Capsella bursa-pastoris (L.) Medic. extract alleviate cataract development by regulating the mitochondrial apoptotic pathway of the lens epithelial cells

ABSTRACTEnteropathogenicEscherichia coli(EPEC) has the ability to antagonize host apoptosis during infection through promotion and inhibition of effectors injected by the type III secretion system (T3SS), but the total number of these effectors and the overall functional relationships between these effectors during infection are poorly understood. EspC produced by EPEC cleaves fodrin, paxillin, and focal adhesion kinase (FAK), which are also cleaved by caspases and calpains during apoptosis. Here we show the role of EspC in cell death induced by EPEC. EspC is involved in EPEC-mediated cell death and induces both apoptosis and necrosis in epithelial cells. EspC induces apoptosis through the mitochondrial apoptotic pathway by provoking (i) a decrease in the expression levels of antiapoptotic protein Bcl-2, (ii) translocation of the proapoptotic protein Bax from cytosol to mitochondria, (iii) cytochromecrelease from mitochondria to the cytoplasm, (iv) loss of mitochondrial membrane potential, (v) caspase-9 activation, (vi) cleavage of procaspase-3 and (vii) an increase in caspase-3 activity, (viii) PARP proteolysis, and (ix) nuclear fragmentation and an increase in the sub-G1population. Interestingly, EspC-induced apoptosis was triggered through a dual mechanism involving both independent and dependent functions of its EspC serine protease motif, the direct cleavage of procaspase-3 being dependent on this motif. This is the first report showing a shortcut for induction of apoptosis by the catalytic activity of an EPEC protein. Furthermore, this atypical intrinsic apoptosis appeared to induce necrosis through the activation of calpain and through the increase of intracellular calcium induced by EspC. Our data indicate that EspC plays a relevant role in cell death induced by EPEC.IMPORTANCEEspC, an autotransporter protein with serine protease activity, has cytotoxic effects on epithelial cells during EPEC infection. EspC causes cytotoxicity by cleaving fodrin, a cytoskeletal actin-associated protein, and focal adhesion proteins (i.e., FAK); interestingly, these proteins are also cleaved during apoptosis and necrosis. Here we show that EspC is able to cause cell death, which is characterized by apoptosis: by dissecting the apoptotic pathway and considering that EspC is translocated by an injectisome, we found that EspC induces the mitochondrial apoptotic pathway. Remarkably, EspC activates this pathway by two distinct mechanisms—either by using or not using its serine protease motif. Thus, we show for the first time that this serine protease motif is able to cleave procaspase-3, thereby reaching the terminal stages of caspase cascade activation leading to apoptosis. Furthermore, this overlapped apoptosis appears to potentiate cell death through necrosis, where EspC induces calpain activation and increases intracellular calcium.

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Lens epithelial cell apoptosis appears to be a common cellular basis for non-congenital cataract development in humans and animals.

The Journal of Cell Biology ◽

10.1083/jcb.130.1.169 ◽

1995 ◽

Vol 130 (1) ◽

pp. 169-181 ◽

Cited By ~ 210

Author(s):

W C Li ◽

J R Kuszak ◽

K Dunn ◽

R R Wang ◽

W Ma ◽

...

Keyword(s):

Epithelial Cell ◽

Epithelial Cells ◽

Cell Apoptosis ◽

Lens Epithelial Cell ◽

Lens Epithelial Cells ◽

Cataract Formation ◽

Cellular Basis ◽

Epithelial Cell Apoptosis ◽

Cataract Development ◽

Cataract Patients

Cataract is a major ocular disease that causes blindness in many developing countries of the world. It is well established that various factors such as oxidative stress, UV, and other toxic agents can induce both in vivo and in vitro cataract formation. However, a common cellular basis for this induction has not been previously recognized. The present study of lens epithelial cell viability suggests such a general mechanism. When lens epithelial cells from a group of 20 cataract patients 12 to 94 years old were analyzed by terminal deoxynucleotidyl transferase (TdT) labeling and DNA fragmentation assays, it was found that all of these patients had apoptotic epithelial cells ranging from 4.4 to 41.8%. By contrast, in eight normal human lenses of comparable age, very few apoptotic epithelial cells were observed. We suggest that cataract patients may have deficient defense systems against factors such as oxidative stress and UV at the onset of the disease. Such stress can trigger lens epithelial cell apoptosis that then may initiate cataract development. To test this hypothesis, it is also demonstrated here that hydrogen peroxide at concentrations previously found in some cataract patients induces both lens epithelial cell apoptosis and cortical opacity. Moreover, the temporal and spatial distribution of induced apoptotic lens epithelial cells precedes development of lens opacification. These results suggest that lens epithelial cell apoptosis may be a common cellular basis for initiation of noncongenital cataract formation.

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Radiation-Induced Alterations in Proliferation, Migration, and Adhesion in Lens Epithelial Cells and Implications for Cataract Development

Bioengineering ◽

10.3390/bioengineering9010029 ◽

2022 ◽

Vol 9 (1) ◽

pp. 29

Author(s):

Graysen Vigneux ◽

Jake Pirkkanen ◽

Taylor Laframboise ◽

Hallie Prescott ◽

Sujeenthar Tharmalingam ◽

...

