborti, Sudip Das, Biswarup Ghosh, Amarnath Ghosh and Sajal Chakraborti Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India Division of Electron Microscopy, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme XM, Kolkata 700010, India

Research paper thumbnail of Role of PKCζ‐NADPH oxidase signaling axis in PKCα‐mediated Giα2 phosphorylation for inhibition of adenylate cyclase activity by angiotensin II in pulmonary artery smooth muscle cells

Cell Biology International

Research paper thumbnail of Targeting Mitochondria for Therapy of Cardiovascular Disease

Modulation of Oxidative Stress in Heart Disease

Research paper thumbnail of Role of PLD−PKCζ signalling axis in p47phox phosphorylation for activation of NADPH oxidase by angiotensin II in pulmonary artery smooth muscle cells

Cell Biology International

Research paper thumbnail of Protective role of epigallocatechin-3-gallate in NADPH oxidase-MMP2-Spm-Cer-S1P signalling axis mediated ET-1 induced pulmonary artery smooth muscle cell proliferation

Journal of Cell Communication and Signaling

Research paper thumbnail of Functional attribution of LdISP, an endogenous serine protease inhibitor from Leishmania donovani in promoting infection

Biochimie, 2018

Leishmaniasis, a parasitic disease caused by unicellular eukaryotic protozoa of the genus Leishma... more Leishmaniasis, a parasitic disease caused by unicellular eukaryotic protozoa of the genus Leishmania, affects more than 12 million people worldwide. Events of leishmaniasis are based on the infection of the mammalian host, precisely macrophages, where both host and parasite derived proteases and endogenous inhibitors are significant. Pathogen derived protease inhibitors have generated considerable interest as they often act as an agent promoting infection and parasitic survivability. An endogenous serine protease inhibitor from Indian strain of Leishmania donovani was previously identified by our group and named as LdISP. It has been found to inhibit neutrophil elastase (NE), responsible for natural inflammation process. However, LdISP's role in progression of infection or the proteomics based structural exposition has not been explored. The present study is aimed to localize and validate the potential role of LdISP in infectivity. We found that LdISP localized endogenously and ...

Research paper thumbnail of Role of ADP ribosylation factor6− Cytohesin1−PhospholipaseD signaling axis in U46619 induced activation of NADPH oxidase in pulmonary artery smooth muscle cell membrane

Archives of Biochemistry and Biophysics

Treatment of human pulmonary artery smooth muscle cells (HPASMCs) with the thromboxane A2 recepto... more Treatment of human pulmonary artery smooth muscle cells (HPASMCs) with the thromboxane A2 receptor antagonist, SQ29548 inhibited U46619 stimulation of phospholipase D (PLD) and NADPH oxidase activities in the cell membrane. Pretreatment with apocynin inhibited U46619 induced increase in NADPH oxidase activity. The cell membrane contains predominantly PLD2 along with PLD1 isoforms of PLD. Pretreatment with pharmacological and genetic inhibitors of PLD2, but not PLD1, attenuated U46619 stimulation of NADPH oxidase activity. U46619 stimulation of PLD and NADPH oxidase activities were insensitive to BFA and Clostridium botulinum C3 toxin; however, pretreatment with secinH3 inhibited U46619 induced increase in PLD and NADPH oxidase activities suggesting a major role of cytohesin in U46619-induced increase in PLD and NADPH oxidase activities. Arf-1, Arf-6, cytohesin-1 and cytohesin-2 were observed in the cytosolic fraction, but only Arf-6 and cytohesin-1 were translocated to the cell membrane upon treatment with U46619. Coimmunoprecipitation study showed association of Arf-6 with cytohesin-1 in the cell membrane fraction. In vitro binding of GTPγS with Arf-6 required the presence of cytohesin-1 and that occurs in BFA insensitive manner. Overall, BFA insensitive Arf6-cytohesin1 signaling axis plays a pivotal role in U46619-mediated activation of PLD leading to stimulation of NADPH oxidase activity in HPASMCs.

