scholarly journals Conophylline Suppresses Pancreatic Stellate Cells and Improves Islet Fibrosis in Goto-Kakizaki Rats

Endocrinology ◽  
2012 ◽  
Vol 153 (2) ◽  
pp. 621-630 ◽  
Author(s):  
Rie Saito ◽  
Satoko Yamada ◽  
Yoritsuna Yamamoto ◽  
Tsutomu Kodera ◽  
Akemi Hara ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Stellate Cells ◽  
Activin A ◽  
Pancreatic Stellate Cells ◽  
Muscle Actin ◽  
Β Cell ◽  
Gk Rats

Activin A is a differentiation factor for β-cells and is effective to promote β-cell neogenesis. Activin A is also an autocrine activator of pancreatic stellate cells, which play a critical role in fibrogenesis of the pancreas. Conophylline (CnP) is a natural compound, which reproduces the effect of activin on β-cell differentiation and promotes β-cell neogenesis when administered in vivo. However, its effect on stellate cells is not known. We therefore investigated the effect of CnP on stellate cells both in vitro and in vivo. Unlike activin A, CnP inhibited activation of cultured stellate cells and reduced the production of collagen. We then analyzed the involvement of stellate cells in islet fibrosis in Goto-Kakizaki (GK) rats, a model of type 2 diabetes mellitus. In pancreatic sections obtained from 6-wk-old GK rats, CD68-positive macrophages and glial fibrillary acidic protein- and α-smooth muscle actin-positive stellate cells infiltrated into islets. Later, the number of macrophages was increased, and the α-smooth muscle actin staining of stellate cells became stronger, indicating the involvement of stellate cells in islet fibrosis in GK rats. When CnP was administered orally for 4 wk, starting from 6 wk of age, invasion of stellate cells and macrophages was markedly reduced and islet fibrosis was significantly improved. The insulin content was twice as high in CnP-treated rats. These results indicate that CnP exerts antifibrotic actions both in vitro and in vivo and improves islet fibrosis in Goto-Kakizaki rats.

Increased contractility of hepatic stellate cells in cirrhosis is mediated by enhanced Ca2+-dependent and Ca2+-sensitization pathways

2011 ◽  
Vol 300 (6) ◽  
pp. G1010-G1021 ◽  
Author(s):  
Masateru Iizuka ◽  
Takahisa Murata ◽  
Masatoshi Hori ◽  
Hiroshi Ozaki
Keyword(s):  
Smooth Muscle ◽  
Hepatic Stellate Cells ◽  
Smooth Muscle Actin ◽  
Stellate Cells ◽  
Regulatory Proteins ◽  
Muscle Actin ◽  
Rock Inhibitor ◽  
Duct Ligation

Activation of hepatic stellate cells (HSCs) results in cirrhosis and portal hypertension due to intrahepatic resistance. Activated HSCs increase their contraction after receptor agonist stimulation; however, the signaling pathways for the regulation of contraction are not fully understood. The aim of this study was to elucidate the change in contractile mechanisms of HSCs after cirrhotic activation. The expression pattern of contractile regulatory proteins was analyzed with quantitative RT-PCR and Western blotting. The phosphorylation levels of myosin light chain (MLC), 17-kDa PKC-potentiated protein phosphatase 1 inhibitor protein (CPI-17), and MLC phosphatase targeting subunit 1 (MYPT1) after endothelin-1 (ET-1) stimulation in culture-activated HSCs were measured using phosphorylation-specific antibodies. In vivo-activated HSCs were isolated from rats subjected to bile duct ligation and repeated dimethylnitrosoamine injections. HSCs showed increased expression of not only α-smooth muscle actin, but also the contractile regulatory proteins MLC kinase (MLCK), Rho kinase 2 (ROCK2), and CPI-17 during HSC activation in vitro. In culture-activated HSCs, ET-1 increased phosphorylation of CPI-17 at Thr18, which was markedly inhibited by the PKC inhibitor Ro-31–8425. ET-1 induced phosphorylation of MYPT1 at Thr853, which was suppressed by the ROCK inhibitor Y-27632. ET-1 induced sustained phosphorylation of MLC at Thr18/Ser19, which was inhibited by both Ro-31–8425 and Y-27632. Consistent with the data obtained from the in vitro study, HSCs isolated from cirrhotic rats showed increased expression of α-smooth muscle actin, MLCK, CPI-17, and ROCK2 compared with HSCs from nontreated rats. Furthermore, MLC phosphorylation in in vivo-activated HSCs was increased, according to enhanced phosphorylation of CPI-17 and MYPT1 in the presence of ET-1. These results suggest that activated HSCs may participate in constriction of hepatic sinusoids in the cirrhotic liver through both Ca2+-dependent (MLCK pathway) and Ca2+-sensitization mechanism (CPI-17 and MYPT1 pathways).

