Cigarette smoking induces oxidative stress and unfolded protein response (UPR), and is the major risk factor for emphysema and COPD (chronic obstructive pulmonary disease) pathophysiology(1-5), although it is not clear why only few smokers develop COPD or why some non-smokers have COPD. We identified that protein levels of AAA (ATPase associated with diverse cellular activities) molecular chaperone and UPR modulator, p97/VCP (Valosin containing protein), are significantly upregulated in COPD peripheral lungs of smokers as compared to non-smokers. We also confirmed that VCP expression correlates with severity of COPD using lung tissues (Lung Tissue Research Consortium, LTRC) from patients with FEV1% predicted of >80 (mild), 50- 80% (moderate) and <50% (severe). In our preliminary experiments, we confirmed that VCP inhibition in HEK293 cells rescues Nrf2 from proteasomal degradation similar to the levels seen with the proteasomal- inhibitor drug, Velcade/PS341. We verified that VCP inhibition not only rescues Nrf2 but also enhances proteasomal activity and antioxidant gene, NQO1 (NAD(P)H quinone oxidoreductase 1) expression. In addition, we and others recently reported that VCP selectively targets the I:B and unfolded proteins over wt- nascent proteins for proteasomal-degradation or aggregation (7-11) and regulates both UPR and proteasomal activities. The goal of this grant is to dissect the mechanisms of VCP-mediated protein processing in COPD and emphysema. The primary hypothesis of this proposal is that VCP regulates UPR, proteasomal activity, and oxidative stress, and is a critical mediator of COPD pathogenesis. A secondary hypothesis is that selective interference of VCP's ERAD function will not only bypass protein-aggregation and uncontrolled UPR but also rescue the other components associated with the pathophysiology of COPD. The overall projected outcome is an identification of a novel therapeutic site that rescues the pathophysiology of COPD and emphysema by modulating UPR, oxidative stress, and chronic inflammatory signaling.
Specific Aim 1 will determine if VCP play a key role in COPD disease pathogenesis. The correlation of VCP expression to proteolytic activities, apoptosis, and oxidative stress and inflammatory markers in control and COPD subjects will help us evaluate if VCP has a critical UPR modifier function in COPD lung disease. We anticipate elucidating the role of VCP in COPD disease pathogenesis.
Specific Aim 2 will evaluate if other components of VCP protein-complex are critical for COPD disease pathogenesis.
We aim to evaluate the physiological role of VCP associated ubiquitin ligases in COPD by correlating there expression and severity of lung disease to proteolytic activities, apoptosis and inflammatory markers (Aim 1). We anticipate identifying the mechanism(s) of VCP and identifying an effective intervention that leads to the normalization of COPD pathophysiology.
The pathogenesis of COPD lung disease remains incompletely understood and current therapies are inadequate. Our preliminary data demonstrate that p97/VCP and proteasomal pathway is critical step in COPD pathogenesis.
We aim to evaluate the regulatory mechanisms of proteasomal pathway in human lungs from COPD subjects. We anticipate improving our understanding of COPD lung disease and contributing to the development of new and better treatments.
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