A lysosome-targeting fluorescent probe to visualize endogenous and exogenous methylglyoxal in live cells and zebrafish.

The development of a lysosome-targeting fluorescent probe to visualize endogenous and exogenous methylglyoxal (MGO) in live cells has important implications for associated diseases. Herein, a lysosome-targeting fluorescent probe MGO-Naph-A was designed and synthesized to detect MGO with high selectivity. The probe contained naphthalimide as the fluorescent group, o-phenylenediamine as the MGO recognition group, and morpholine as the lysosome targeting group. This fluorescent probe could detect endogenous and exogenous MGO in living cells by precisely targeting and staining lysosomes. It could also detect MGO in living zebrafish. The results showed that the probe MGO-Naph-A has the potential to visualize MGO in lysosomes.

4,6-Disubstituted-1H-Indazole-4-Amine derivatives with immune-chemotherapy effect and in vivo antitumor activity.

Tryptophan-2,3-dioxygenase (TDO) and indoleamine-2, 3-dioxygenase 1 (IDO1) are the important tumor immune checkpoints and TDO and IDO1 inhibition may present a potential approach to activate the T cell-mediated antitumor immune response during cancer treatment. Herein, we designed and synthesized a series of nitro-aryl 1H-indazole derivatives. SARs analysis showed that the nitro-aryl at the C-4 position of 1H-indazole was beneficial for TDO inhibition and directly tumoricidal effect and the substituents at C-6 position of 1H-indazole significantly affected the activity and selectivity of IDO1/TDO. Among these derivatives, HT-28 and HT-30 demonstrated nanomolar potency and excellent selectivity against TDO with IC50 values of 0.62 µM and 0.17 µM respectively, and HT-37 showed the IDO1 and TDO dual-target inhibitory activity with IC50 values of 0.91 µM and 0.46 µM against IDO1 and TDO. Moreover, HT-28 showed the significant tumoricidal effect on six tumor cell lines, while HT-30 and HT-37 had almost no cytotoxic activity on these tumor cells. In the CT-26 allograft BALB/c mice, HT-28 had the significant in vivo antitumor activity at a lower dose. IHC staining assay indicated that HT-28 could reduce the expression of Foxp3 and enhance the expression of CD8 and TNF-α in tumor tissue. In summary, we developed a difunctional monomer with immune-chemotherapy effect to obtain the better in anti-tumor activity.

X-ray Structure-Guided Discovery of a Potent, Orally Bioavailable, Dual Human Indoleamine/Tryptophan 2,3-Dioxygenase (hIDO/hTDO) Inhibitor That Shows Activity in a Mouse Model of Parkinson's Disease.

Human indoleamine 2,3-dioxygenase 1 (hIDO1) and tryptophan 2,3-dioxygenase (hTDO) have been closely linked to the pathogenesis of Parkinson's disease (PD); nevertheless, development of dual hIDO1 and hTDO inhibitors to evaluate their potential efficacy against PD is still lacking. Here, we report biochemical, biophysical, and computational analyses revealing that 1H-indazole-4-amines inhibit both hIDO1 and hTDO by a mechanism involving direct coordination with the heme ferrous and ferric states. Crystal structure-guided optimization led to 23, which manifested IC50 values of 0.64 and 0.04 µM to hIDO1 and hTDO, respectively, and had good pharmacokinetic properties and brain penetration in mice. 23 showed efficacy against the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse motor coordination deficits, comparable to Madopar, an anti-PD medicine. Further studies revealed that different from Madopar, 23 likely has specific anti-PD mechanisms involving lowering IDO1 expression, alleviating dopaminergic neurodegeneration, reducing inflammatory cytokines and quinolinic acid in mouse brain, and increasing kynurenic acid in mouse blood.