Novel N-substituted aminobenzamide scaffold derivatives targeting the dipeptidyl peptidase-IV enzyme

Identification and functional characterization of the dirigent gene family in Phryma leptostachya and the contribution of PlDIR1 in lignan biosynthesis

BACKGROUND

Furofuran lignans, the main insecticidal ingredient in Phryma leptostachya, exhibit excellent controlling efficacy against a variety of pests. During the biosynthesis of furofuran lignans, Dirigent proteins (DIRs) are thought to be dominant in the stereoselective coupling of coniferyl alcohol to form ( ±)-pinoresinol. There are DIR family members in almost every vascular plant, but members of DIRs in P. leptostachya are unknown. To identify the PlDIR genes and elucidate their functions in lignan biosynthesis, this study performed transcriptome-wide analysis and characterized the catalytic activity of the PlDIR1 protein.

RESULTS

Fifteen full-length unique PlDIR genes were identified in P. leptostachya. A phylogenetic analysis of the PlDIRs classified them into four subfamilies (DIR-a, DIR-b/d, DIR-e, and DIR-g), and 12 conserved motifs were found among them. In tissue-specific expression analysis, except for PlDIR7, which displayed the highest transcript abundance in seeds, the other PlDIRs showed preferential expression in roots, leaves, and stems. Furthermore, the treatments with signaling molecules demonstrated that PlDIRs could be significantly induced by methyl jasmonate (MeJA), salicylic acid (SA), and ethylene (ETH), both in the roots and leaves of P. leptostachya. In examining the tertiary structure of the protein and the critical amino acids, it was found that PlDIR1, one of the DIR-a subfamily members, might be involved in the region- and stereo-selectivity of the phenoxy radical. Accordingly, LC-MS/MS analysis demonstrated the catalytic activity of recombinant PlDIR1 protein from Escherichia coli to direct coniferyl alcohol coupling into ( +)-pinoresinol. The active sites and hydrogen bonds of the interaction between PlDIR1 and bis-quinone methide (bisQM), the intermediate in ( +)-pinoresinol formation, were analyzed by molecular docking. As a result, 18 active sites and 4 hydrogen bonds (Asp-42, Ala-113, Leu-138, Arg-143) were discovered in the PlDIR1-bisQM complex. Moreover, correlation analysis indicated that the expression profile of PlDIR1 was closely connected with lignan accumulations after SA treatment.

CONCLUSIONS

The results of this study will provide useful clues for uncovering P. leptostachya's lignan biosynthesis pathway as well as facilitate further studies on the DIR family.

Emergence of promising novel DPP-4 inhibitory heterocycles as anti-diabetic agents: A review

Diabetes has turned out to be an epidemic in the recent years all over the world, and today it has become a burden on the healthcare system. Over the years, with technological advancements, different classes of antidiabetic medications have emerged, like sulfonylureas, biguanides, alpha-glucosidase inhibitors, and thiazolidinediones, but these are often loaded with serious aftermaths like hypoglycemia, weight gain, cardiovascular and renal issues. Dipeptidyl peptidase-4 (DPP-4) inhibition is an exciting and new approach in the treatment of type-2 diabetes. DPP-4 inhibitors or "gliptins" are weight neutral, pose lesser risk of hypoglycemia, and provide a long-term post-meal glycemic control. In this review, an attempt has been made to investigate novel potential compounds that can be added to the existing list of anti-diabetic drugs.

Potassium-3-beta-hydroxy-20-oxopregn-5-en-17-alpha-yl sulfate: a novel inhibitor of 78 kDa glucose-regulated protein

BACKGROUND

Previous studies have shown the central role of 78 kDa glucose-regulated protein (GRP78) in colorectal cancer (CRC) survival and chemoresistance. In the present study, we aimed to design a GRP78 inhibitor and test its potential to inhibit CRC cells growth.

MATERIALS AND METHODS

Computer-aided drug design was used to establish novel compounds as potential inhibitors of GRP78. Discovery Studio 3.5 software was used to evaluate a series of designed compounds and assess their mode of binding to the active site of the protein. The cytotoxicity of the designed compounds was evaluated using the MTT assay and the propidium iodide method. The effect of the inhibitor on the expression of GRP78 was evaluated by immunoblotting.

RESULTS

Among the designed compounds, only potassium-3-beta-hydroxy-20-oxopregn-5-en-17-alpha-yl sulfate (PHOS) has a potential to inhibit the growth of CRC cells. Inhibition of cellular growth was largely attributed to downregulation of GRP78 and induction of apoptotic cell death.

CONCLUSION

These results introduce PHOS as a promising GRP78 inhibitor that could be used in future studies as a combination with chemotherapy in the treatment of CRC patients. Our ongoing studies aim to characterize PHOS safety profile as well as its mechanism of action.