Research paper thumbnail of Inhibition of pro-/active MMP-2 by green tea catechins and prediction of their interaction by molecular docking studies

Molecular and Cellular Biochemistry, 2016

Matrix metalloproteinases (MMPs) play a crucial role in developing different types of lung diseas... more Matrix metalloproteinases (MMPs) play a crucial role in developing different types of lung diseases, e.g., pulmonary arterial hypertension (PAH). Green tea polyphenolic catechins such as EGCG and ECG have been shown to ameliorate various types of diseases including PAH. Our present study revealed that among the four green tea catechins (EGCG, ECG, EC, and EGC), EGCG and ECG inhibit pro-/active MMP-2 activities in pulmonary artery smooth muscle cell (PASMC) culture supernatant. Based on the above, we investigated the interactions of pro-/active MMP-2 with the green tea catechins by computational methods. In silico analysis revealed a strong interaction of pro-/active MMP-2 with EGCG/ECG, and galloyl group has been observed to be responsible for this interaction. The in silico analysis corroborated our experimental observation that EGCG and ECG are active in preventing both the proMMP-2 and MMP-2 activities. Importantly, these two catechins appeared to be better inhibitors for proMMP-2 in comparison to MMP-2 as revealed by gelatin zymogram and also by molecular docking studies. In many type of cells, activation of proMMP-2 occurs via an increase in the level of MT1-MMP (MMP-14). We, therefore, determined the interactions of MT1-MMP with the green tea catechins by molecular docking analysis. The study revealed a strong interaction of MT1-MMP with EGCG/ECG, and galloyl group has been observed to be responsible for the interaction.

Research paper thumbnail of Inhibition of MMP-9 by green tea catechins and prediction of their interaction by molecular docking analysis

Biomedicine & Pharmacotherapy, 2016

Green tea polyphenolic catechins have been shown to prevent various types of diseases such as pul... more Green tea polyphenolic catechins have been shown to prevent various types of diseases such as pulmonary hypertension (PAH), cancer and cardiac and neurological disorders. Matrix metalloproteinases (MMPs) play an important role in the development of PAH. The present study demonstrated that among the four green tea catechins (EGCG, ECG, EC and EGC), EGCG and ECG inhibit pro-/active MMP-9 activities in pulmonary artery smooth muscle cell culture supernatant. Based on the above, we investigated the interactions of pro-/active MMP-9 with the green tea catechins by computational methods. In silico molecular docking analysis revealed a strong interaction between pro-/active MMP-9 and EGCG/ECG, and galloyl group appears to be responsible for this enhanced interaction. The molecular docking studies corroborate our experimental observation that EGCG and ECG are mainly active in preventing both the proMMP-9 and MMP-9 activities.

Research paper thumbnail of Role of hydroxyl radical in the oxidant H202- mediated Ca 2+ release from pulmonary smooth muscle mitochondria

Research paper thumbnail of Exercise and Matrix Metalloproteases in Health and Disease: A Brief Overview

Research paper thumbnail of Oxidant, Mitochondria and Calcium

Cell Signal, 1999

Mitochondria are active in the continuous generation of reactive oxygen species (ROS), (e.g., sup... more Mitochondria are active in the continuous generation of reactive oxygen species (ROS), (e.g., superoxide), thereby favouring a situation of mitochondrial oxidative stress. Under oxidative stress—for example, ischaemia–reoxygenation injury to cells—mitochondria form superoxide, which in turn is converted to hydrogen peroxide and the potent reactive species, hydroxyl radical. Alternatively, mitochondrial superoxide may react with nitric oxide to form potent oxidant peroxynitrite

Research paper thumbnail of Localization of m-calpain and calpastatin and studies of their association in pulmonary smooth muscle endoplasmic reticulum

