Elevated Serum Xanthine Oxidase and Its Correlation with Antioxidant Status in Patients with Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative movement disorder associated with a loss of dopamine neurons in the substantia nigra. The diagnosis of PD is sensitive since it shows clinical features that are common with other neurodegenerative diseases. In addition, most symptoms arise at the late stage of the disease, where most dopaminergic neurons are already damaged. Several studies reported that oxidative stress is a key modulator in the development of PD. This condition occurs due to excess reactive oxygen species (ROS) production in the cellular system and the incapability of antioxidants to neutralize it. In this study, we focused on the pathology of PD by measuring serum xanthine oxidase (XO) activity, which is an enzyme that generates ROS. Interestingly, the serum XO activity of patients with PD was markedly upregulated compared to patients with other neurological diseases (ONDs) as a control. Moreover, serum XO activity in patients with PD showed a significant correlation with the disease severity based on the Hoehn and Yahr (HY) stages. The investigation of antioxidant status also revealed that serum uric acid levels were significantly lower in the severe group (HY ≥ 3) than in the ONDs group. Together, these results suggest that XO activity may contribute to the development of PD and might potentially be a biomarker for determining disease severity in patients with PD.

Identification of double-stranded DNA in the cerebrospinal fluid of patients with acute neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system (CNS) characterized by severe myelitis and optic neuritis. Double-stranded DNA (dsDNA) is involved in the pathogenesis of various autoimmune diseases, such as systemic lupus erythematosus. However, its role in NMOSD remains unclear. In this study, the concentration of dsDNA in the cerebrospinal fluid (CSF) was quantified in 23 patients with NMOSD and 16 patients with other neurological diseases (ONDs). CSF dsDNA levels in patients with NMOSD (median: 0.03 ng/µL) were significantly higher than those in patients with ONDs (median: 0.01 ng/μl). CSF dsDNA levels showed no significant difference before and after treatment. Elevation of CSF dsDNA levels may suggest its essential role in the augmentation of CNS inflammation in patients with NMOSD.

Serum neurofilament light chain in chronic inflammatory demyelinating polyneuropathy

OBJECTIVES

Neurofilament light chain (NfL) levels have been suggested as reflecting axonal damage in various inflammatory and neurodegenerative disorders, including acquired peripheral neuropathies. We aimed to investigate if serum NfL (sNfL) levels can be a biomarker of disease activity and treatment response in patients with chronic inflammatory demyelinating polyneuropathy (CIDP).

MATERIALS AND METHODS

The sNfL levels of eleven newly diagnosed patients with CIDP were retrospectively assayed and compared with seven healthy volunteers. The levels were assayed before and after intravenous immunoglobulin treatment in patients with CIDP and were also assayed in the remission period.

RESULTS

Baseline sNfL levels in patients with CIDP before treatment were significantly higher than those in healthy controls. The levels significantly decreased overtime after one month of treatment and in remission period. There were significant negative correlations between the sNfL levels and the disease duration (the interval between the onset of the disease and the time of sampling), and weak correlations between the sNfL levels and overall neuropathy limitations scale.

CONCLUSIONS

sNfL may be a potential biomarker reflecting the disease activity in patients with CIDP.

Cerebrospinal fluid ATP as a potential biomarker in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke like episodes (MELAS)

Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is caused by defective oxidative phosphorylation in the cerebral parenchyma, cerebral blood vessels, and leptomeningeal tissue. Although increased blood and cerebrospinal fluid (CSF) lactate level has been used as a diagnostic biomarker in patients with MELAS, no biomarkers reflecting disease activity exist. Since we have developed a highly sensitive ATP assay system using luciferase luminous reaction, we examined CSF ATP in patients with MELAS and found that it negatively correlates with disease activity and that it reflects the efficacy of the treatment. CSF ATP might be a novel disease monitoring marker for MELAS.

