Tuberculosis: Is Revealing It Possible Under the Lens of New Technologies?

Mycobacterium is a popular pathogen that causes several illnesses, including tuberculosis, which is the oldest known infection still in existence today. A common trait of mycobacterial infections is their difficulty in receiving treatment. Especially, the complex structure is a reflection of the pathogenicity of Mycobacterium tuberculosis (Mtb) in humans, and it is still not fully understood (Moule et al.,2020). Main problem arises from their evading mechanisms from immune system and their role of quick adaptation of environmental changes and stress responses (Chandra et al.,2022). A strong immune system, extracellular survival in hypoxic and necrotic granulomas, and bacterial multiplication inside phagocytes are all necessary for tuberculosis to remain in the host (Flentie et al.,2016).These survival paths leading arrows into the issue of the present day: antibiotic resistance. Due to their structure of thick coating of waxy mycolic acids and other glycolipids that makes up the impermeable mycobacterial outer membrane slows the absorption of a variety of substances (Poulton et al.,2023).

In all these challanges and chasing manners underlying unknown property of Mtb transcriptome waiting to explain their structure and persistancy. Mtb generating different transcription output reaction. However recently developed, Simultaneous 5′ and 3′ end sequencing (SEnd-seq) allows full-length RNA identification in transcriptome of bacteria with single-nucleotide resolution (Ju et al.,2024).Unlike normally applied RNA-Seq this method providing more high resolution of transcript boundaries . The sequence components that make up an RNA transcript, including those at the 5' and 3' ends, are essentially crucial in determining the transcript’s function. But RNA-Seq while giving information about total level of RNA ; individual transcripts’ complete nucleotide composition is lost. Experimental methods that can capture the sequences of a single transcript’s 5' and 3' termini are still rare (Ju et al.,2019). This attitude is further supported by leaving the 5' and 3' ends unaligned in certain research on the stress response of Mtb applied to RNA Seq (Martini et al.,2023).

Fig. 1 :Comparison of the RNA-seq and SEnd-seq ; determination of the intensity ranges starting from Transcriptional start site (TSS) (Ju et al.,2024)

However, SEnd-seq defines distinct transcription units and adds new transcription start and termination sites to the database by capturing 5’-3’ correlated transcripts of Mtb individually. Total RNA profiling refers that Mtb employs a lack of substantial transcription termination sites (TTSs), which are identified as locations where an obvious decrease in total RNA coverage in the transcriptome of the Mtb when compared with Escherichia coli. This drop off pattern resulting in a high proportion of short transcripts with 3′ ends. This technology reveals an important point that short RNAs, which are widely distributed in the Mtb transcriptome, are produced during RNA synthesis connected with paused RNA Polymerases (RNAP) which their pauses leads to early transcription termination (Vishwakarma et al.,2023) (Ju et al.,2024).

Fig. 2: Normalized SEnd-seq aligned at TSS intensities for Escherichia coli and Mycobacterium Tuberculosis (Ju et al.,024).

Additionally, Rifampicin is antibiotic that used as a common for treatment and starting to gain resistance in Tuberculosis. This resistance generally occurs due to mutations involve in RNAP (Lilic et al.,2020). Despite efforts to use molecular techniques to clarify the resistance level, conventional methods can fail to identify isolates that have mutations outside of the target region. Send-seq can provide insight into a crucial topic raised by this situation and effects of RNAPs pausing behavior (Li et al.,2021).These mutations manage to confer resistance, they may weakened the ability of compatibility in environmental circumstances. May convey reduction of the reaction to impact mechanism or proliferation rate of the bacteria. In the light of SEnd-Seq, RNAP is evident target for antitubercular drug development, rather then effecting RNAP antibiotics due to blocking behavior of transcription initiation, targeting paused Mtb RNAP guides the creation of novel drugs (Ju et al.,2024).

According the knowledge mentioned above indicates that, applying SEnd-Seq while repeating previous researches and future researches support revealing unknown properties of Mtb and may shed light on drug resistance pattern in Mycobacterium tuberculosis (Mtb) transcriptome which underlines that SEnd-Seq has an impact on creating new ways to develop new drugs.

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