Biochimica Et Biophysica Acta General Subjects, Sep 30, 2007

Calpain and calpastatin have been demonstrated to play many physiological roles in a variety of s... more Calpain and calpastatin have been demonstrated to play many physiological roles in a variety of systems. It, therefore, appears important to study their localization and association in different suborganelles. Using immunoblot studies, we have identified 80 kDa m-calpain in both lumen and membrane of ER isolated from bovine pulmonary artery smooth muscle. Treatment of the ER with Na 2 CO 3 and proteinase K demonstrated that 80 kDa catalytic subunit and 28 kDa regulatory subunit (Rs) of m-calpain, and the 110-kDa and 70-kDa calpastatin (Cs) forms are localized in the cytosolic side of the ER membrane. Coimmunoprecipitation studies revealed that m-calpain is associated with calpastatin in the cytosolic face of the ER membrane. We have also identified m-calpain activity both in the ER membrane and lumen by casein-zymography. The caseinzymogram has also been utilized to demonstrate differential pattern of the effects of reversible and irreversible cysteine protease inhibitors on mcalpain activity. Thus, a potential site of Cs regulation of m-calpain activity is created by positioning Cs, 80 kDa and 28 kDa m-calpain in the cytosolic face of ER membrane. However, such is not the case for the 80-kDa m-calpain found within the lumen of the ER because of the conspicuous absence of 28 kDa Rs of m-calpain and Cs in this locale.

Research paper thumbnail of �-Adrenergic Mechanisms in Cardiac Diseases

Research paper thumbnail of Role of Hydroxyl Radical in the Stimulation of Arachidonic Acid Release Caused by H2O2 in Pulmonary Smooth Muscle Cells : Protective Effect of Anion C Hannel Blocker

Molecular and Cellular Biochemistry, 1995

We sought to investigate role of hydroxyl radical (OH.) in H2O2 caused stimulation of arachidonic... more We sought to investigate role of hydroxyl radical (OH.) in H2O2 caused stimulation of arachidonic acid (AA) release from rabbit pulmonary arterial smooth muscle cells, and to ascertain protective effect of the anion channel blocker DIDS in this phenomenon. Exposure of the smooth muscle cells to the oxidant H2O2 (1mM) stimulates iron release and enhances AA liberation from the cells. Pretreatment of the cells with either deferoxamine (DFO) or dimethyl thiourea (DMTU) markedly reduces AA release and prevents OH. production without causing any appreciable reduction of iron release caused by H2O2. Simultaneous treatment of either DFO or DMTU with H2O2 significantly reduces AA release, and also prevents OH. production without causing any significant reduction of iron release. In contrast, addition of either DFO or DMTU even 2 min after exposure of the cells to H2O2 does not cause any significant reduction of AA release, OH. production and iron release. Pretreatment of the cells with DIDS markedly reduces AA release caused by H2O2 without producing any discernible reduction of iron release, and OH. production.

Research paper thumbnail of Submitochondrial localization of associated �-calpain and calpastatin

Arch Biochem Biophys, 2008

Recently, we have reported the presence of calpain-calpastatin system in mitochondria of bovine p... more Recently, we have reported the presence of calpain-calpastatin system in mitochondria of bovine pulmonary smooth muscle [P. Kar, T. Chakraborti, S. Roy, R. Choudhury, S. Chakraborti, Arch. Biochem. Biophys. 466 (2007) 290-299]. Herein, we report its localization in the mitochondria. Immunoblot, immunoelectron microscopy and casein zymographic studies suggest that l-calpain and calpastatin are present in the inner mitochondrial membrane; but not in the outer mitochondrial membrane or in the inter membrane space or in the matrix of the mitochondria. Co-immunoprecipitation studies suggest that l-calpain-calpastatin is associated in the inner mitochondrial membrane. Additionally, the proteinase K and sodium carbonate treatments of the mitoplasts revealed that l-calpain is integrally and calpastatin is peripherally embedded to the outer surface of inner mitochondrial membrane. These studies indicate that an association between l-calpain and calpastatin occurs in the inner membrane towards the inter membrane space of the mitochondria, which provides better insight about the protease regulation towards initiation of apoptotic processes mediated by mitochondria.

