Leung Kai P, D'Arpa Peter, Seth Akhil K, Geringer Matthew R, Jett Marti, Xu Wei, Hong Seok J, Galiano Robert D, Chen Tsute, Mustoe Thomas A
Microbiology Branch, US Army Dental and Trauma Research Detachment, Institute of Surgical Research, 3650 Chambers Pass, Building 3610, JBSA Fort Sam Houston, TX 78234, USA.
Systems and Integrative Biology, US Army Center for Environmental Health Research, Fort Detrick, Frederick, MD, USA.
BMC Clin Pathol. 2014 May 2;14:20. doi: 10.1186/1472-6890-14-20. eCollection 2014.
Bacterial infections of wounds impair healing and worsen scarring. We hypothesized that transcriptome analysis of wounds infected with Klebsiella pneumoniae (K.p.) or Pseudomonas aeruginosa (P.a.) would indicate host-responses associated with the worse healing of P.a.- than K.p.-infected wounds.
Wounds created on post-operative day (POD) 0 were infected during the inflammatory phase of healing on POD3 and were harvested on POD4 for microarray and transcriptome analysis. Other wounds received topical antibiotic after infection for 24 hours to promote biofilm development, and were harvested on POD6 or POD12.
Wounds infected for 24 hours, relative to uninfected wounds, elevated transcripts of immune-response functions characteristic of infiltrating leukocytes. But P.a.-infected wounds elevated many more transcripts and to higher levels than K.p.-infected wounds. Coincidently, suppressed transcripts of both wounds enriched into stress-response pathways, including EIF2 signaling; however, this was more extensive for P.a.-infected wounds, including many-fold more transcripts enriching in the 'cell death' annotation, suggesting resident cutaneous cell toxicity in response to a more damaging P.a. inflammatory milieu. The POD6 wounds were colonized with biofilm but expressed magnitudes fewer immune-response transcripts with no stress-response enrichments. However, elevated transcripts of P.a.-infected wounds were inferred to be regulated by type I interferons, similar to a network unique to P.a.-infected wounds on POD4. On POD12, transcripts that were more elevated in K.p.-infected wounds suggested healing, while transcripts more elevated in P.a.-infected wounds indicated inflammation.
An extensive inflammatory response of wounds was evident from upregulated transcripts 24 hours after infection with either bacterium, but the response was more intense for P.a.- than K.p.-infected wounds. Coincidently, more extensive down-regulated transcripts of P.a.-infected wounds indicated a stronger "integrated stress response" to the inflammatory milieu that tipped more toward cutaneous cell death. Unique to P.a.-infected wounds on POD4 and POD6 were networks inferred to be regulated by interferons, which may result from intracellular replication of P.a. These data point to specific downregulated transcripts of cells resident to the wound as well as upregulated transcripts characteristic of infiltrating leukocytes that could be useful markers of poorly healing wounds and indicators of wound-specific treatments for improving outcomes.
伤口的细菌感染会损害愈合并加重瘢痕形成。我们假设，对肺炎克雷伯菌（K.p.）或铜绿假单胞菌（P.a.）感染的伤口进行转录组分析，将揭示与P.a.感染伤口相比K.p.感染伤口愈合较差相关的宿主反应。
术后第0天（POD0）创建的伤口在愈合的炎症期（POD3）被感染，并在POD4采集样本用于微阵列和转录组分析。其他伤口在感染后接受局部抗生素治疗24小时以促进生物膜形成，并在POD6或POD12采集样本。
与未感染的伤口相比，感染24小时的伤口中，浸润白细胞特有的免疫反应功能转录本水平升高。但P.a.感染的伤口比K.p.感染的伤口有更多的转录本升高且水平更高。巧合的是，两个感染伤口中受抑制的转录本都富集到应激反应途径，包括EIF2信号通路；然而，这在P.a.感染的伤口中更广泛，包括在“细胞死亡”注释中富集的转录本多了许多倍，表明驻留皮肤细胞对更具破坏性的P.a.炎症环境产生毒性反应。POD6的伤口被生物膜定植，但表达的免疫反应转录本数量大幅减少，且没有应激反应富集。然而，P.a.感染伤口中升高的转录本被推断受I型干扰素调节，类似于POD4时P.a.感染伤口特有的一个网络。在POD12，K.p.感染伤口中升高更多的转录本表明伤口在愈合，而P.a.感染伤口中升高更多的转录本表明存在炎症。
感染两种细菌后24小时，上调的转录本显示伤口出现广泛的炎症反应，但P.a.感染的伤口反应比K.p.感染的伤口更强烈。巧合的是，P.a.感染伤口中更广泛下调的转录本表明对炎症环境有更强的“综合应激反应”，且更倾向于皮肤细胞死亡。POD4和POD6时P.a.感染伤口特有的是被推断受干扰素调节的网络，这可能是由于P.a.的细胞内复制导致的。这些数据指出了伤口驻留细胞中特定下调的转录本以及浸润白细胞特有的上调转录本，它们可能是愈合不良伤口的有用标志物以及改善伤口愈合结果的伤口特异性治疗指标。