The molecular mechanisms and gene expression profiling for shikonin-induced apoptotic and necroptotic cell death in U937 cells

Shikonin (SHK), a natural naphthoquinone derived from the Chinese medical herb Lithospermum erythrorhizon, induces both apoptosis and necroptosis in several cancer cell lines. However, the detailed molecular mechanisms involved in the initiation of cell death are still unclear. In the present study, caspase-dependent apoptosis was induced by SHK treatment at 1μM after 6h in U937 cells, with increase in DNA fragmentation, generation of intracellular reactive oxygen species (ROS), fraction of cells with low mitochondrial membrane potential (MMP), and in the expression of BH3 only proteins Noxa and tBid. Interestingly, caspase-independent cell death was also detected with SHK treatment at 10μM, observed as increase in SYTOX® Green staining and release of lactate dehydrogenase (LDH). Necrostatin-1 (Nec-1) completely inhibited the SHK-induced leakage of LDH and SYTOX® Green staining. Cell permeable exogenous glutathione (GSH) completely inhibited 1μM SHK-induced apoptosis and converted 10μM SHK-induced necroptosis to apoptosis. Gene expression profiling revealed that 353 genes were found to be significantly regulated by 1μM and 85 genes by 10μM of SHK treatment, respectively. Among these genes, the transcription factor 3 (ATF3) and DNA-damage-inducible transcript 3 (DDIT3) were highly expressed at 1μM of SHK treatment, while tumor necrosis factor (TNF) expression mainly increased at 10μM treatment. These findings provide novel information for the molecular mechanism of SHK-induced apoptosis and necroptosis.

Chemical inducers of heat shock proteins derived from medicinal plants and cytoprotective genes response

Environmental stress induces damage that activates an adaptive response in any organism. The cellular stress response is based on the induction of cytoprotective proteins, the so-called stress or heat shock proteins (HSPs). HSPs are known to function as molecular chaperones which are involved in the therapeutic approach of many diseases. Therefore in the current study we searched nontoxic chaperone inducers in chemical compounds isolated from medicinal plants. Screening of 80 compounds for their Hsp70-inducing activity in human lymphoma U937 cells was performed by western blotting. Five compounds showed significant Hsp70 up-regulation among them shikonin was most potent. Shikonin was able to induce Hsp70 at 0.1 µM after 3 h without activation of heat shock transcription factor 1 (HSF-1). It also induces significant reactive oxygen species generation. The expression level of genes responsive to shikonin was studied using global-scale microarrays and computational gene expression analysis tools. Significant increase in the nuclear factor erythroid 2-related factor 2 (Nrf2, NFEL2L2) -mediated oxidative stress response was observed that leads to the activation of HSP. The results of gene chip analysis were further confirmed by real-time qPCR assay. In short, the detailed mechanisms of Hsp70 induction by shikonin is not fully understood, Nrf2 and its target genes might be involved in the Hsp70 up-regulation in U937 cells.

Molecular mechanisms involved in the adaptive response to cadmium-induced apoptosis in human myelomonocytic lymphoma U937 cells

We examined the molecular mechanisms involved in the adaptive response to cadmium (Cd)-induced apoptosis in human myelomonocytic lymphoma U937 cells. When U937 cells were treated with 50 μM cadmium chloride (CdCl2) for 12 h, significant apoptosis occurred. This was associated with an increase in intracellular reactive oxygen species (ROS), sustained phosphorylation of JNK, activation of caspase-3, a decrease in Mcl-1 (anti-apoptotic Bcl-2 proteins), and increases in Bim, Noxa and tBid (a pro-apoptotic protein under the Bcl-2 family). No apoptosis occurred when the cells were treated with 1 μM CdCl2 for 72 h. However, pretreatment with low-dose CdCl2 dramatically altered the sensitivity of the cells to 50 μM CdCl2 with inhibition of apoptosis. Concomitantly, there were significant decreases in the generation of intracellular ROS and the activation of JNK. Pretreatment with 1 μM CdCl2 also attenuated the decrease in Mcl-1 and the increases in Bim, Noxa and tBid induced by 50 μM CdCl2. In conclusion, pretreatment with low-dose Cd inhibited apoptosis induced by high-dose Cd. The mechanism involves inhibition of intracellular ROS generation and JNK activation, and modulating the balance between the expression of Mcl-1 and its binding partners, Bim, Noxa and tBid.