Research paper thumbnail of Studies on DNA, RNA and protein synthesis in Malathion treated germinating seeds of Vigna Sinenses (L): effect of plant growth hormone supplementation

International Journal of Environmental Studies, 1982

Studies have shown that malathion causes differential inhibition in the uptakes of C‐uracil, C‐le... more Studies have shown that malathion causes differential inhibition in the uptakes of C‐uracil, C‐leucine and H‐thymidine, the radioactive precursors of RNA, protein and DNA respectively, when compared to the control seeds. The rate of RNA, protein and DNA synthesis were also found to be inhibited under malathion exposed conditions (above 50 ppm), in a dose dependent manner. On simultaneous application

Research paper thumbnail of Μ-Calpain mediated cleavage of the Na+/Ca2+ exchanger in isolated mitochondria under A23187 induced Ca2+ stimulation

Archives of Biochemistry and Biophysics, 2009

Treatment of bovine pulmonary artery smooth muscle mitochondria with the calcium ionophore, A2318... more Treatment of bovine pulmonary artery smooth muscle mitochondria with the calcium ionophore, A23187 (0.2μM) stimulates μ-calpain activity and subsequently cleaves Na+/Ca2+ exchanger (NCX). Pretreatment of the A23187 treated mitochondria with the calpain inhibitors, calpeptin or MDL28170 or with Ca2+ chelator, EGTA does not cleave NCX. Treatment of the mitochondria with A23187 increases Ca2+ level in the mitochondria, which subsequently dissociates μ-calpain–calpastatin association leading to the activation of μ-calpain. Immunoblot study of the A23187 treated mitochondria with the NCX polyclonal antibody indicates the degradation of mitochondrial inner membrane NCX (110kDa) resulting in the doublet of ∼54–56kDa NCX fragments. Moreover, in vitro cleavage of mitochondrial purified NCX by mitochondrial purified μ-calpain supports our conclusion. This cleavage of NCX may be interpreted as the main cause of Ca2+ overload and could lay a key role in the activation of apoptotic process in pulmonary smooth muscle.

Research paper thumbnail of Cross talk between MMP2-Spm-Cer-S1P and ERK1/2 in proliferation of pulmonary artery smooth muscle cells under angiotensin II stimulation

Archives of biochemistry and biophysics, Jan 20, 2016

The aim of the present study is to establish the mechanism associated with the proliferation of P... more The aim of the present study is to establish the mechanism associated with the proliferation of PASMCs under ANG II stimulation. The results showed that treatment of PASMCs with ANG II induces an increase in cell proliferation and 100 nM was the optimum concentration for maximum increase in proliferation of the cells. Pretreatment of the cells with AT1, but not AT2, receptor antagonist inhibited ANG II induced cell proliferation. Pretreatment with pharmacological and genetic inhibitors of sphingomyelinase (SMase) and sphingosine kinase (SPHK) prevented ANG II-induced cell proliferation. ANG II has also been shown to induce SMase activity, SPHK phosphorylation and S1P production. In addition, ANG II caused an increase in proMMP-2 expression and activation, ERK1/2 phosphorylation and NADPH oxidase activation. Upon inhibition of MMP-2, SMase activity and S1P level were curbed leading to inhibition of cell proliferation. SPHK was phosphorylated by ERK1/2 during ET-1 stimulation of the c...

