The Ser/Thr Protein Kinase Protein-Protein Interaction Map of M. tuberculosis.

Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, the leading cause of death among all infectious diseases. There are 11 eukaryotic-like serine/threonine protein kinases (STPKs) in Mtb, which are thought to play pivotal roles in cell growth, signal transduction and pathogenesis. However, their underlying mechanisms of action remain largely uncharacterized. In this study, using a Mtb proteome microarray, we have globally identified the binding proteins in Mtb for all of the STPKs, and constructed the first STPK protein interaction (KPI) map that includes 492 binding proteins and 1,027 interactions. Bioinformatics analysis showed that the interacting proteins reflect diverse functions, including roles in two-component system, transcription, protein degradation, and cell wall integrity. Functional investigations confirmed that PknG regulates cell wall integrity through key components of peptidoglycan (PG) biosynthesis, e.g. MurC. The global STPK-KPIs network constructed here is expected to serve as a rich resource for understanding the key signaling pathways in Mtb, thus facilitating drug development and effective control of Mtb.

Correlation between resting heart rate and blood glucose level in elderly patients with coronary heart disease and diabetes mellitus / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the correlation between resting heart rate (RHR) and blood glucose level in elderly patients with coronary heart disease (CHD) complicated by diabetes mellitus.</p><p><b>METHODS</b>Between April and July, 2011, a total of 1336 outpatients over 60 years of age recruited from 165 hospitals were asked to complete a questionnaire and received blood glucose and RHR examination. According to baseline RHR, the patients were divided into 3 groups with HRH <70 min-1 (group I, 372 cases), between 70 and 79 min(-1) (group II, 533 cases), and ≥80 min(-1) (group III, 431cases) for analysis of the relationships of RHR with blood glucose control rate.</p><p><b>RESULTS</b>HbA1c levels in the total, male and female patients differed significantly among the 3 groups (F=15.436, 15.436, and 24.270, respectively, P<0.05), and increased in the order from group I to group III. Blood glucose control rate in the total, male and female patients also differed significantly among the 3 groups (χ(2)=13.471, 6.752, and 6.522, respectively, P<0.05), and was significantly lower in group III than in group I (P<0.05). RHR was found to positively correlate with FPG, 2 hPG and HbA1c by Pearson correlation analysis (r=0.058, 0.085, and 0.058, respectively; P<0.05) and multiple linear regression analysis (β=0.075, 0.075, and 0.018, respectively; P<0.05). Multivariable logistic regression equation showed that compared with patients with RHR <70 min-1, the total, male and female patients with RHR ≥80 min(-1) had OR values of blood glucose control failure of 1.99 (95% CI: 1.23-2.37, P<0.05), 1.81 (95% CI: 1.17-2.77, P<0.05), and 2.18 (95% CI: 1.12-3.74, P<0.05), respectively.</p><p><b>CONCLUSION</b>RHR in elderly CHD patients with MD is positively correlated with their blood glucose level, and an increased RHR is associated with an increased risk of poor blood glucose control. Rigorous RHR control in such high-risk patients may prove beneficial for both blood glucose control and secondary prevention of CHD.</p>

Extracellular matrix accumulation and expression of gelatinases and their tissue inhibitors in a mechanically unloaded heart model / 中国应用生理学杂志

<p><b>AIM</b>To investigate the relationship between the expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 and ECM accumulation in rat left ventricle in a mechanical unloaded heart model.</p><p><b>METHODS</b>12-week-old male Lewis rats were subjected to abdominal heterotopic heart transplantation to achieve pressure and volume unloading(mechanical unloading). Age and sex matched in situ heart of Lewis rats were used as control. Collagen volume fraction(CVF) was analyzed by picrosiris-red staining plus polarized microscopy. MMP-2 and -9 gelatinolytic activity were measured by gelatin-zymography. mRNA level of MMP-2, MMP-9, TIMP-1 and TIMP-2 were measured by real-time quantitative PCR. TIMP-1 and TIMP-2 protein level were measured by immunoblotting.</p><p><b>RESULTS</b>Myocardial cross-sectional area of transplanted heart was significantly reduced, and accompanied by excessive ECM deposition (CVF 5.22% +/- 1.6% vs. 2.21% +/- 0.9%, P < 0.05) compared to in situ heart. MMP-2 and MMP-9 activity were significantly increased, as well as mRNA level of MMP-2, MMP-9, TIMP-1 and TIMP-2 compared to in situ heart. TIMP-1 and TIMP-2 protein level in mechanically unloaded heart were significantly upregulated compared to in situ heart, especially for TIMP-1.</p><p><b>CONCLUSION</b>Mechanical unloading of left ventricle may lead to excessive ECM deposition, accompanied by imbalance between MMPs and TIMPs system, especially the upregulation of TIMPs.</p>