scholarly journals Combination of 13-Cis Retinoic Acid and Lovastatin: Marked Antitumor Potential In Vivo in a Pheochromocytoma Allograft Model in Female Athymic Nude Mice

Endocrinology ◽  
2014 ◽  
Vol 155 (7) ◽  
pp. 2377-2390 ◽  
Author(s):  
Svenja Nölting ◽  
Alessio Giubellino ◽  
Yasin Tayem ◽  
Karen Young ◽  
Michael Lauseker ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Retinoic Acid ◽  
Smooth Muscle Actin ◽  
Treated Group ◽  
Muscle Actin ◽  
Tumor Mass ◽  
Viable Tumor ◽  
Over Time

Currently, there are no reliably effective therapeutic options for metastatic pheochromocytoma (PCC) and paraganglioma. Moreover, there are no therapies that may prevent the onset or progression of tumors in patients with succinate dehydrogenase type B mutations, which are associated with very aggressive tumors. Therefore, we tested the approved and well-tolerated drugs lovastatin and 13-cis-retinoic acid (13cRA) in vitro in an aggressive PCC mouse cell line, mouse tumor tissue-derived (MTT) cells, and in vivo in a PCC allograft nude mouse model, in therapeutically relevant doses. Treatment was started 24 hours before sc tumor cell injection and continued for 30 more days. Tumor sizes were measured from outside by caliper and sizes of viable tumor mass by bioluminescence imaging. Lovastatin showed antiproliferative effects in vitro and led to significantly smaller tumor sizes in vivo compared with vehicle treatment. 13cRA promoted tumor cell growth in vitro and led to significantly larger viable tumor mass and significantly faster increase of viable tumor mass in vivo over time compared with vehicle, lovastatin, and combination treatment. However, when combined with lovastatin, 13cRA enhanced the antiproliferative effect of lovastatin in vivo. The combination-treated mice showed slowest tumor growth of all groups with significantly slower tumor growth compared with the vehicle-treated mice and significantly smaller tumor sizes. Moreover, the combination-treated group displayed the smallest size of viable tumor mass and the slowest increase in viable tumor mass over time of all groups, with a significant difference compared with the vehicle- and 13cRA-treated group. The combination-treated tumors showed highest extent of necrosis, lowest median microvessel density and highest expression of α-smooth muscle actin. The combination of high microvessel density and low α-smooth muscle actin is a predictor of poor prognosis in other tumor entities. Therefore, this drug combination may be a well-tolerated novel therapeutic or preventive option for malignant PCC.

scholarly journals High Glucose Aggravates the Detrimental Effects of Pancreatic Stellate Cells on Beta-Cell Function

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Min Zha ◽  
Wei Xu ◽  
Qing Zhai ◽  
Fengfei Li ◽  
Bijun Chen ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
High Glucose ◽  
Cell Function ◽  
Stellate Cells ◽  
Pancreatic Stellate Cells ◽  
High Concentration ◽  
Gk Rats ◽  
Chop Expression

Background and Aims. We here assess the effects of PSCs onβ-cell function and apoptosisin vivoandin vitro.Materials and Methods.PSCs were transplanted into Wistar and Goto-Kakizaki (GK) rats. Sixteen weeks after transplantation,β-cell function, apoptosis, and islet fibrosis were assessed.In vitrothe effects of PSCs conditioned medium (PSCs-CM) and/or high concentration of glucose on INS-1 cell function was assessed by measuring insulin secretion, INS-1 cell survival, apoptosis, and endoplasmic reticulum stress (ER stress) associated CHOP expression.Results. PSCs transplantation exacerbated the impairedβ-cell function in GK rats, but had no significant effects in Wistar rats.In vitro, PSCs-CM caused impaired INS-1 cell viability and insulin secretion and increased apoptosis, which were more pronounced in the presence of high glucose.Conclusion.Our study demonstrates that PSCs induceβ-cell failurein vitroandin vivo.