Research paper thumbnail of Identification, purification and partial characterization of tissue inhibitor of matrix metalloproteinase-2 in bovine pulmonary artery smooth muscle

Molecular and Cellular Biochemistry, Dec 1, 2003

Research paper thumbnail of Pulmonary Smooth Muscle

Matrix Metalloproteinase-2-Mediated Inhibition of Na -Dependent Ca Uptake by Superoxide Radicals ... more Matrix Metalloproteinase-2-Mediated Inhibition of Na -Dependent Ca Uptake by Superoxide Radicals (O2 .7 ) in Microsomes of Pulmonary Smooth Muscle Amritlal Mandal, Tapati Chakraborti, Sudip Das, Biswarup Ghosh, Amarnath Ghosh and Sajal Chakraborti Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India Division of Electron Microscopy, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme XM, Kolkata 700010, India

Research paper thumbnail of Role of PKCζ‐NADPH oxidase signaling axis in PKCα‐mediated Giα2 phosphorylation for inhibition of adenylate cyclase activity by angiotensin II in pulmonary artery smooth muscle cells

Cell Biology International

Research paper thumbnail of Targeting Mitochondria for Therapy of Cardiovascular Disease

Modulation of Oxidative Stress in Heart Disease

Research paper thumbnail of Role of PLD−PKCζ signalling axis in p47phox phosphorylation for activation of NADPH oxidase by angiotensin II in pulmonary artery smooth muscle cells

Cell Biology International

Research paper thumbnail of Protective role of epigallocatechin-3-gallate in NADPH oxidase-MMP2-Spm-Cer-S1P signalling axis mediated ET-1 induced pulmonary artery smooth muscle cell proliferation

Journal of Cell Communication and Signaling

Research paper thumbnail of Functional attribution of LdISP, an endogenous serine protease inhibitor from Leishmania donovani in promoting infection

Biochimie, 2018

Leishmaniasis, a parasitic disease caused by unicellular eukaryotic protozoa of the genus Leishma... more Leishmaniasis, a parasitic disease caused by unicellular eukaryotic protozoa of the genus Leishmania, affects more than 12 million people worldwide. Events of leishmaniasis are based on the infection of the mammalian host, precisely macrophages, where both host and parasite derived proteases and endogenous inhibitors are significant. Pathogen derived protease inhibitors have generated considerable interest as they often act as an agent promoting infection and parasitic survivability. An endogenous serine protease inhibitor from Indian strain of Leishmania donovani was previously identified by our group and named as LdISP. It has been found to inhibit neutrophil elastase (NE), responsible for natural inflammation process. However, LdISP's role in progression of infection or the proteomics based structural exposition has not been explored. The present study is aimed to localize and validate the potential role of LdISP in infectivity. We found that LdISP localized endogenously and ...

Research paper thumbnail of Role of ADP ribosylation factor6− Cytohesin1−PhospholipaseD signaling axis in U46619 induced activation of NADPH oxidase in pulmonary artery smooth muscle cell membrane

Archives of Biochemistry and Biophysics

Treatment of human pulmonary artery smooth muscle cells (HPASMCs) with the thromboxane A2 recepto... more Treatment of human pulmonary artery smooth muscle cells (HPASMCs) with the thromboxane A2 receptor antagonist, SQ29548 inhibited U46619 stimulation of phospholipase D (PLD) and NADPH oxidase activities in the cell membrane. Pretreatment with apocynin inhibited U46619 induced increase in NADPH oxidase activity. The cell membrane contains predominantly PLD2 along with PLD1 isoforms of PLD. Pretreatment with pharmacological and genetic inhibitors of PLD2, but not PLD1, attenuated U46619 stimulation of NADPH oxidase activity. U46619 stimulation of PLD and NADPH oxidase activities were insensitive to BFA and Clostridium botulinum C3 toxin; however, pretreatment with secinH3 inhibited U46619 induced increase in PLD and NADPH oxidase activities suggesting a major role of cytohesin in U46619-induced increase in PLD and NADPH oxidase activities. Arf-1, Arf-6, cytohesin-1 and cytohesin-2 were observed in the cytosolic fraction, but only Arf-6 and cytohesin-1 were translocated to the cell membrane upon treatment with U46619. Coimmunoprecipitation study showed association of Arf-6 with cytohesin-1 in the cell membrane fraction. In vitro binding of GTPγS with Arf-6 required the presence of cytohesin-1 and that occurs in BFA insensitive manner. Overall, BFA insensitive Arf6-cytohesin1 signaling axis plays a pivotal role in U46619-mediated activation of PLD leading to stimulation of NADPH oxidase activity in HPASMCs.

