Serelaxin Inhibits Lipopolysaccharide-induced Inflammatory Response in Cardiac Fibroblasts by Activating Peroxisome Proliferator-activated Receptor-γ and Suppressing the Nuclear Factor-Kappa B Signaling Pathway

Q: What are the key findings of this study?

Serelaxin (100 ng/mL) significantly inhibited LPS-induced IL-1β, IL-6, TNF-α, α-SMA, and collagen I/III in rat cardiac fibroblasts (P < 0.05) via PPAR-γ activation and NF-κB suppression.

Q: What is the clinical evidence from this study?

Population: LPS-induced cardiac fibroblast inflammation and fibrosis. Intervention: Serelaxin (sRLX) vs. LPS-stimulated cardiac fibroblasts without serelaxin (and with PPAR-gamma inhibitor GW9662). Primary outcome: LPS-induced inflammatory cytokine production (IL-1beta, IL-6, TNF-alpha) and fibrotic marker expression (alpha-SMA, collagen I/III) (p=<0.05).

Q: What does this research mean for the field?

Serelaxin suppresses LPS-induced inflammatory response and myofibroblast differentiation in rat cardiac fibroblasts via ligand-independent PPAR-γ activation and NF-κB pathway inhibition. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

To investigate whether serelaxin inhibits lipopolysaccharide-induced inflammatory responses in cardiac fibroblasts and to elucidate the underlying signaling pathways involved in its antifibrotic effects.

Xueping Wu; Yehui Lv; Zhihong Li; Zhifang Yang

doi:10.1097/fjc.0000000000001447

July 6, 2023Journal of Cardiovascular PharmacologyOpen Access

Serelaxin Inhibits Lipopolysaccharide-induced Inflammatory Response in Cardiac Fibroblasts by Activating Peroxisome Proliferator-activated Receptor-γ and Suppressing the Nuclear Factor-Kappa B Signaling Pathway

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Key result

Serelaxin suppresses cardiac fibroblast inflammation and fibrosis via PPAR-γ activation and NF-κB inhibition.

P<0.05

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Why the study?

Although serelaxin inhibits fibrosis, whether its antifibrotic effects are achieved by inhibiting the inflammatory response has not been clarified.

Key Points

To investigate whether serelaxin inhibits lipopolysaccharide-induced inflammatory responses in cardiac fibroblasts and to elucidate the underlying signaling pathways involved in its antifibrotic effects.
Isolated cardiac fibroblasts from adult rat hearts and stimulated them with lipopolysaccharide (LPS), serelaxin (sRLX; 1, 10, 100, and 200 ng/mL), and the PPAR-γ inhibitor GW9662 for 24 to 72 hours.
Assessed cell viability and proliferation using MTT and CCK-8 assays across 5 independent experiments performed in duplicate.
Measured inflammatory cytokine levels (IL-1β, IL-6, TNF-α, IL-10) using ELISA, and quantified mRNA and protein levels of fibrotic markers (α-SMA, collagen I/III, MMP-2, MMP-9) and signaling mediators (IκBα, p65 NF-κB, PPAR-γ) via real-time quantitative PCR and western blotting.
Serelaxin (100 ng/mL) significantly attenuated LPS-induced proliferation (P < 0.05) and viability loss at 72 hours (P < 0.05), while significantly reducing α-SMA, collagen I, and collagen III mRNA and protein levels (P < 0.05).
Treatment with sRLX significantly suppressed LPS-stimulated secretion and mRNA expression of IL-1β, IL-6, and TNF-α, elevated IL-10 expression, and upregulated MMP-2 and MMP-9 production (P < 0.05 vs LPS).
Serelaxin strongly suppressed LPS-induced phosphorylation of NF-κB p65 and activated PPAR-γ activity without altering PPAR-γ total mRNA or protein expression; these protective effects were reversed by the PPAR-γ inhibitor GW9662 (P < 0.05).

Structured PICO

P

Population

In vitro preclinical study using primary cardiac fibroblasts isolated from adult 8-week-old Sprague-Dawley rats, stimulated with lipopolysaccharide (1 ug/mL) for 24 hours and treated for 72 hours.

