Article

Caspase-7: A protease involved in apoptosis and inflammation

Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium
The international journal of biochemistry & cell biology (Impact Factor: 4.05). 09/2009; 42(1):21-4. DOI: 10.1016/j.biocel.2009.09.013
Source: PubMed

ABSTRACT

Caspase-7 was considered to be redundant with caspase-3 because these related cysteine proteases share an optimal peptide recognition sequence and have several endogenous protein substrates in common. In addition, both caspases are proteolytically activated by the initiator caspase-8 and -9 during death receptor- and DNA-damage-induced apoptosis, respectively. However, a growing body of biochemical and physiological data indicate that caspase-7 also differs in significant ways from caspase-3. For instance, several substrates are specifically cleaved by caspase-7, but not caspase-3. Moreover, caspase-7 activation requires caspase-1 inflammasomes under inflammatory conditions, while caspase-3 processing proceeds independently of caspase-1. Finally, caspase-7 deficient mice are resistant to endotoxemia, whereas caspase-3 knockout mice are susceptible. These findings suggest that specifically interfering with caspase-7 activation may hold therapeutic value for the treatment of cancer and inflammatory ailments.

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Available from: ncbi.nlm.nih.gov
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    • "Previously, it was generally believed that caspase-7 was not present in the CNS, not activated if present, or even if activated, ineffective in inducing apoptosis[22]. Furthermore , because caspase-7 exhibits a high degree of homology with caspase-3, it was speculated that caspase-7 simply served as a redundant version of caspase-3, and thus did not play a critical role in the apoptosis cascade[22]. However, it was later determined that caspase-7 cleaves exclusive substrates different from those of caspase-3, such as kinectin and co-chaperone P23[23– 25]. "
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    ABSTRACT: Axonal injury of the optic nerve (ON) is involved in various ocular diseases, such as glaucoma and traumatic optic neuropathy, which leads to apoptotic death of retinal ganglion cells (RGCs) and loss of vision. Caspases have been implicated in RGC pathogenesis. However, the role of caspase-7, a functionally unique caspase, in ON injury and RGC apoptosis has not been reported previously. The purpose of this study is to evaluate the role of caspase-7 in ON injury-induced RGC apoptosis. C57BL/6 (wildtype, WT) and caspase-7 knockout (Casp7 (-/-) ) mice were used. We show that ON crush activated caspase-7 and calpain-1, an upstream activator of caspase-7, in mouse RGCs, as well as hydrolysis of kinectin and co-chaperone P23, specific substrates of caspase-7. ON crush caused a progressive loss of RGCs to 28 days after injury. Knockout of caspase-7 partially and significantly protected against the ON injury-induced RGC loss; RGC density at 28 days post ON crush in Casp7 (-/-) mice was approximately twice of that in WT ON injured retinas. Consistent with changes in RGC counts, spectral-domain optical coherence tomography analysis revealed that ON crush significantly reduced the in vivo thickness of the ganglion cell complex layer (including ganglion cell layer, nerve fiber layer, and inner plexiform layer) in the retina. The ON crush-induced thinning of retinal layer was significantly ameliorated in Casp7 (-/-) mice when compared to WT mice. Moreover, electroretinography analysis demonstrated a decline in the positive component of scotopic threshold response amplitude in ON crushed eyes of the WT mice, whereas this RGC functional response was significantly higher in Casp7 (-/-) mice at 28 days post injury. Altogether, our findings indicate that caspase-7 plays a critical role in ON injury-induced RGC death, and inhibition of caspase-7 activity may be a novel therapeutic strategy for glaucoma and other neurodegenerative diseases of the retina.
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    • "The recurrent elimination of hair follicle keratinocytes by apoptosis is a process involving caspases (reviewed in Botchkareva et al. 2006). Caspase-7 belongs to the trio of apoptotic executors but also has been shown to participate in inflammation (Lamkanfi and Kanneganti 2010). Additionally , activated caspase-7 has been reported in nonapoptotic cells in relation to cell differentiation (Matalova et al. 2012; Svandova et al. 2014). "
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    • "During the last few years, an extensive research of apoptosis becomes increasingly publicized (Elmore, 2007; Lockshin and Zakeri, 2007; Fulda, 2008; 2009; 2010; Li, 2008; Fulda and Debatin, 2008; Taylor et al., 2008; Vazquez et al., 2008; Youle and Strasser, 2008; Chen and Pervaiz, 2009; Deng et al., 2009; Engel and Henshall, 2009; Lu and El-Deiry, 2009; Circu and Aw; 2010; da Fonseca et al., 2010; Fulda and Pervaiz, 2010; Galluzzi et al., 2010; Lamkanfi and Kanneganti, 2010; Speidel, 2010). This wealth of literature is elaborated for investigating the mechanisms by which different proteins and enzymes are altered and consequently lead to deregulation of apoptosis that is implicated in different diseases (Zhivotovsky and Orrenius, 2010) such as cancers (Chen and Lai, 2009; Buggins and Pepper, 2010; Pennarun et al., 2010), immunologic disorders (Elkon, 2006; Muñoz et al., 2010), neurodegenerative diseases (Yin and Dong, 2003), respiratory diseases; COPD (Makriset et al., 2009), pulmonary hypertension (Jurasz et al., 2010), acute respiratory Distress Syndrome (ARDS) (Galani et al., 2010) and many others. "

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