Keyword(s):

Epithelial Cells ◽

Radiation Effects ◽

Lens Epithelial Cells ◽

Boyden Chamber ◽

X Rays ◽

Functional Changes ◽

Transcriptional Alterations ◽

Transcriptional Changes ◽

Radiation Induced ◽

Cataract Development

The lens of the eye is one of the most radiosensitive tissues. Although the exact mechanism of radiation-induced cataract development remains unknown, altered proliferation, migration, and adhesion have been proposed as factors. Lens epithelial cells were exposed to X-rays (0.1–2 Gy) and radiation effects were examined after 12 h and 7 day. Proliferation was quantified using an MTT assay, migration was measured using a Boyden chamber and wound-healing assay, and adhesion was assessed on three extracellular matrices. Transcriptional changes were also examined using RT-qPCR for a panel of genes related to these processes. In general, a nonlinear radiation response was observed, with the greatest effects occurring at a dose of 0.25 Gy. At this dose, a reduction in proliferation occurred 12 h post irradiation (82.06 ± 2.66%), followed by an increase at 7 day (116.16 ± 3.64%). Cell migration was increased at 0.25 Gy, with rates 121.66 ± 6.49% and 232.78 ± 22.22% greater than controls at 12 h and 7 day respectively. Cell adhesion was consistently reduced above doses of 0.25 Gy. Transcriptional alterations were identified at these same doses in multiple genes related to proliferation, migration, and adhesion. Overall, this research began to elucidate the functional changes that occur in lens cells following radiation exposure, thereby providing a better mechanistic understanding of radiation-induced cataract development.

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Over-expression of translationally controlled tumor protein in lens epithelial cells seems to be associated with cataract development

Transgenic Research ◽

10.1007/s11248-009-9283-y ◽

2009 ◽

Vol 18 (6) ◽

pp. 953-960 ◽

Cited By ~ 5

Author(s):

Min-Jeong Kim ◽

Jungmook Lyu ◽

Kyu-Been Sohn ◽

Miyoung Kim ◽

Myeong-Chan Cho ◽

...

Keyword(s):

Epithelial Cells ◽

Lens Epithelial Cells ◽

Over Expression ◽

Translationally Controlled Tumor Protein ◽

Cataract Development

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The Canonical Intrinsic Mitochondrial Death Pathway Has a Non-apoptotic Role in Signaling Lens Cell Differentiation

Journal of Biological Chemistry ◽

10.1074/jbc.m414270200 ◽

2005 ◽

Vol 280 (23) ◽

pp. 22135-22145 ◽

Cited By ~ 68

Author(s):

Gregory F. Weber ◽

A. Sue Menko

Keyword(s):

Cell Death ◽

Cell Differentiation ◽

Epithelial Cells ◽

High Expression ◽

Lens Epithelial Cells ◽

Apoptotic Pathway ◽

Stage Of Development ◽

Cell Death Pathway ◽

Short Term Exposure ◽

Lens Cell

The mitochondrial cell death pathway is known for its role in signaling apoptosis. Here, we describe a novel function for the mitochondrial cell death pathway in signaling initiation of differentiation in the developing lens. Most remarkably, we induced lens cell differentiation by short-term exposure of lens epithelial cells to the apoptogen staurosporine. Activation of apoptosis-related pathways induced lens epithelial cells to express differentiation-specific markers and to undergo morphogenetic changes that led to formation of the lens-like structures known as lentoids. The fact that multiple stages of differentiation are expressed at a single stage of development in the embryonic lens made it possible to precisely determine the timing of expression of proteins associated with the apoptotic pathway. We discovered that there was high expression in the lens equatorial epithelium (the region of the lens in which differentiation is initiated) of pro-apoptotic molecules such as Bax and Bcl-xS and release of cytochrome c from mitochondria. Furthermore, we found significant caspase-3-like activity in the equatorial epithelium, yet this activity was far lower than that associated with lens cell apoptosis. These apoptotic pathways are likely regulated by the concurrent expression of prosurvival molecules, including Bcl-2 and Bcl-xL; phosphorylation of Bad; and high expression of inhibitor of apoptosis proteins chicken IAP1, IAP3, and survivin. This finding suggests that prosurvival pathways allow pro-apoptotic molecules to function as molecular switches in the differentiation process without tipping the balance toward apoptosis. We call this process apoptosis-related Bcl-2- and caspase-dependent (ABC) differentiation.

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Platelet Microtubule Subunit Proteins

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657068 ◽

1979 ◽

Vol 42 (05) ◽

pp. 1630-1633 ◽

Cited By ~ 3

Author(s):

A G Castle ◽

N Crawford

Keyword(s):

Epithelial Cells ◽

Gel Electrophoresis ◽

Blood Platelets ◽

Polyacrylamide Gel Electrophoresis ◽

Polyacrylamide Gel ◽

Lens Epithelial Cells ◽

Molecular Weights ◽

Kinetics Of ◽

Microtubular Structures

SummaryBlood platelets contain microtubule proteins (tubulin and HMWs) which can be polymerised “in vitro” to form structures which resemble the microtubules seen in the intact platelet. Platelet tubulin is composed of two non-identical subunits a and p tubulin which have molecular weights around 55,000 but can be resolved in alkaline SDS-polyacrylamide gel electrophoresis. These subunits associate as dimers with sedimentation coefficients of about 5.7 S although it is not known whether the dimer protein is a homo- or hetero-dimer. The dimer tubulin binds the anti-mitotic drug colchicine and the kinetics of this binding are similar to those reported for neurotubulins. Platelet microtubules also contain two HMW proteins which appear to be essential and integral components of the fully assembled microtubule. These proteins have molecular weights greater than 200,000 daltons. Fluorescent labelled antibodies to platelet and brain tubulins stain long filamentous microtubular structures in bovine lens epithelial cells and this pattern of staining is prevented by exposing the cells to conditions known to cause depolymerisation of cell microtubules.

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