Cardioprotective effects of Talinum paniculatum (Jacq.) Gaertn. in doxorubicin-induced cardiotoxicity in hypertensive rats

A simplified herbal decoction attenuates myocardial infarction by regulating macrophage metabolic reprogramming and phenotypic differentiation via modulation of the HIF-1α/PDK1 axis

BACKGROUND

Myocardial infarction (MI) poses a global public health challenge, often associated with elevated mortality rates and a grim prognosis. A crucial aspect of the inflammatory injury and healing process post-MI involves the dynamic differentiation of macrophages. A promising strategy to alleviate myocardial damage after MI is by modulating the inflammatory response and orchestrating the shift from pro-inflammatory (M1) to anti-inflammatory (M2) macrophages, aiming to achieve a reduced M1/M2 ratio. Nuanxinkang (NXK), a simplified herbal decoction, has demonstrated noteworthy cardioprotective, inflammation-regulating, and myocardial energy metabolism-regulating properties.

METHODS

In this study, we constructed an MI model by ligating coronary arteries to investigate the efficacy of NXK in improving ventricular remodeling and cardiac function. Mice were administered NXK (1.65 g/kg/d) or an equivalent volume of regular saline via gavage for 28 consecutive days, commencing the day after surgery. Then, we conducted echocardiography to assess the cardiac function, Masson staining to illustrate the extent of myocardial fibrosis, TUNEL staining to reveal myocardial apoptosis, and flow cytometry to analyze the polarization of M1 and M2 macrophages in the hearts. Besides, a lipopolysaccharide (LPS)-induced pro-inflammatory macrophage (M1) polarization model was implemented in RAW264.7 cells to elucidate the underlying mechanism of NXK in regulating macrophage polarization. RAW264.7 cells were pre-treated with or without NXK-containing serum. Oxidative stress was detected by MitoSox staining, followed by Seahorse energy metabolism assay to evaluate alterations in mitochondrial metabolic patterns and ATP production. Both In vivo and in vitro, HIF-1α and PDK1 were detected by fluorescent quantitative PCR and Western blotting.

RESULTS

In vivo, MI mice exhibited a decline in cardiac function, adverse ventricular remodeling, and an increase in glycolysis, coupled with M1-dominant polarization mediated by the HIF-1α/PDK1 axis. Notably, robust responses were evident with high-dose NXK treatment (1.65 g/kg/day), leading to a significant enhancement in cardiac function, inhibition of cardiac remodeling, and partial suppression of macrophage glycolysis and the inflammatory phenotype in MI mice. This effect was achieved through the modulation of the HIF-1α/PDK1 axis. In vitro, elevated levels of mitochondrial ROS production and glycolysis were observed in LPS-induced macrophages. Conversely, treatment with NXK notably reduced the oxidative stress damage induced by LPS and enhanced oxidative phosphorylation (OXPHOS). Furthermore, NXK demonstrated the ability to modify the energy metabolism and inflammatory characteristics of macrophages by modulating the HIF-1α/PDK1 axis. The influence of NXK on this axis was partially counteracted by the HIF-1α agonist DMOG. And NXK downregulated PDK1 expression, curtailed glycolysis, and reversed LPS-induced M1 polarization in macrophages, similar to the PDK1 inhibitor DCA.

CONCLUSION

In conclusion, NXK protects against MI-induced cardiac remodeling by inducing metabolic reprogramming and phenotypic differentiation of macrophages, achieved through the modulation of the HIF-1α/PDK1 axis. This provides a novel and promising strategy for the treatment of MI.

