The Effects of Long-Term Chaetomellic Acid A Administration on Renal Function and Oxidative Stress in a Rat Model of Renal Mass Reduction

Dissecting the Involvement of Ras GTPases in Kidney Fibrosis

Many different regulatory mechanisms of renal fibrosis are known to date, and those related to transforming growth factor-β1 (TGF-β1)-induced signaling have been studied in greater depth. However, in recent years, other signaling pathways have been identified, which contribute to the regulation of these pathological processes. Several studies by our team and others have revealed the involvement of small Ras GTPases in the regulation of the cellular processes that occur in renal fibrosis, such as the activation and proliferation of myofibroblasts or the accumulation of extracellular matrix (ECM) proteins. Intracellular signaling mediated by TGF-β1 and Ras GTPases are closely related, and this interaction also occurs during the development of renal fibrosis. In this review, we update the available in vitro and in vivo knowledge on the role of Ras and its main effectors, such as Erk and Akt, in the cellular mechanisms that occur during the regulation of kidney fibrosis (ECM synthesis, accumulation and activation of myofibroblasts, apoptosis and survival of tubular epithelial cells), as well as the therapeutic strategies for targeting the Ras pathway to intervene on the development of renal fibrosis.

Itaconic acid hybrids as potential anticancer agents

Abstract

In this paper, we report the synthesis of novel hybrids 2–14 based on itaconic acid and fluoroaniline, pyridine, indole and quinoline scaffolds. Itaconic acid is a naturally occurring compound with a Michael acceptor moiety, a key structural feature in several anticancer and antiviral drugs, responsible for the covalent binding of a drug to the cysteine residue of a specific protein. Aromatic parts of the hybrids also come from the substances reported as anticancer or antiviral agents. The synthetic route employed to access the amido-ester hybrids 2–13 used monomethyl itaconate or monomethyl itaconyl chloride and corresponding amines as the starting materials. Dimers 14 and 15 with two aminoindole or mefloquine moieties were prepared from itaconic acid and corresponding amino derivative, using standard coupling conditions (HATU/DIEA). All hybrids exerted anticancer effects in vitro against almost all the tumour cell lines that were evaluated (MCF-7, HCT 116, H460, LN-229, Capan-1, DND-41, HL-60, K-562, Z-138). Solid tumour cells were, in general, more responsive than the haematological cancer cells. The MCF-7 breast adenocarcinoma cell line appeared the most sensitive. Amido-ester 12 with chloroquine core and mefloquine homodimer 15 showed the highest activity with GI₅₀ values between 0.7 and 8.6 µM. In addition, compound 15 also exerted antiviral activity against Zika virus and Coxsackievirus B4 in low micromolar concentrations.

Graphic abstract

Electronic supplementary material

The online version of this article (10.1007/s11030-020-10147-6) contains supplementary material, which is available to authorized users.

Long-term treatment with chaethomellic acid A reduces glomerulosclerosis and arteriolosclerosis in a rat model of chronic kidney disease

The high prevalence of end-stage renal disease emphasizes the failure to provide therapies to effectively prevent and/or reverse renal fibrosis. Therefore, the aim of this study was to evaluate the effect of long-term treatment with chaethomellic acid A (CAA), which selectively blocks Ha-Ras farnesylation, on renal mass reduction-induced renal fibrosis. Male Wistar rats were sham-operated (SO) or subjected to 5/6 renal mass reduction (RMR). One week after surgery, rats were placed in four experimental groups: SO:SO rats without treatment (n=13); SO+CAA: SO rats treated with CAA (n=13); RMR:RMR rats without treatment (n=14); and RMR+CAA:RMR rats treated with CAA (n=13). CAA was intraperitoneally administered in a dose of 0.23μg/kg three times a week for six months. Renal fibrosis was evaluated by two-dimensional ultrasonography and histopathological analysis. The kidneys of the RMR animals treated with CAA showed a significantly decrease in the medullary echogenicity (p<0.05) compared with the RMR rats that received no treatment. Glomerulosclerosis and arteriolosclerosis scores were significantly lower (p<0.001) in the RMR+CAA group when compared with the RMR group. There were no significant differences in interstitial fibrosis, interstitial inflammation and tubular dilatation scores between the RMR+CAA and RMR groups. These data suggest that CAA can be a potential future drug to attenuate the progression of chronic kidney disease.