Increased ROCK1 not ROCK2 in circulating leukocytes in rats with myocardial ischemia/reperfusion

BACKGROUND

Rho-associated protein kinase (ROCK) plays a vital role in the pathogenesis of many cardiovascular diseases. Previous studies have demonstrated that ROCK is overactivated and involved in myocardial ischemia/reperfusion in vivo. But the role of ROCK in circulating leukocytes during myocardial ischemia/reperfusion is not well studied.

MATERIAL AND METHODS

This study was performed to evaluate ROCK activity in circulating leukocytes in rats with myocardial ischemia/reperfusion injury. Myocardial ischemia/reperfusion Wistar rats were subjected to 30-min ischemia followed by 180-min reperfusion. ROCK activity in circulating leukocytes was examined by the phosphorylation state of myosin phosphatase targeting subunit 1, a substrate of ROCK.

RESULTS

ROCK activity significantly increased in leukocytes in rat ischemia/reperfusion models compared to the sham group. ROCK1 not ROCK2 level in circulating leukocytes was significantly elevated in ischemia/reperfusion. Administration of the selective inhibitor of ROCK, fasudil, significantly reduced myocardial infarct size, myocyte apoptosis, and inflammatory cytokine, including interleukin 6 and tumor necrosis factor α. Furthermore, fasudil upregulated ischemia/reperfusion-induced reduction of nitric oxide production.

CONCLUSION

Increased ROCK1 not ROCK2 in circulating leukocytes plays a role in the pathogenesis of myocardial ischemia/reperfusion injury. Inhibition of ROCK1 in circulating leukocytes has an important role in fasudil-induced cardioprotective effects. ROCK1 in circulating leukocytes might be a new biomarker in myocardial ischemia/reperfusion injury.

Elevated plasma interleukin-37 playing an important role in acute coronary syndrome through suppression of ROCK activation

OBJECTIVE

The plasma level of interleukin-37 is elevated in patients with acute coronary syndrome, however, its function during the onset and progress of the disease remains unclear. This study aimed to investigate the clinical significance of IL-37 in acute coronary syndrome and its underlying mechanism.

METHODS

124 patients with acute coronary syndrome and 40 healthy controls were recruited in this study. Plasma interleukin-37 levels were measured in 41 patients with ST elevation myocardial infarction (STEMI), 41 patients with non-STEMI, 42 patients with unstable angina, and 40 controls. Mortality was defined as an event.

RESULTS

In this study, the mean follow-up period was 824±306 days (2-1077 days). 22% (n=27) of patients died. The mortality rate was significantly lower in patients with interleukin-37 serum levels below the median (6.4 pg/mL) than those with interleukin-37 serum levels above 6.4 pg/mL at 36-month follow-up (16% vs. 24%, p=0.02, log rank X2=5.39). Highly concentration of the anti-inflammatory interleukin-37 exerted a protective effect by suppressing the activated Rho Kinase (ROCK) activity in the peripheral blood mononuclear cells in vivo and in vitro after ischemia/reperfusion injury and stimulation of the Rho activator, calpeptin.

CONCLUSIONS

The interleukin-37 level is significantly increased in acute coronary syndrome. Elevated baseline interleukin-37 levels in patients on admission are associated with poor outcomes. Thus, we propose that interleukin-37 could be a biomarker predictive of mortality in acute coronary syndrome. Moreover, this study reveals that the protective effect of interleukin-37 against atherosclerosis may involve the inhibition of ROCK activity.

Induction of predominant tenogenic phenotype in human dermal fibroblasts via synergistic effect of TGF-β and elongated cell shape

Micropattern topography is widely investigated for its role in mediating stem cell differentiation, but remains unexplored for phenotype switch between mature cell types. This study investigated the potential of inducing tenogenic phenotype in human dermal fibroblasts (hDFs) by artificial elongation of cultured cells. Our results showed that a parallel microgrooved topography could convert spread hDFs into an elongated shape and induce a predominant tenogenic phenotype as the expression of biomarkers was significantly enhanced, such as scleraxis, tenomodulin, collagens I, III, VI, and decorin. It also enhanced the expression of transforming growth factor (TGF)-β1, but not α-smooth muscle actin. Elongated hDFs failed to induce other phenotypes, such as adiopogenic, chondrogenic, neurogenic, and myogenic lineages. By contrast, no tenogenic phenotype could be induced in elongated human chondrocytes, although chondrogenic phenotype was inhibited. Exogenous TGF-β1 could enhance the tenogenic phenotype in elongated hDFs at low dose (2 ng/ml), but promoted myofibroblast transdifferentiation of hDFs at high dose (10 ng/ml), regardless of cell shape. Elongated shape also resulted in decreased RhoA activity and increased Rho-associated protein kinase (ROCK) activity. Antagonizing TGF-β or inhibiting ROCK activity with Y27632 or depolymerizing actin with cytochalasin D could all significantly inhibit tenogenic phenotype induction, particularly in elongated hDFs. In conclusion, elongation of cultured dermal fibroblasts can induce a predominant tenogenic phenotype likely via synergistic effect of TGF-β and cytoskeletal signaling.

A combination of increased Rho kinase activity and N-terminal pro-B-type natriuretic peptide predicts worse cardiovascular outcome in patients with acute coronary syndrome. Int J Cardiol. 2013;167:2813-2819. [PMID: 22921817 DOI: 10.1016/j.ijcard.2012.07.007]

BACKGROUND

Recent experimental evidence suggests that the Rho/Rho-kinase (ROCK) system may play an important role in the pathogenesis of acute coronary syndrome (ACS) but there are little clinical data. This study examined if ROCK activity is increased in patients with acute coronary syndrome and if ROCK activity predicts long-term cardiovascular event.

METHOD

Blood samples were collected from 188 patients within 12h after admission for ACS (53% men; aged 70 ± 13) and from 61 control subject. The main outcome measures were all cause mortality, readmission with ACS or congestive heart failure (CHF) from presentation within around 2 years (mean:14.4 ± 7.2 months; range: 0.5 to 26 months).

RESULTS

ROCK activity increased in ST elevation myocardial infarction (STEMI, n=90) (3.33 ± 0.93), non-STEMI (NSTEMI, n=68) (3.37 ± 1.04) and unstable angina (UA, n=30) (2.53 ± 0.59) groups when compared with disease controls (n=31) (2.06 ± 0.38, all p<0.001) and healthy controls (n=30) (1.54 ± 0.43, all p<0.001). There were 24 deaths, 34 readmissions with ACS and 15 admissions with CHF within 2 years. Patients with a high N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high ROCK activity on admission had a five-fold risk of a cardiovascular event (RR: 5.156; 95% CI: 2.180-12.191) when compared to those with low NT-proBNP and low ROCK activity.

CONCLUSION

ROCK activity was increased in patients with ACS, particularly in those with myocardial infarction. The combined usage of both ROCK activity and NT-proBNP might identify a subset of ACS patients at particularly high risk.