Cardiorenal damages in mice at early phase after intervention induced by angiotensin II, nephrectomy, and salt intake

The interconnection of heart performance and kidney function plays an important role for maintaining homeostasis through a variety of physiological crosstalk between these organs. It has been suggested that acute or chronic dysfunction in one organ causes dysregulation in another one, like patients with cardiorenal syndrome. Despite its growing recognition as global health issues, still little is known on pathophysiological evaluation between the two organs. Previously, we established a preclinical murine model with cardiac hypertrophy and fibrosis, and impaired kidney function with renal enlargement and increased urinary albumin levels induced by co-treatment with vasopressor angiotensin II (A), unilateral nephrectomy (N), and salt loading (S) (defined as ANS treatment) for 4 weeks. However, how both tissues, heart and kidney, are initially affected by ANS treatment during the progression of tissue damages remains to be determined. Here, at one week after ANS treatment, we found that cardiac function in ANS-treated mice (ANS mice) are sustained despite hypertrophy. On the other hand, kidney dysfunction is evident in ANS mice, associated with high blood pressure, enlarged glomeruli, increased levels of urinary albumin and urinary neutrophil gelatinase-associated lipocalin, and reduced creatinine clearance. Our results suggest that cardiorenal tissues become damaged at one week after ANS treatment and that ANS mice are useful as a model causing transition from early to late-stage damages of cardiorenal tissues.

Boesenbergia rotunda displayed anti-inflammatory, antioxidant and anti-apoptotic efficacy in doxorubicin-induced cardiotoxicity in rats

This study evaluated the cardioprotective properties of Boesenbergia rotunda extract (BrE) against doxorubicin (DOX) induced cardiotoxicity. Rats received oral gavage of BrE for 28 days and DOX (5 mg/kg/week for 3 weeks). Thereafter the animals were sacrificed, blood and cardiac samples were collected for biochemical, histological and immunohistochemical analyses. The results indicated that BrE attenuated DOX triggered body and cardiac weight loss and prevented against cardiac injury by mitigating histopathological alterations in cardiac tissues as well as serum cardiac function enzymes. BrE significantly reduced serum levels of aspartate transaminase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), troponin T (TnT) and creatine kinase-MB (CK-MB) in DOX-treated rats. Furthermore, BrE alleviated cardiotoxicity by reducing DOX instigated oxidative stress and potentiating the level of glutathione, as well as the activities superoxide dismutase and catalase in cardiac tissues. In addition, BrE significantly decreased the characteristic indices of DOX-induced cardiac inflammation and apoptosis. Immuno-histochemical analysis revealed that BrE decreased the stain intensity of p53 and myeloperoxidase (MPO) proteins compared to the DXB alone group. In conclusion, our results indicated that BrE modulated oxidative stress, inflammation and apoptosis to attenuate DOX-induced cardiac damage.

A newly identified β-amyrin synthase gene hypothetically involved in oleanane-saponin biosynthesis from Talinum paniculatum (Jacq.) Gaertn

Talinum paniculatum or Javanese ginseng in Indonesia is a plant widely used as a traditional medicine. The genus Talinum produces oleanane-type saponins, such as talinumoside I. The first aim of this study was to isolate the probable gene encoding β-amyrin synthase (bAS), a key enzyme involved in the cyclization of 2,3-oxidosqualene producing the backbone of the oleanane-type saponin β-amyrin and characterize the gene sequence and the predicted protein sequence using in silico approach. The second aim was to analyze the correlation between the TpbAS gene expression level and saponin production in various plant organs. Thus, TpbAS was isolated using degenerate primers and PCR 5'/3'-Rapid Amplification of cDNA Ends (RACE), then the gene sequence and the predicted protein were in silico analyzed using various programs. TpbAS expression level was analyzed using reverse transcriptase PCR (RT-PCR), and saponin content was measured using a spectrophotometer. The results showed that the full-length TpbAS gene consists of 2298 base pairs encoding for a 765-amino acid protein. From in silico study, the (GA)n sequence was identified in the 5'-untranslated regions and predicted to be a candidate of the gene expression modulator. In addition, functional RNA motifs and sites analysis predicted the presence of exon splicing enhancers and silencers within the coding sequence and miRNA target sites candidate. Amino acid sequence analysis showed DCTAE, QW, and WCYCR motifs that were conserved in all classes of oxidosqualene cyclase enzymes. Phylogenetic tree analysis showed that TpbAS is closely related to other plant oxidosqualene cyclase groups. Analysis of TpbAS expression and saponin content indicated that saponin is mainly synthesized and accumulated in the leaves. Taken together, these findings will assist in increasing the saponin content through a metabolic engineering approach.