Association of Serum Melatonin Level with Mild Cognitive Impairment in Type 2 Diabetic Patients: A Cross-Sectional Study.

OBJECTIVES: Melatonin is an essential neuroendocrine hormone that participates in the regulation of sleep rhythm and cognitive function. This study aimed to determine serum melatonin levels with mild cognitive impairment (MCI) in patients with type 2 diabetes (T2DM). METHODS: A total of 247 T2DM patients were recruited in this retrospective study and divided into 75 subjects with MCI and 172 with normal cognition. Cognitive function was evaluated by the Montreal Cognitive Assessment (MoCA). Their blood sample was examined for the level of melatonin and other biochemical parameters. RESULTS: Melatonin concentration was decreased in MCI patients to non-MCI patients (P < 0.001). Melatonin level was negatively correlated with age (r = -0.202; P = 0.001), diabetes duration (r = -0.282; P < 0.001), serum HbA1c (r = -0.195; P = 0.002), hs-CRP (r = -0.324; P < 0.001), and TSH (r = -0.184; P = 0.004) levels and positively correlated with MoCA score, serum HDL-C (r = 0.145; P < 0.001), FT3 (r = 0.241; P < 0.001), and FT4 (r = 0.169; P = 0.008) levels. The multivariable analysis indicated that fewer years of formal education, longer diabetes duration, higher serum HbA1c, higher serum hs-CRP, and lower serum melatonin are the predisposing factors for MCI. CONCLUSION: Lower melatonin level was associated with cognitive impairment in patients with T2DM. Melatonin might serve as a potential protective molecule against cognitive dysfunction in T2DM.

OsCYCP1;1, a PHO80 homologous protein, negatively regulates phosphate starvation signaling in the roots of rice (Oryza sativa L.).

Phosphorus is one of the most essential and limiting nutrients in all living organisms, thus the organisms have evolved complicated and precise regulatory mechanisms for phosphorus acquisition, storage and homeostasis. In the budding yeast, Saccharomyces cerevisiae, the modification of PHO4 by the PHO80 and PHO85 complex is a core regulation system. However, the existence and possible functions in phosphate signaling of the homologs of the PHO80 and PHO85 components in plants has yet to be determined. Here we describe the identification of a family of seven PHO80 homologous genes in rice named OsCYCPs. Among these, the OsCYCP1;1 gene was able to partially rescue the pho80 mutant strain of yeast. The OsCYCP1;1 protein was predominantly localized in the nucleus, and was ubiquitously expressed throughout the whole plant and during the entire growth period of rice. Consistent with the negative role of PHO80 in phosphate signaling in yeast, OsCYCP1;1 expression was reduced by phosphate starvation in the roots. This reduction was dependent on PHR2, the central regulator of phosphate signaling in rice. Overexpression and suppression of the expression of OsCYCP1;1 influenced the phosphate starvation signaling response. The inducible expression of phosphate starvation inducible and phosphate transporter genes was suppressed in the OsCYCP1;1 overexpression lines and was relatively enhanced in the OsCYCP1;1 RNAi plants by phosphate starvation. Together, these results demonstrate the role of PHO80 homologs in the phosphate starvation signaling pathway in rice.