? Isoform of smooth muscle actin is expressed in astrocytes in vitro and in vivo

1991 ◽  
Vol 28 (4) ◽  
pp. 601-606 ◽  
Author(s):  
E. Lecain ◽  
F. Alliot ◽  
M. C. Laine ◽  
B. Calas ◽  
B. Pessac
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Muscle Actin

scholarly journals The NH2-terminal peptide of α–smooth muscle actin inhibits force generation by the myofibroblast in vitro and in vivo

2002 ◽  
Vol 157 (4) ◽  
pp. 657-663 ◽  
Author(s):  
Boris Hinz ◽  
Giulio Gabbiani ◽  
Christine Chaponnier
Keyword(s):  
Smooth Muscle ◽  
Granulation Tissue ◽  
Contractile Activity ◽  
Smooth Muscle Actin ◽  
Topical Administration ◽  
Force Generation ◽  
Muscle Actin ◽  
Actin Isoforms

Myofibroblasts are specialized fibroblasts responsible for granulation tissue contraction and the soft tissue retractions occurring during fibrocontractive diseases. The marker of fibroblast-myofibroblast modulation is the neo expression of α–smooth muscle actin (α-SMA), the actin isoform typical of vascular smooth muscle cells that has been suggested to play an important role in myofibroblast force generation. Actin isoforms differ slightly in their NH2-terminal sequences; these conserved differences suggest different functions. When the NH2-terminal sequence of α-SMA Ac-EEED is delivered to cultured myofibroblast in the form of a fusion peptide (FP) with a cell penetrating sequence, it inhibits their contractile activity; moreover, upon topical administration in vivo it inhibits the contraction of rat wound granulation tissue. The NH2-terminal peptide of α–skeletal actin has no effect on myofibroblasts, whereas the NH2-terminal peptide of β–cytoplasmic actin abolishes the immunofluorescence staining for this isoform without influencing α-SMA distribution and cell contraction. The FPs represent a new tool to better understand the specific functions of actin isoforms. Our findings support the crucial role of α-SMA in wound contraction. The α-SMA–FP will be useful for the understanding of the mechanisms of connective tissue remodeling; moreover, it furnishes the basis for a cytoskeleton-dependent preventive and/or therapeutic strategy for fibrocontractive pathological situations.

Alpha-smooth muscle actin in pathological human disc nucleus pulposus cells in vivo and in vitro

2004 ◽  
Vol 12 (4) ◽  
pp. 430-438 ◽  
Author(s):  
Dawn Hastreiter ◽  
Jeannie Chao ◽  
QI Wang ◽  
Richard M. Ozuna ◽  
Myron Spector
Keyword(s):  
Smooth Muscle ◽  
Nucleus Pulposus ◽  
Smooth Muscle Actin ◽  
Muscle Actin ◽  
Nucleus Pulposus Cells ◽  
Alpha Smooth Muscle Actin

scholarly journals The specific NH2-terminal sequence Ac-EEED of alpha-smooth muscle actin plays a role in polymerization in vitro and in vivo.

1995 ◽  
Vol 130 (4) ◽  
pp. 887-895 ◽  
Author(s):  
C Chaponnier ◽  
M Goethals ◽  
P A Janmey ◽  
F Gabbiani ◽  
G Gabbiani ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Actin Polymerization ◽  
Smooth Muscle Actin ◽  
Muscle Actin ◽  
Alpha Smooth Muscle Actin ◽  
Fab Fragment ◽  
Acetyl Group ◽  
Antibody Complex

