Browsing by Subject "Calpain"

Now showing 1 - 5 of 5
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    A putative role for calpain in demyelination associated with optic neuritis
    (Murcia : F. Hernández, 1999) Banik, N.L.; Shields, D.C.
    Calcium activated neutral proteinase (calpain) is an endopeptidase present in the central nervous system which degrades myelin proteins. To examine the role of calpain in demyelination associated with optic neuritis, immunocytochemical expression of calpain was evaluated in Lewis rats with experimental optic neuritis. Calpain expression was increased in activated microglia, infiltrating macrophages, activated T cells, and reactive astrocytes in experimental optic neuritis compared to controls. Calpain activity and translational expression were also examined by Western blotting studies measuring the extent of myelin protein degradation, calpain-specific fodrin proteolysis, axonal neurofilament degradation, and calpain proenzyme content. Results showed myelin associated glycoprotein and 68 kD neurofilament protein levels were significantly decreased while calpain translational expression and calpain-autolyzed fodrin levels were significantly increased in experimental optic neuritis compared to controls. Thus, increased activity and translational expression of calpain in optic neuritis may be integral to the pathogenesis of this disorder.
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    Calpain-specific breakdown fragment in human drusen
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2024) Orihara, Kana; Kobayashi Otsugu, Momoko; Nakajima, Emi; Walkup, Ryan D.; Wilson, David J.; Shearer, Thomas R.; Azuma, Mitsuyoshi
    Purpose. With aging and age-related macular dystrophy (AMD), proteolytic fragments are deposited in extracellular drusen located between the RPE and Bruch’s membrane. Localized hypoxia may be a risk factor for AMD. Our hypothesis is that following hypoxia, activation of proteolytic enzymes called calpains may cause proteolysis/degeneration of retinal cells and RPE. No direct evidence has yet demonstrated activation of calpains in AMD. The purpose of the present study was to identify calpain-cleaved proteins in drusen. Methods. Seventy-six (76) drusen were analyzed in human eye sections from six normal and twelve AMD human donor eyes. The sections were subjected to immunofluorescence for the calpain-specific 150 kDa breakdown product from α-spectrin, SBDP150-a marker for calpain activation, and for recoverin-a marker for photoreceptor cells. Results. Among 29 nodular drusen, 80% from normal eyes and 90% from AMD eyes stained positive for SBDP150. Among 47 soft drusen, mostly from AMD eyes, 72% stained positive for SBDP150. Thus, the majority of both soft and nodular drusen from AMD donors contained SBDP150. Conclusions. SBDP150 was detected for the first time in soft and nodular drusen from human donors. Our results suggest that calpain-induced proteolysis participates in the degeneration of photoreceptors and/or RPE cells during aging and AMD. Calpain inhibitors may ameliorate AMD progression
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    Comparative study of calcium and calcium-related enzymes with differentiation markers in different ages and muscle types in mdx mice.
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Gaglianone, Rhayanna B.; Bloise, Flavia Fonseca; Carvalho, Tania Maria Ortiga; Santos, Thereza Quirico; Costa, Manoel Luis; Mermelstein, Claudia
    Sarcolemma instability and increased calcium influx in muscle fibers are characteristics of the Duchenne muscular dystrophy. Excessive calcium activates calcium-dependent enzymes, such as calpains (CAPN) and matrix metalloproteases (MMP). Here, we analyzed calcium deposits, the activity of CAPN and MMP and the expression of Myh, SERCA and myogenic regulatory factors in different skeletal muscles during myonecrosis (4-weeks) and regeneration (12-weeks) phases of the mdx muscular pathology. Alizarin red staining was used to assess calcium deposits, casein and gelatin zymography were performed to evaluate CAPN and MMP activity, and qPCR was used to evaluate the expression of Myh, Capn, Atp2a1 and Atp2a2, Myod1 and Myog. We observed the following characteristics in mdx muscles: (i) calcium deposits almost exclusively in mdx muscles, (ii) lower CAPN1 activity in mdx muscles, (iii) higher CAPN2 activity in mdx muscles (only at 12 wks), (iv) autolyzed CAPN activity exclusively in mdx muscles, (v) lower expression of Capn1 and higher expression of Capn2 in mdx muscles; (vi) lower expression of Atp2a1 and Atp2a2 in mdx muscles, (vii) higher MMP (pre pro MMP2, pro MMP2, MMP2 and MMP9) activity in mdx muscles, (viii) MMP2 activity exclusively in mdx muscles at 12 wks, (ix) MMP9 activity exclusively in mdx muscles, (x) higher expression of Myog in mdx muscles at 12 wks, and (xi) lower expression of Myh (Myh7, Myh2, Myh1, Myh4) in mdx muscles, particularly Myh7 and Myh2. The collection of our results provides valuable information for a better characterization of mdx pathology phenotype
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    Persistent mdx diaphragm alterations are accompanied by increased expression and activity of calcium and muscle-specific proteins
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2021) Gaglianone, Rhayanna B.; Fonseca Bloise, Flavia; Lagrota-Candido, Jussara; Mermelstein, Claudia; Quirico-Santos, Thereza
    The mdx mouse model of Duchenne Muscular Dystrophy (DMD) presents sarcolemma instability and develops a mild multi-stage dystrophinopathy characterized by intense myonecrosis with inflammatory infiltrate at 4-weeks; muscular regeneration at 12-weeks and persistent fibrosis onwards. Mdx diaphragm muscle has a more severe phenotype with structural and functional deterioration that closely resembles the diaphragm impairment responsible for DMD human patients' morbidity. Herein, we compared calcium deposits, activity of calciumrelated proteases, and expression of muscle-specific proteins in mdx diaphragm at 4-weeks and 12-weeks. We found increased calcium deposits mainly at 12- weeks, concomitant with high activity of calpains and matrix metalloprotease-9, but decreased expression of Myh4 (Myhc IIb) and Atp2a1 (SERCA1), and high expression of the myogenic regulatory factors Myod1 and Myog. Our results suggest that increased calcium deposits and persistent activity of calcium dependent proteases throughout the disease are involved in the degeneration and regeneration processes in the mdx diaphragm.
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    The role of extracellular and intracellular proteolytic systems in aneurysms of the ascending aorta
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2016) Werner, Isabella; Schack, Stephanie; Richter, Manfred; Stock, Ulrich A.; El-Sayed Ahmad, Ali; Moritz, Anton; Beiras-Fernandez, Andres