Formation Of ADTIQ And Its Possible Role In The Relation Between Diabetes Mellitus And Parkinson’s Disease

Diabetes(diabetes mellitus, DM) and Parkinson’s diseases(PD) are two worldwide common chronic diseases. Recent studies have shown that diabetes is significantly associated with an increased risk of developing PD, particularly in young-onset Parkinson’s disease. Number of clinical studies suggested a link between type 2 diabetes and Parkinson’s disease(PD). Moreover, previous studies reported that more than 50% of PD patients exhibit abnormal glucose tolerance or diabetes. In 2010, Morris found that type 2 diabetes caused the DA neurons damage and the decreased of secretion of striatal DA could due to iron deposition in substantia nigra neurons and led to oxidative stress. However, the underlying molecular mechanisms responsible for the association between diabetes and PD are still unknown.1-acetyl-6, 7-dihydroxy-1, 2, 3, 4-tetrahydro-isoquinoline(ADTIQ), a dopamine(DA)-derived tetrahydroisoquinolines(TIQs), was discovered in frozen human brain tissues affected with Parkinson’s disease. It is one of catecholamine isoquinolines(CAIQs) compound and its structure is similar to 1-methyl-4–phenyl-1, 2, 3, 6-tetrahydropyridine(MPTP) which is associated with Parkinson’s disease(PD). It was formatted by dopamine and methylglyoxal that is a byproduct of glycolysis. Methylglyoxal is known to be a toxic compound under pathophysiological conditions in diabetes. It suggested that ADTIQ could be related to Diabetes-Parkinson’s disease. In our study, we do some research about ADTIQ in the relation of diabetes and Parkinson’s disease.Here, the Pictet–Spengler reaction was employed to synthesize ADTIQ. We were able to optimize reaction conditions. Therefore, we decided to synthesize ADTIQ from dopamine and methylglyoxal in trifluoroacetic acid buffer at 37 °C for 24 h. we used an F5-SH semi-preparative liquid column to purify ADTIQ using 20%(v/v) methanol in aqueous ammonium formate(pH 3) as the mobile phase to prevent oxidation of ADTIQ. The product was freeze-dried and identified using high-performance liquid chromatography electrospray triple quadrupole mass spectrometry(HPLC-ESI-QQQ(MS/MS)), 1H NMR and infrared spectroscopy. Therefore, the quantitation of ADTIQ could play an important role in diagnosis of diabetic-Parkinson’s disease. Herein, a sensitive and precise method was established to quantify ADTIQ by LC/MS/MS with multiple reactions monitoring(MRM) mode.Increased levels of ADTIQ and methylglyoxal were detected in the striatum of diabetic rats and in the SH-SY5 Y dopaminergic cell line cultured in the presence of high glucose concentrations. As well as, in our research, SH-SY5 Y neuroblastoma cells were exposed to 50 and 200 mmol / L glucose, high glucose lead to the damage of mitochondrial integrity and reactive oxygen species which promotes the apoptosis. Neuronal dysfunction was found in the SNc and striatum of diabetic rats by Nissl staining of neurons. While, the decreased of dopamine was detected in the Plasma of diabetic rats and SH-SY5 Y dopaminergic cell which exposed to glucose. The results showed hyperglycemia lead to dopamine neuron dysfunction in diabetes. The increased levels of ADTIQ could be a reason of dopamine neuron dysfunction in diabetes. ADTIQ level could be related to hyperglycemia and methylglyoxal.And then, we studied the influence on SH-SY5 Y cells with ADTIQ and the mechanism of injury. The results showed that ADTIQ could activate Bax, decrease anti-apoptosis protein Bcl-2, and caused the release of Cytochrome C. An increase of Caspase-3 could damage mitochondrial to lead to cells’ apoptosis. In conclusion, ADTIQ could lead to dopamine neuron’s apoptosis by mitochondrial damage. To prove a relationship between ADTIQ and PD, we demonstrate the detection of ADTIQ in brain samples of control mice and transgenic PD mice, which express either human wild-type(wt) or mutated(A53T, or A30P) forms of α-synuclein(α-Syn). The levels of α-synuclein and the behaviors of the transgenic mice are shown as Parkinson’s disease(PD), respectively. Compare with the control mice, the concentration of ADTIQ increased significantly in brain samples obtained from transgenic mice expressing A53 T or A30 P α-synuclein, but not in the mice expressing wild-type. Accumulating evidence demonstrates that mice bearing mutated α-synucleins show enhanced tendencies to accumulate α-synuclein and are more susceptible to oxidative stress than wild-type in vivo and vitro. We suggest, therefore, that the differences in ADTIQ levels between mice expressing wild-type human α-Syn, A53 T, and A30 P α-synucleins correlate with characteristic pathological features of α-synuclein mutations.Semicarbazide sensitive amine oxidases(SSAO) exist as a homodimeric glycoprotein; act as a monoamine oxidase, deaminating primary amines to produce corresponding aldehyde, ammonia and hydrogen peroxide. The detrimental role of SSAO in diabetes mellitus is reported with several vascular changes suggesting that SSAO could play a vital role in blood vessels; hence in the pathogenesis of diabetes. In order to study the SSAO in vitro physiological model two cell lines were generated and characterized, i.e., human embryonic kidney cell(HEK) and human umbilical arterial endothelial cell(HUAEC) transfected with the complete length of human SSAO gene. Furthermore, we present the comparative SSAO expression study in human umbilical tissue, previously developed prokaryotic SSAO expression model, i.e., E. coli BL21 and models obtained in this study, i.e., HEK and HUAEC, in order to describe its best expression model.This study provides a new train of thought to found that the formation of ADTIQ associated with the link between diabetes and Parkinson’s disease.