Research paper thumbnail of Inhibition of pro-/active MMP-2 by green tea catechins and prediction of their interaction by molecular docking studies

Molecular and Cellular Biochemistry, 2016

Matrix metalloproteinases (MMPs) play a crucial role in developing different types of lung diseas... more Matrix metalloproteinases (MMPs) play a crucial role in developing different types of lung diseases, e.g., pulmonary arterial hypertension (PAH). Green tea polyphenolic catechins such as EGCG and ECG have been shown to ameliorate various types of diseases including PAH. Our present study revealed that among the four green tea catechins (EGCG, ECG, EC, and EGC), EGCG and ECG inhibit pro-/active MMP-2 activities in pulmonary artery smooth muscle cell (PASMC) culture supernatant. Based on the above, we investigated the interactions of pro-/active MMP-2 with the green tea catechins by computational methods. In silico analysis revealed a strong interaction of pro-/active MMP-2 with EGCG/ECG, and galloyl group has been observed to be responsible for this interaction. The in silico analysis corroborated our experimental observation that EGCG and ECG are active in preventing both the proMMP-2 and MMP-2 activities. Importantly, these two catechins appeared to be better inhibitors for proMMP-2 in comparison to MMP-2 as revealed by gelatin zymogram and also by molecular docking studies. In many type of cells, activation of proMMP-2 occurs via an increase in the level of MT1-MMP (MMP-14). We, therefore, determined the interactions of MT1-MMP with the green tea catechins by molecular docking analysis. The study revealed a strong interaction of MT1-MMP with EGCG/ECG, and galloyl group has been observed to be responsible for the interaction.

Research paper thumbnail of Inhibition of MMP-9 by green tea catechins and prediction of their interaction by molecular docking analysis

Biomedicine & Pharmacotherapy, 2016

Green tea polyphenolic catechins have been shown to prevent various types of diseases such as pul... more Green tea polyphenolic catechins have been shown to prevent various types of diseases such as pulmonary hypertension (PAH), cancer and cardiac and neurological disorders. Matrix metalloproteinases (MMPs) play an important role in the development of PAH. The present study demonstrated that among the four green tea catechins (EGCG, ECG, EC and EGC), EGCG and ECG inhibit pro-/active MMP-9 activities in pulmonary artery smooth muscle cell culture supernatant. Based on the above, we investigated the interactions of pro-/active MMP-9 with the green tea catechins by computational methods. In silico molecular docking analysis revealed a strong interaction between pro-/active MMP-9 and EGCG/ECG, and galloyl group appears to be responsible for this enhanced interaction. The molecular docking studies corroborate our experimental observation that EGCG and ECG are mainly active in preventing both the proMMP-9 and MMP-9 activities.

Research paper thumbnail of Role of hydroxyl radical in the oxidant H202- mediated Ca 2+ release from pulmonary smooth muscle mitochondria

Research paper thumbnail of Exercise and Matrix Metalloproteases in Health and Disease: A Brief Overview

Research paper thumbnail of Oxidant, Mitochondria and Calcium

Cell Signal, 1999

Mitochondria are active in the continuous generation of reactive oxygen species (ROS), (e.g., sup... more Mitochondria are active in the continuous generation of reactive oxygen species (ROS), (e.g., superoxide), thereby favouring a situation of mitochondrial oxidative stress. Under oxidative stress—for example, ischaemia–reoxygenation injury to cells—mitochondria form superoxide, which in turn is converted to hydrogen peroxide and the potent reactive species, hydroxyl radical. Alternatively, mitochondrial superoxide may react with nitric oxide to form potent oxidant peroxynitrite

