A review on research progress of transketolase / 神经科学通报·英文版

Transketolase (TK), a thiamine diphosphate (ThDP)-dependent enzyme, catalyzes several key reactions of non-oxidative branch of pentose phosphate pathway. TK is a homodimer with two active sites that locate at the interface between the contacting monomers. Both ThDP and bivalent cations are strictly needed for TK activation, just like that for all ThDP-dependent enzymes. TK exists in all organisms that have been investigated. Up to now, one TK gene (TKT) and two transketolase-like genes (TKTL1 and TKTL2) have been identified in human genome. TKTL1 is reported to play a pivotal role in carcinogenesis and may have important implications in the nutrition and future treatment of patients with cancer. Researchers have found TK variants and reduced activities of TK enzyme in patients with neurodegenerative diseases, diabetes, and cancer. Recent studies indicated TK as a novel role in the prevention and therapy of these diseases.

Decreased hippocampal neurogenesis is involved in cognitive dysfunction induced by thiamine deficiency / 中华神经科杂志

Objective To investigate the influence of thiamine deficiency(TD)at early pre- pathological lesion stage on cognitive function and the correlation between cognitive dysfunction and hippocampal neurogenesis.Methods TD mouse model was prepared by feeding a thiamine-depleted diet. Learning and memory functions of TD mice were tested with Y-maze.Hippoeampal neurogenesis was studied with bromodeoxyuridine(BrdU),proliferative cell nuclear antigen(PCNA),and Doublecortin(Dcx) immunohistochemical staining on the 7th(TD7),9th,14th and TD25th day.Results TD9 mice without pathological impairment and cholinergic nerve degeneration needed more times of training(22.3?2.2)in the learning test of Y maze compared with the controls(13.5?3.5).Correspondingly,the numbers of BrdU-positive ceils and the immunoreactivity of Dcx decreased significantly in the TD9 mice(19.8?0.4, 1537.2?50.2 vs 23.9?0.3,2688.9?127.9 pixels/mm~2).Thiamine re-administration reversed the declined hippocampal neurogenesis:the number of BrdU-positive cells was 23.6?1.9 and Dcx immunoreactivity was 2052.3?269.6 pixels/mm~2:the impaired learning ability was simultaneously restored,with the number of total training trial being 16.8?0.5.Conclusion The decreased hippocampal neurogenesis contributes to retarded learning ability at early pre-pathological lesion stage of TD.