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Journal of Clinical and
Translational Research miRNA in pneumonia and pulmonary fibrosis

practitioners in improving treatment approaches and et al. highlighted the importance of miRNAs in controlling
researchers in developing novel therapeutic strategies. post-transcriptional gene silencing in an S-S manner. They
highlight the vast network of regulatory RNAs formed by
2. Evidence from current literature the miRNAs with multiple targets, which enables flexible

Randomized controlled trials comparing commonly used control of mRNA expression, especially in the mammalian
antibiotics for pneumococci infections with placebo or nervous system. 17
other classes of antibiotics in children under 18 years with Precursor miRNAs are processed in the nucleus and
community-acquired LRTI secondary to pneumococci cytoplasm by the endoribonucleases Drosha and Dicer.
have demonstrated the effectiveness of antibiotics in The modulation of mature miRNA levels is essential for
1
treating pediatric LRTI. Although atypical pneumonia has physiological processes such as development, differentiation,
been known for more than a century, its main causative and disease pathogenesis. Post-transcriptional mechanisms
pathogens are generally Chlamydia pneumoniae, M. include both cis-acting sequences in precursor miRNAs
pneumoniae, and L. pneumophila. The atypical pathogens and trans-acting factors that interact with these
are estimated to account for 22% of pneumonia cases precursors, affecting their processing. RNA-binding
worldwide, with diagnosis largely dependent on laboratory- proteins (RBPs) play the principal role in controlling the
based identification methods.Therapy with either macrolide processing of miRNAs. Recent investigations suggest that

antibiotics or fluoroquinolones is recommended, but more innate immune responses, particularly involving estrogen-
data are though further evidence is required to establish mediated signaling pathways, may contribute significantly
optimal treatment strategies. Combination therapy may be to systemic lupus erythematosus (SLE). Estrogen has been
considered in severe patients. 4 shown to lower the activation threshold of immune cells
Padilla has described IPF as a chronic liver disease and boost the expression of toll-like receptor 8 (TLR8).
characterized by interstitial fibrosis, leading to a Notably, miR-21 has been detected in exosomes derived
progressive decline in respiratory function and shortened from SLE patient serum and in vitro experiments have
life expectancy. Treatment strategies generally range from shown that pseudoexosomes can stimulate immune cells
13
disease-modifying interventions to symptomatic relief. to increase TLR8 expression.
Significant advances have been made in understanding 3. Biogenesis of miRNA
its pathogenesis, leading to the development of evidence-
based therapeutic guidelines. In October 2014, the U.S. miRNAs are typically located in the exonic or intronic
6
Food and Drug Administration approved pirfenidone and regions of protein-coding genes, as well as in intergenic
nintedanib for the treatment of IPF. These agents provide areas. Their production begins with transcription mediated
clinicians with validated therapeutic options, although by RNA polymerase II or III, resulting in a primary
their use requires careful consideration of safety profiles transcript called pri-miRNA. These pri-miRNAs usually
and monitoring. 15 have a 33-bp hairpin structure, a terminal loop, and a
flanking single-stranded sequence. They are also capped at
Lu and Rothenberg demonstrated that miRNAs – tiny,
naturally occurring RNA molecules – play critical roles in the 5’ end and polyadenylated at the 3’ end. In the nucleus,
the microprocessor complex, consisting of the ribonuclease
post-transcriptional gene regulation. In allergy research, Drosha and the RBP DGCR8, processes the pri-miRNA by
there is a growing interest in miRNAs owing to their cutting 11 base pairs from the junction of the hairpin stem
potential as biomarkers. miRNA mimics and inhibitors and single-stranded RNA. This produces a pre-miRNA,
have emerged as promising candidates for innovative which is then transported to the cytoplasm by Exportin-5,
therapeutic approaches. Advanced technological tools have a protein that depends on Ran-GTP. In the cytoplasm, the
been devised for various miRNA-related tasks, including enzyme Dicer further processes the pre-miRNA by cutting
isolation, quantification, profiling, target identification, near the terminal loop to generate the mature miRNA
and manipulation of mRNA levels in both laboratory and its complementary strand (miRNA*) acting as the
settings and within living organisms. 8
passenger strand. Other associated proteins, such as HIV-1
miRNAs play a major role in cellular communication TAR RNA-binding protein (TRBP) and protein activator of
by binding to complementary sequences in mRNA, PKR kinase (PACT), enhance the stability and processing
leading to the suppression of protein synthesis. However, efficiency of Dicer. In plants such as Arabidopsis, miRNA
their function is more complex than simply turning maturation also proceeds in a stepwise fashion, primarily
genes on or off. miRNAs act as post-transcriptional through the action of Dicer-like 1 (DCL1). Other Dicer-
10
regulators, playing pleiotropic roles in various biological like proteins (DCL2, DCL3, and DCL4) contribute to the
functions and diseases, including cancer. Catalanotto generation of miRNAs of differing lengths. 18
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Volume 11 Issue 2 (2025) 30 doi: 10.36922/JCTR025080009