Research paper thumbnail of Localization of m-calpain and calpastatin and studies of their association in pulmonary smooth muscle endoplasmic reticulum

Biochimica Et Biophysica Acta General Subjects, Sep 30, 2007

Calpain and calpastatin have been demonstrated to play many physiological roles in a variety of s... more Calpain and calpastatin have been demonstrated to play many physiological roles in a variety of systems. It, therefore, appears important to study their localization and association in different suborganelles. Using immunoblot studies, we have identified 80 kDa m-calpain in both lumen and membrane of ER isolated from bovine pulmonary artery smooth muscle. Treatment of the ER with Na 2 CO 3 and proteinase K demonstrated that 80 kDa catalytic subunit and 28 kDa regulatory subunit (Rs) of m-calpain, and the 110-kDa and 70-kDa calpastatin (Cs) forms are localized in the cytosolic side of the ER membrane. Coimmunoprecipitation studies revealed that m-calpain is associated with calpastatin in the cytosolic face of the ER membrane. We have also identified m-calpain activity both in the ER membrane and lumen by casein-zymography. The caseinzymogram has also been utilized to demonstrate differential pattern of the effects of reversible and irreversible cysteine protease inhibitors on mcalpain activity. Thus, a potential site of Cs regulation of m-calpain activity is created by positioning Cs, 80 kDa and 28 kDa m-calpain in the cytosolic face of ER membrane. However, such is not the case for the 80-kDa m-calpain found within the lumen of the ER because of the conspicuous absence of 28 kDa Rs of m-calpain and Cs in this locale.

Research paper thumbnail of �-Adrenergic Mechanisms in Cardiac Diseases

Research paper thumbnail of Role of Hydroxyl Radical in the Stimulation of Arachidonic Acid Release Caused by H2O2 in Pulmonary Smooth Muscle Cells : Protective Effect of Anion C Hannel Blocker

Molecular and Cellular Biochemistry, 1995

We sought to investigate role of hydroxyl radical (OH.) in H2O2 caused stimulation of arachidonic... more We sought to investigate role of hydroxyl radical (OH.) in H2O2 caused stimulation of arachidonic acid (AA) release from rabbit pulmonary arterial smooth muscle cells, and to ascertain protective effect of the anion channel blocker DIDS in this phenomenon. Exposure of the smooth muscle cells to the oxidant H2O2 (1mM) stimulates iron release and enhances AA liberation from the cells. Pretreatment of the cells with either deferoxamine (DFO) or dimethyl thiourea (DMTU) markedly reduces AA release and prevents OH. production without causing any appreciable reduction of iron release caused by H2O2. Simultaneous treatment of either DFO or DMTU with H2O2 significantly reduces AA release, and also prevents OH. production without causing any significant reduction of iron release. In contrast, addition of either DFO or DMTU even 2 min after exposure of the cells to H2O2 does not cause any significant reduction of AA release, OH. production and iron release. Pretreatment of the cells with DIDS markedly reduces AA release caused by H2O2 without producing any discernible reduction of iron release, and OH. production.

Research paper thumbnail of Submitochondrial localization of associated �-calpain and calpastatin

Arch Biochem Biophys, 2008

Recently, we have reported the presence of calpain-calpastatin system in mitochondria of bovine p... more Recently, we have reported the presence of calpain-calpastatin system in mitochondria of bovine pulmonary smooth muscle [P. Kar, T. Chakraborti, S. Roy, R. Choudhury, S. Chakraborti, Arch. Biochem. Biophys. 466 (2007) 290-299]. Herein, we report its localization in the mitochondria. Immunoblot, immunoelectron microscopy and casein zymographic studies suggest that l-calpain and calpastatin are present in the inner mitochondrial membrane; but not in the outer mitochondrial membrane or in the inter membrane space or in the matrix of the mitochondria. Co-immunoprecipitation studies suggest that l-calpain-calpastatin is associated in the inner mitochondrial membrane. Additionally, the proteinase K and sodium carbonate treatments of the mitoplasts revealed that l-calpain is integrally and calpastatin is peripherally embedded to the outer surface of inner mitochondrial membrane. These studies indicate that an association between l-calpain and calpastatin occurs in the inner membrane towards the inter membrane space of the mitochondria, which provides better insight about the protease regulation towards initiation of apoptotic processes mediated by mitochondria.

