Effect of N­terminal region of human parvovirus B19­VP1 unique region on cardiac injury in naïve mice.

A unique region of human parvovirus B19 virus­VP1 (B19V­VP1u) has been linked to a variety of cardiac disorders. However, the precise role of B19V­VP1u in inducing cardiac injury remains unknown. The present study investigated the effects of B19V­VP1u and different regions of B19V­VP1u, including B19V­VP1uA (residues 1­60), B19V­VP1uB (residues 61­129), B19V­VP1uC (residues 130­195) and B19V­VP1uD (residues 196­227), on inducing cardiac injury in naïve mice by zymography, immunoblotting, H&E staining and cytokine immunoassay. A significantly higher MMP­9/MMP­2 ratio and increased levels of inflammatory cytokines, including IL­6 and IL­1ß, were detected in the left ventricles of the mice injected with B19V­non­structural protein 1 (B19V­NS1) and B19V­VP1u, accompanied by increased expression levels of phosphorylated (p­)ERK and p­P38. Significantly upregulated expression levels of atrial natriuretic peptide (ANP), heart­type fatty acid­binding protein (H­FABP) and creatine kinase isoenzyme­MB (CK­MB), which are well­known cardiac injury markers, as well as increased infiltration of lymphocytes, were detected in the left ventricles of the mice injected with B19V­VP1, B19V­NS1 and B19V­VP1u. Moreover, a significantly higher MMP­9/MMP­2 ratio and increased levels of IL­6 and IL­1ß were observed in the left ventricles of the mice injected with B19V­VP1u, B19V­VP1u­A, B19V­VP1u­B and B19V­VP1u­C, accompanied by upregulated p­ERK and p­P38 expression. Notably, significantly lower levels of IL­6 and IL­1ß were observed in the left ventricles of the mice injected with B19V­VP1uD. Furthermore, significantly increased ANP, H­FABP and CK­MB expression levels were detected in the left ventricles of the mice injected with B19V­VP1u, B19V­VP1u­A and B19V­VP1u­B, along with enhanced infiltration of lymphocytes. Significantly higher serum IL­1ß, IL­6, TNF­α and IFN­Î³ levels were also detected in the mice injected with B19V­VP1u, B19V­VP1u­A and B19V­VP1u­B. To the best of our knowledge, the findings of the present study were the first to demonstrate that the N­terminal region (residues 1­129) of B19V­VP1u induces an increase in the levels of cardiac injury markers, thus providing evidence for understanding the possible functional regions within B19V­VP1u.

Characteristic response of striatal astrocytes to dopamine depletion.

Astrocytes and astrocyte-related proteins play important roles in maintaining normal brain function, and also regulate pathological processes in brain diseases and injury. However, the role of astrocytes in the dopamine-depleted striatum remains unclear. A rat model of Parkinson's disease was therefore established by injecting 10 µL 6-hydroxydopamine (2.5 µg/µL) into the right medial forebrain bundle. Immunohistochemical staining was used to detect the immunoreactivity of glial fibrillary acidic protein (GFAP), calcium-binding protein B (S100B), and signal transducer and activator of transcription 3 (STAT3) in the striatum, and to investigate the co-expression of GFAP with S100B and STAT3. Western blot assay was used to measure the protein expression of GFAP, S100B, and STAT3 in the striatum. Results demonstrated that striatal GFAP-immunoreactive cells had an astrocytic appearance under normal conditions, but that dopamine depletion induced a reactive phenotype with obvious morphological changes. The normal striatum also contained S100B and STAT3 expression. S100B-immunoreactive cells were uniform in the striatum, with round bodies and sparse, thin processes. STAT3-immunoreactive cells presented round cell bodies with sparse processes, or were darkly stained with a large cell body. Dopamine deprivation induced by 6-hydroxydopamine significantly enhanced the immunohistochemical positive reaction of S100B and STAT3. Normal striatal astrocytes expressed both S100B and STAT3. Striatal dopamine deprivation increased the number of GFAP/S100B and GFAP/STAT3 double-labeled cells, and increased the protein levels of GFAP, S100B, and STAT3. The present results suggest that morphological changes in astrocytes and changes in expression levels of astrocyte-related proteins are involved in the pathological process of striatal dopamine depletion. The study was approved by Animal Care and Use Committee of Sun Yat-sen University, China (Zhongshan Medical Ethics 2014 No. 23) on September 22, 2014.