The blocking effect of the NH2-terminal decapeptide of alpha-smooth muscle (SM) actin AcEEED-STALVC on the binding of the specific monoclonal antibody anti-alpha SM-1 (Skalli, O., P. Ropraz, A. Trzeviak, G. Benzonana, D. Gillessen, and G. Gabbiani. 1986. J. Cell Biol. 103:2787-2796) was compared with that of synthetic peptides modified by changing the acetyl group or by substituting an amino acid in positions 1 to 5. Using immunofluorescence and immunoblotting techniques, anti-alpha SM-1 binding was abolished by the native peptide and by peptides with a substitution in position 5, indicating that AcEEED is the epitope for anti-alpha SM-1. Incubation of anti-alpha SM-1 (or of its Fab fragment) with arterial SM actin increased polymerization in physiological salt conditions; the antibody binding did not hinder the incorporation of the actin antibody complex into the filaments. This action was not exerted on skeletal muscle actin. After microinjection of the alpha-SM actin NH2-terminal decapeptide or of the epitopic peptide into cultured aortic smooth muscle cells, double immunofluorescence for alpha-SM actin and total actin showed a selective disappearance of alpha-SM actin staining, detectable at approximately 30 min. When a control peptide (e.g. alpha-skeletal [SK] actin NH2-terminal peptide) was microinjected, this was not seen. This effect is compatible with the possibility that the epitopic peptide traps a protein involved in alpha-SM actin polymerization during the dynamic filament turnover in stress fibers. Whatever the mechanism, this is the first evidence that the NH2 terminus of an actin isoform plays a role in the regulation of polymerization in vitro and in vivo.

Pancreatic duct obstruction itself induces expression of α smooth muscle actin in pancreatic stellate cells

2003 ◽  
Vol 114 (1) ◽  
pp. 6-14 ◽  
Author(s):  
Shinji Kishi ◽  
Yoshifumi Takeyama ◽  
Takashi Ueda ◽  
Takeo Yasuda ◽  
Makoto Shinzeki ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Pancreatic Duct ◽  
Smooth Muscle Actin ◽  
Stellate Cells ◽  
Pancreatic Stellate Cells ◽  
Muscle Actin ◽  
Duct Obstruction ◽  
Pancreatic Duct Obstruction

scholarly journals Baicalin Ameliorates Pancreatic Fibrosis by Inhibiting the Activation of Pancreatic Stellate Cells in Mice with Chronic Pancreatitis

2021 ◽  
Vol 11 ◽  
Author(s):  
Jianwei Fan ◽  
Lifang Duan ◽  
Nan Wu ◽  
Xiaofan Xu ◽  
Jiaqi Xin ◽  
...  
Keyword(s):  
Chronic Pancreatitis ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Stellate Cells ◽  
Pancreatic Fibrosis ◽  
Pancreatic Stellate Cells ◽  
Type I ◽  
Alpha Smooth Muscle Actin

Pancreatic inflammation and fibrosis are typical pathological features in chronic pancreatitis (CP). Activated pancreatic stellate cells (PSCs) have been regarded as the core event in the development of pancreatic fibrosis and are considered to be the key target for treatment of CP. Baicalin (C21H18O11), the main chemical composition of Baikal skullcap in the traditional Chinese medicines Dachaihu decoction (DCHD) and Xiaochaihu decoction (XCHD), has shown significant effects in the treatment of pancreatic fibrosis in CP mice; however, whether baicalin can inhibit the activation of PSCs and its underlying mechanism remain unclear. In this study, the influence of baicalin on activated PSCs in vitro and in vivo was investigated, and the results showed that Baicalin could significantly ameliorate the degree of pancreatic inflammation and fibrosis, while decreasing the levels of alpha-smooth muscle actin (α-SMA), F4/80 (surface markers of mouse macrophages), nuclear factor kappa-B (NF-κB), monocyte chemotactic protein 1 (MCP-1), and collagen type I alpha 1 (COL1A1)in the pancreas. Moreover, NF-κB and α-SMA were co-expressed in the pancreas of CP mice. Baicalin treatment markedly reduced the expression of co-location of α-SMA and NF-κB. In vitro, the protein expression levels of transforming growth factor-β receptor 1 (TGF-βR1), phosphorylated TGF-β activated kinase 1 p-TAK 1, and NF-κBp65 in PSCs were all remarkably reduced after treatment with baicalin. In addition, baicalin could inhibit MCP-1 mRNA expression in supernatant of activated PSCs, as well as the excessive migration of macrophages. Taken together, our findings indicated that baicalin could inhibit the TGF-β1/TGF-βR1/TAK1/NF-κB signaling pathway of activated PSCs, reduce the secretion of MCP-1, and further decrease the infiltration of macrophages and inflammation cells of the local microenvironment of the pancreas. Thus, this study provides a reliable experimental basis for baicalin in the prevention and treatment of CP.

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