Research paper thumbnail of Studies on DNA, RNA and protein synthesis in Malathion treated germinating seeds of Vigna Sinenses (L): effect of plant growth hormone supplementation

International Journal of Environmental Studies, 1982

Studies have shown that malathion causes differential inhibition in the uptakes of C‐uracil, C‐le... more Studies have shown that malathion causes differential inhibition in the uptakes of C‐uracil, C‐leucine and H‐thymidine, the radioactive precursors of RNA, protein and DNA respectively, when compared to the control seeds. The rate of RNA, protein and DNA synthesis were also found to be inhibited under malathion exposed conditions (above 50 ppm), in a dose dependent manner. On simultaneous application

Research paper thumbnail of Μ-Calpain mediated cleavage of the Na+/Ca2+ exchanger in isolated mitochondria under A23187 induced Ca2+ stimulation

Archives of Biochemistry and Biophysics, 2009

Treatment of bovine pulmonary artery smooth muscle mitochondria with the calcium ionophore, A2318... more Treatment of bovine pulmonary artery smooth muscle mitochondria with the calcium ionophore, A23187 (0.2μM) stimulates μ-calpain activity and subsequently cleaves Na+/Ca2+ exchanger (NCX). Pretreatment of the A23187 treated mitochondria with the calpain inhibitors, calpeptin or MDL28170 or with Ca2+ chelator, EGTA does not cleave NCX. Treatment of the mitochondria with A23187 increases Ca2+ level in the mitochondria, which subsequently dissociates μ-calpain–calpastatin association leading to the activation of μ-calpain. Immunoblot study of the A23187 treated mitochondria with the NCX polyclonal antibody indicates the degradation of mitochondrial inner membrane NCX (110kDa) resulting in the doublet of ∼54–56kDa NCX fragments. Moreover, in vitro cleavage of mitochondrial purified NCX by mitochondrial purified μ-calpain supports our conclusion. This cleavage of NCX may be interpreted as the main cause of Ca2+ overload and could lay a key role in the activation of apoptotic process in pulmonary smooth muscle.

Research paper thumbnail of Cross talk between MMP2-Spm-Cer-S1P and ERK1/2 in proliferation of pulmonary artery smooth muscle cells under angiotensin II stimulation

Archives of biochemistry and biophysics, Jan 20, 2016

The aim of the present study is to establish the mechanism associated with the proliferation of P... more The aim of the present study is to establish the mechanism associated with the proliferation of PASMCs under ANG II stimulation. The results showed that treatment of PASMCs with ANG II induces an increase in cell proliferation and 100 nM was the optimum concentration for maximum increase in proliferation of the cells. Pretreatment of the cells with AT1, but not AT2, receptor antagonist inhibited ANG II induced cell proliferation. Pretreatment with pharmacological and genetic inhibitors of sphingomyelinase (SMase) and sphingosine kinase (SPHK) prevented ANG II-induced cell proliferation. ANG II has also been shown to induce SMase activity, SPHK phosphorylation and S1P production. In addition, ANG II caused an increase in proMMP-2 expression and activation, ERK1/2 phosphorylation and NADPH oxidase activation. Upon inhibition of MMP-2, SMase activity and S1P level were curbed leading to inhibition of cell proliferation. SPHK was phosphorylated by ERK1/2 during ET-1 stimulation of the c...

Research paper thumbnail of Identification, purification and partial characterization of tissue inhibitor of matrix metalloproteinase-2 in bovine pulmonary artery smooth muscle

Molecular and Cellular Biochemistry, Dec 1, 2003