RNAseq analysis of treatment-dependent signaling changes during inflammation in a mouse cutaneous wound healing model

Georges St Laurent,Bernd Seilheimer,Denis Antonets,Ian Toma,Timothy A Mccaffrey,Maxim Ri,Dmitry Shtokalo,Myron Schultz,Jianhua Zhou,Konstantin Cesnulevicius,Michael Tackett,Tisha Jepson

doi:10.1186/s12864-021-08083-2

Abstract

BackgroundDespite proven therapeutic effects in inflammatory conditions, the specific mechanisms of phytochemical therapies are not well understood. The transcriptome effects of Traumeel (Tr14), a multicomponent natural product, and diclofenac, a non-selective cyclooxygenase (COX) inhibitor, were compared in a mouse cutaneous wound healing model to identify both known and novel pathways for the anti-inflammatory effect of plant-derived natural products.MethodsSkin samples from abraded mice were analyzed by single-molecule, amplification-free RNAseq transcript profiling at 7 points between 12 and 192 h after injury. Immediately after injury, the wounds were treated with either diclofenac, Tr14, or placebo control (n = 7 per group/time). RNAseq levels were compared between treatment and control at each time point using a systems biology approach.ResultsAt early time points (12–36 h), both control and Tr14-treated wounds showed marked increase in the inducible COX2 enzyme mRNA, while diclofenac-treated wounds did not. Tr14, in contrast, modulated lipoxygenase transcripts, especially ALOX12/15, and phospholipases involved in arachidonate metabolism. Notably, Tr14 modulated a group of cell-type specific markers, including the T cell receptor, that could be explained by an overarching effect on the type of cells that were recruited into the wound tissue.ConclusionsTr14 and diclofenac had very different effects on the COX/LOX synthetic pathway after cutaneous wounding. Tr14 allowed normal autoinduction of COX2 mRNA, but suppressed mRNA levels for key enzymes in the leukotriene synthetic pathway. Tr14 appeared to have a broad ‘phytocellular’ effect on the wound transcriptome by altering the balance of cell types present in the wound.

Highlights

Despite proven therapeutic effects in inflammatory conditions, the specific mechanisms of phytochemical therapies are not well understood
Global signature of diclofenac versus Tr14 The overall similarities and differences between the two types of therapy were evaluated by statistically identifying differentially expressed genes (DEGs) and organizing the DEGs according to Gene Ontologies to identify any systematic patterns of change as shown schematically in Fig. 1
This was mainly observed at the earlier time points of 12–36 h post-injury, where diclofenac altered as much as 10 times as many transcripts as Tr14 (36 h, 1840 vs 162 DEG)

Summary

Introduction

Despite proven therapeutic effects in inflammatory conditions, the specific mechanisms of phytochemical therapies are not well understood. The transcriptome effects of Traumeel (Tr14), a multicomponent natural product, and diclofenac, a non-selective cyclooxygenase (COX) inhibitor, were compared in a mouse cutaneous wound healing model to identify both known and novel pathways for the anti-inflammatory effect of plant-derived natural products. The complex physiological events that comprise the acute wound healing process may be central to understanding the biological mechanisms of chronic disease. Tissue injury and healing mechanisms share remarkable similarities in different organs [1]. Transcriptome-based studies have revealed inflammatory molecular signatures in many diseases, and precisely defined many of the inflammatory events that dominate the early stages of tissue repair [3]. The discovery of the resolvins and their actions within the inflammation system have suggested that injury “resolution” is a defining event between “acute” and “chronic” inflammation [4, 5]

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Results

Discussion

Conclusion