I

Intervention

Serelaxin (sRLX)

C

Comparator

Lipopolysaccharide (LPS) induction without sRLX

O

Outcome

Inflammatory cytokine levels (IL-1β, IL-6, TNF-α, IL-10) and fibrosis markers (α-SMA, collagen I/III, MMP-2, MMP-9)surrogate

Main Result

p-value: p=<0.05

Serelaxin alleviates LPS-induced inflammation and fibrosis in cardiac fibroblasts by activating PPAR-γ and suppressing the NF-κB pathway.

Limitations

In vitro preclinical cell culture study in rat cardiac fibroblasts with no human clinical subjects
Did not directly verify whether serelaxin suppresses nuclear translocation of NF-p65 by immunofluorescence staining
Did not assess NF-κB transcriptional activation using a luciferase reporter gene assay
Did not test an NF-κB agonist to confirm whether it reverses the anti-inflammatory effects of serelaxin

Ask about this paper

Answers are grounded in this paper and cite their sources.

Implication

Should not change clinical practice; hypothesis-generating for serelaxin in cardiac fibroblast inflammation and fibrosis.

Abstract

Serelaxin (sRLX) has an inhibitory effect on fibrosis. However, whether the antifibrotic effects of sRLX are achieved by inhibiting the inflammatory response has not been clarified. This study aimed to investigate the role of sRLX in lipopolysaccharide (LPS)-induced inflammation in cardiac fibroblasts and elucidate the underlying mechanisms. Cardiac fibroblasts were isolated from adult rat hearts. The effect of sRLX on the inhibition of the inflammatory response after LPS induction was examined. Cell viability was measured by MMT assay. Cell proliferation was determined using the Cell Counting Kit-8. The levels of inflammatory cytokines IL-1β, IL-6, TNF-α, and IL-10 were measured using an enzyme-linked immunosorbent assay. The mRNA levels of α-smooth muscle actin (α-SMA), collagen I/III, MMP-2, MMP-9, IL-1β, IL-6, TNF-α, IL-10, IκBα, p-IκBα, p65 subunit of nuclear factor-kappa B (NF-κB), and peroxisome proliferator-activated receptor-γ (PPAR-γ) were assessed by real-time quantitative PCR. The protein levels of α-SMA, collagen I/III, MMP-2, MMP-9, IκBα, p-IκBα, p65, p-p65, and PPAR-γ were examined by western blotting. sRLX inhibited LPS-induced IL-1β, IL-6, TNF-α, α-SMA, and collagen I/III, and elevated the expression of IL-10, MMP-2, and MMP-9. Moreover, LPS-induced activation of NF-κB pathway was suppressed by sRLX treatment. Further studies showed that sRLX did not significantly increase the expression of PPAR-γ mRNA and protein, but activated PPAR-γ activity, and the PPAR-γ inhibitor GW9662 reversed the inhibitory effect of sRLX on IL-1β, IL-6, and TNF-α production. These results suggest that sRLX alleviates cardiac fibrosis by stimulating PPAR-γ through a ligand-independent mechanism that subsequently abolish the expression of NF-κB signaling pathway.

Discussion

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Cite This Study

Wu et al. (2023) studied LPS-induced cardiac fibroblast inflammation and fibrosis. Serelaxin (sRLX) vs. LPS-stimulated cardiac fibroblasts without serelaxin (and with PPAR-gamma inhibitor GW9662) was evaluated on LPS-induced inflammatory cytokine production (IL-1beta, IL-6, TNF-alpha) and fibrotic marker expression (alpha-SMA, collagen I/III) (p=<0.05). Serelaxin (100 ng/mL) significantly inhibited LPS-induced IL-1β, IL-6, TNF-α, α-SMA, and collagen I/III in rat cardiac fibroblasts (P < 0.05) via PPAR-γ activation and NF-κB suppression.

synapsesocial.com/papers/6a732203b9f617bcdd6a880c https://doi.org/10.1097/fjc.0000000000001447

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Serelaxin Inhibits Lipopolysaccharide-induced Inflammatory Response in Cardiac Fibroblasts by Activating Peroxisome Proliferator-activated Receptor-γ and Suppressing the Nuclear Factor-Kappa B Signaling Pathway

Figures

Key Points

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Serelaxin Inhibits Lipopolysaccharide-induced Inflammatory Response in Cardiac Fibroblasts by Activating Peroxisome Proliferator-activated Receptor-γ and Suppressing the Nuclear Factor-Kappa B Signaling Pathway

Figures

Key Points

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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