The functions of the influenza virus neuraminidase has been well documented but those of the mammalian neuraminidases remain less explored. Here, we characterize the role of neuraminidase 1 (NEU1) in unilateral ureteral obstruction (UUO) and folic acid (FA)-induced renal fibrosis mouse models. We find that NEU1 is significantly upregulated in the fibrotic kidneys of patients and mice. Functionally, tubular epithelial cell-specific NEU1 knockout inhibits epithelial-to-mesenchymal transition, inflammatory cytokines production, and collagen deposition in mice. Conversely, NEU1 overexpression exacerbates progressive renal fibrosis. Mechanistically, NEU1 interacts with TGFβ type I receptor ALK5 at the 160-200aa region and stabilizes ALK5 leading to SMAD2/3 activation. Salvianolic acid B, a component of Salvia miltiorrhiza, is found to strongly bind to NEU1 and effectively protect mice from renal fibrosis in a NEU1-dependent manner. Collectively, this study characterizes a promotor role for NEU1 in renal fibrosis and suggests a potential avenue of targeting NEU1 to treat kidney diseases.

Despite considerable therapeutic advances, there is still a dearth of evidence on the molecular determinants of cardiac hypertrophy that culminate in heart failure. Neuraminidases are a family of enzymes that catalyze the cleavage of terminal sialic acids from glycoproteins or glycolipids. This study sought to characterize the role of neuraminidases in pathological cardiac hypertrophy and identify pharmacological inhibitors targeting mammalian neuraminidases. Neuraminidase 1 (NEU1) was highly expressed in hypertrophic hearts of mice and rats, and this elevation was confirmed in patients with hypertrophic cardiomyopathy (n = 7) compared with healthy controls (n = 7). The increased NEU1 was mainly localized in cardiomyocytes by co-localization with cardiac troponin T. Cardiomyocyte-specific NEU1 deficiency alleviated hypertrophic phenotypes in response to transverse aortic constriction or isoproterenol hydrochloride infusion, while NEU1 overexpression exacerbated the development of cardiac hypertrophy. Mechanistically, co-immunoprecipitation coupled with mass spectrometry, chromatin immunoprecipitation, and luciferase assays demonstrated that NEU1 translocated into the nucleus and interacted with GATA4, leading to Foetal gene (Nppa and Nppb) expression. Virtual screening and experimental validation identified a novel compound C-09 from millions of compounds that showed favourable binding affinity to human NEU1 (KD = 0.38 μM) and effectively prevented the development of cardiac remodelling in cellular and animal models. Interestingly, anti-influenza drugs zanamivir and oseltamivir effectively inhibited mammalian NEU1 and showed new indications of cardio-protection. This work identifies NEU1 as a critical driver of cardiac hypertrophy and inhibition of NEU1 opens up an entirely new field of treatment for cardiovascular diseases. NEU1 promotes cardiac hypertrophy by interacting with transcriptional factor GATA4 (left), and inhibiting NEU1 by small-molecule compounds attenuates cardiac remodelling (right).

Background: Zhen-Wu-Tang (ZWT), a classic herbal formula from Treatise on Febrile and Miscellaneous Diseases, is commonly used for heart and kidney-related diseases. Despite its widespread application, research on the active components of ZWT and their mechanisms in heart–kidney cross-organ regulation remains underexplored. Aim of the study: This study aimed to elucidate the therapeutic mechanisms of ZWT in uremic cardiomyopathy (UC) focusing on its modulation of the heart–kidney inflammatory axis. Materials and methods: A UC model was established via 5/6 nephrectomy in mice, followed by 8 weeks of ZWT treatment. Functional assessments included serum creatinine, blood urea nitrogen, cardiac ejection fraction, and left ventricular metrics. Proteomic analysis using Olink technology exerts its therapeutic effects by suppressing systemic inflammation. UHPLC-Q/TOF–MS were employed to identify prototype components and blood-entering components in ZWT. Cellular experiments using a three-step co-culture system were conducted to evaluate the regulatory effects of ZWT active components on HK-2 and AC16 cells and to explore their underlying molecular mechanisms. Results: ZWT significantly improved renal and cardiac functions. Proteomics revealed ZWT suppressed pro-inflammatory cytokines TNFα, IL-6, IL-1β and chemokines. The bioactive constituents of ZWT, including benzoylaconine, paeoniflorin, and atractylenolide III, inhibited NF-κB activation, thereby reducing CCL2 synthesis and subsequent macrophage recruitment via the CCR2 axis. This attenuated systemic inflammation and cardiomyocyte injury. Conclusions: ZWT exerts therapeutic effects on UC by targeting the kidney-heart inflammatory axis and suppressing CCL2/CCR2-mediated macrophage activation. This study provides new insights into the molecular mechanisms underlying ZWT's efficacy in treating heart–kidney disorders.