Suchergebnisse

This Minireview describes the exploitation of certain enzymatically derived, readily accessible, and enantiomerically pure cis‐1,2‐dihydrocatechols as starting materials in the chemical synthesis of a range of biologically active natural products, most notably sesquiterpenoids and alkaloids. ; We thank the Chinese National Natural Science Foundation (Grant 21801094), the Australian Research Council, the Institute of Advanced Studies at the Australian National University and the Fundamental Research Funds for the Central Universities (China) (Grant 21617327) for generous financial support. SY is the grateful recipient of an Australian Government-funded PhD scholarship.

Compound ent-1 has been prepared by engaging a derivative of the enantiomerically enriched and microbially derived cis-1,2-dihydrocatechol 6 in an intramolecular Diels-Alder reaction, elaboration of the adduct so-formed to the cyclopentannulated bicyclo[2.2.2]octenone 3, and photochemical rearrangement of this to the cyclobutanone 2. By such means it has been established that 4,12-dihydroxysterpurene (1) is not the structure of the natural product isolated by Xie and co-workers from a culture broth of Stereum purpureum. ; We thank the Australian Research Council and the Institute of Advanced Studies for financial support. P.L. is the grateful recipient of a CSC Ph.D. Scholarship provided by the Government of the People's Republic of China.

Compound ent-1 has been prepared by engaging a derivative of the enantiomerically enriched and microbially derived cis-1,2-dihydrocatechol 6 in an intramolecular Diels-Alder reaction, elaboration of the adduct so-formed to the cyclopentannulated bicyclo[2.2.2]octenone 3, and photochemical rearrangement of this to the cyclobutanone 2. By such means it has been established that 4,12-dihydroxysterpurene (1) is not the structure of the natural product isolated by Xie and co-workers from a culture broth of Stereum purpureum. ; We thank the Australian Research Council and the Institute of Advanced Studies for financial support. P.L. is the grateful recipient of a CSC Ph.D. Scholarship provided by the Government of the People's Republic of China.

Hydrogenolytic cleavage of the ring-fused cyclopropane 11 using hydrogen in the presence of platinum oxide afforded the gem-dimethylated cyclohexane 12 in 99 % yield. In contrast, analogous treatment of congener 13 afforded only trace amounts of the targeted and gem-dimethylated sesquiterpene (+)-viridianol (1), the major products of reaction now being the vic-dimethylated compound 14 and the 2-fold ring-cleavage product 15. ; The authors thank the Australian Research Council and the Institute of Advanced Studies for financial support. FT and PL are the grateful recipients of funding provided by the CSC of the Government of the People's Republic of China.

A total synthesis of the title sesquiterpene 4 is described that starts with the chiral, non-racemic cis-1,2-dihydrocatechol 10 obtained through the whole-cell biotransformation of p-iodotoluene. Compound 10 is elaborated over seven steps, including Negishi cross-coupling and intramolecular Diels–Alder (IMDA) cycloaddition reactions, to ketone 7 that engages in a photochemically promoted 1,3-acyl migration and so affording cyclobutanone 6. Compound 6 was converted over further steps into the title compound 4. ; We thank the Australian Research Council and the Institute of Advanced Studies for financial support. F.T. and P.L. are the grateful recipients of funding provided by the CSC of the Government of the People's Republic of China.

Abstract
Kidney aging accelerates the progression of various acute and chronic kidney diseases and can also induce pathological changes in other organs throughout the body. Circular RNAs (circRNAs) have been demonstrated to play a vital role in aging and age-related diseases. However, biological functions and the underlying molecular mechanism of circRNAs in kidney aging remain largely unclear. Uncovering the functions of circRNAs in kidney aging and their underlying regulatory mechanisms may shed new light on the development of novel diagnostic and therapeutic strategies for human aging. Here, we report the important role of circVmn2r1 in the progression of kidney aging. We found that circVmn2r1 was one of the top expressed circRNAs in mouse kidney by RNA sequencing and was significantly upregulated in 24-month-old mouse kidney compared to 3-month-old. More importantly, we demonstrated that overexpression of circVmn2r1 promoted kidney aging in senescence-accelerated mouse prone 8 mice. Cellular assays with mouse kidney tubular epithelium (TCMK-1) cells under both gain-of-function and loss-of-function conditions demonstrated that circVmn2r1 inhibited proliferation and promoted senescence, whereas miR-223-3p counteracted these effects. Mechanistic analysis demonstrated that circVmn2r1 acted as a miR-223-3p sponge to relieve the repressive effect of miR-223-3p on its target NLRP3, which we proved could inhibit proliferation and promote senescence of TCMK-1 cells. Our results indicate that circVmn2r1 promotes kidney aging through acting as a miR-223-3p sponge, consequently upregulating NLRP3 expression, and can be a valuable diagnostic marker and an important therapeutic target for kidney aging.