The current landscape of microRNAs (miRNAs) in bacterial pneumonia: opportunities and challenges

Table 1 miRNAs involved in assisting the host in resisting pathogen infection

	Shuttle	Expression	Target	Species/Cells	Functions	References
Recognition	miR-708-5p	↑	TLR4	Human/HTP-1, U937	Enhancing the vitality of intracellular bacterial Regulating the secretion of inflammatory factors	[44]
Recognition	let-7b	↓	TLR4	Mice/T84	Promoting the release of proinflammatory cytokines Inducing excessive mucosal immune response	[45]
Defense	miR-181b	↑	LXA₄	Human/16HBE14o-, MΦs	Dampening neutrophil infiltration Reducing the release of proinflammatory mediators Limiting collateral tissue damage	[50]
	miR-148a-3p	↑	PTEN	Mice/BM	Promoting M1 macrophage activation and inflammatory factor secretion through NF-κB Enhancing the ability of macrophages to engulf and kill bacteria via ROS production	[52]
	miR-29b-2-5p	↑	UNC5C	Human/HeLa-229	Promoting the filopodia formation Increasing the bacterial capture Enhancing the bacterial invasion	[39]
	miR-29b-2-5p	↓	UNC5C	Human/HeLa-229	Favor the balanced intracellular replication to avoid premature cell death Conducing dissemination to neighboring cells	[39]
Clearance	miR-127	↑	A20	Mice/RAW264.7, AMs, BMDMs human/THP-1	Upregulating the proinflammatory cytokines and anti-bacterial molecules in macrophages Enhancing the clearance of bacteria Promoting the phosphorylation and ubiquitination of STAT3	[55]
Clearance	miR-125a-5p	↑	STAT3	Human/THP-1	Decreasing the autophagy of macrophages Improving the intracellular bactericidal survival	[56]

ISSN: 1689-1392