Paromomycin

Interaction Dynamics with 16S Ribosomal RNA (rRNA) and 30S Ribosomal Subunit

This compound binds specifically to the 16S rRNA component of the 30S ribosomal subunit. Its binding site is located within an internal loop of the decoding site, predominantly interacting with helix 44 (h44) mdpi.comnih.gov. Key nucleotides involved in this interaction are A1492 and A1493 within h44 mdpi.comasm.org. Upon this compound binding, these nucleotides "flip out" in a manner similar to their conformation during cognate tRNA and mRNA binding asm.org. This conformational change in the decoding site is central to this compound's effects on translation nih.gov.

The binding of this compound to h44 also induces structural rearrangements in the 30S subunit. It can cause a rotation of the head and spur towards the shoulder of the 30S subunit, leading to a "closed form" asm.org. This conformational change is also observed upon cognate tRNA binding asm.org. Furthermore, this compound binding in the decoding center of the 70S ribosome can elicit moderate structural rearrangements in the A-site tRNA-binding pocket, potentially influencing translation accuracy pnas.org.

This compound also interacts extensively with the intersubunit region of the ribosome, providing additional contacts between the small and large subunits, particularly in the vicinity of bridge B2c, formed by h24 of the small subunit and H66 of the large subunit pnas.org. Binding to Helix 69 (H69) of the large ribosomal subunit, which forms a critical intersubunit bridge (B2a) contacting the h44 decoding site, can alter the conformation of bridge B2 and the process of small subunit rotation relative to the large subunit pnas.org.

This compound can also inhibit the antiassociation activity of initiation factor 3 (IF3), a factor important for the disassembly of post-termination ribosomal complexes asm.org. This inhibition stems from this compound strengthening the interaction between ribosomal subunits, even inducing subunit association at low Mg2+ concentrations asm.org. The stabilization of 70S ribosomes by this compound may contribute to its inhibitory effects on translocation and ribosome recycling asm.org.

Induction of mRNA Misreading and Perturbation of Translational Fidelity

A well-known effect of this compound is its ability to induce miscoding during protein synthesis asm.orgdrugbank.com. By binding to the decoding site and causing the flipping out of A1492 and A1493, this compound stabilizes the mispairing of codon-anticodon interactions mdpi.com. These nucleotides are normally involved in detecting correct Watson-Crick pairing between the codon and anticodon wikipedia.org. The altered conformation facilitates high-affinity binding between the 16S rRNA and rings I and II of the antibiotic, contributing to codon misreading and mistranslation of mRNA nih.gov.

This misreading leads to the incorporation of incorrect amino acids into the growing polypeptide chain, resulting in the production of nonfunctional or toxic proteins patsnap.com. Studies in cell-free systems from Saccharomyces cerevisiae have shown that this compound induces optimal mistranslation at certain concentrations, with effects declining at higher concentrations nih.gov. It can induce general misreading of mRNA and even read-through of termination codons under specific conditions nih.gov.

Translational infidelity induced by aminoglycosides like this compound disturbs the ribosome-decoding center, promoting misincorporation of amino acids at near-cognate codons nih.gov. While misincorporation can potentially rescue improperly truncated proteins, it also increases the risk of errors and the production of misfolded proteins nih.gov.

Modulation of Protein Elongation Rates and Ribosomal Translocation Processes

Beyond miscoding, this compound also affects the elongation phase of protein synthesis and ribosomal translocation. Translocation is the process where the ribosome moves along the mRNA by one codon after the addition of each amino acid, a process catalyzed by elongation factor G (EF-G) patsnap.comnih.gov.

This compound can inhibit translocation asm.orgpatsnap.comnih.gov. This inhibition is attributed, in part, to the stabilization of tRNA binding in the A site nih.govmpg.de. By stabilizing the A-tRNA, this compound increases the energy barrier for the ribosome to translocate nih.gov. It can also disrupt ribosomal rotation, a conformational change that accompanies nearly every aspect of translation, including translocation pnas.orgnih.gov.

However, the exact mechanism of this compound's effect on translocation and ribosome recycling is still being elucidated asm.org. Some studies suggest that while this compound can slow down translation elongation, it may not cause a complete inhibition of translocation in live bacterial cells, but rather a slowing of the process pnas.org. Single-molecule studies have reported a two- to six-fold slowdown of translocation rates for this compound or lengthening of the rotated ribosome state pnas.org.

Influence of Ribosomal Proteins (e.g., S12) on this compound Activity and Fidelity Control

Ribosomal proteins play a crucial role in the fidelity of translation and can influence the activity of aminoglycosides like this compound. Ribosomal protein S12, located near the A-site of the 30S subunit, is a key contributor to mRNA decoding fidelity nih.govplos.org. S12 is involved in distinguishing between cognate and near-cognate tRNA species and promoting conformational rearrangements in the small subunit, referred to as "closure" nih.govresearchgate.net.

Mutations in the gene encoding S12 (rpsL) can lead to altered translational accuracy and resistance to aminoglycosides plos.organnualreviews.org. Some S12 mutations confer a "restrictive" or hyper-accurate phenotype, increasing fidelity and reducing misreading nih.govplos.orgresearchgate.net. Interestingly, certain S12 variants have shown substantial resistance to the miscoding effects of this compound nih.govresearchgate.net.

Research suggests that S12 mutations that are refractory to this compound's miscoding effect may be compensated by a probable second, lower-affinity binding site for this compound in the 16S rRNA nih.gov. This secondary site is thought to facilitate the closure of the small subunit, counteracting the defects associated with the S12 mutations nih.gov. This highlights the complex interplay between ribosomal proteins, rRNA, and antibiotic binding in controlling translational fidelity.

Differential Effects on Leishmania Ribosomes and Host Cell Selectivity

This compound has demonstrated efficacy against various protozoal infections, including leishmaniasis wikipedia.orgpatsnap.commdpi.com. Studies have investigated the basis for its selective toxicity towards Leishmania parasites compared to mammalian cells.

Research has shown that this compound strongly inhibits protein synthesis in Leishmania mexicana promastigotes asm.orgnih.gov. In cell-free systems, this compound significantly decreases both polypeptide synthesis and the accuracy of translation when using ribosomal particles from Leishmania asm.orgnih.gov. In contrast, when ribosomes from mammalian cells are used, polyphenylalanine synthesis is only slightly reduced, and translation misreading remains largely unaltered asm.orgnih.gov.

Surface plasmon resonance analysis has revealed a strong binding of this compound to the ribosomal decoding site of the parasite, with practically no interaction observed with the mammalian cell counterpart asm.orgnih.gov. This differential binding affinity to ribosomal RNA appears to be a key factor explaining the selective action of this compound on Leishmania protein synthesis and proliferation asm.orgnih.gov.

The selective targeting of Leishmania ribosomes by this compound, despite similarities between prokaryotic and eukaryotic ribosomes, suggests structural differences in the ribosomal decoding site or surrounding regions that allow for preferential binding of the antibiotic to the parasite ribosome oup.com. Cryoelectron microscopy studies have shown this compound binding to the Leishmania 91S subunit, disrupting tRNA recruitment plos.org.

The observed differential effects on translation processes between Leishmania and mammalian hosts provide a molecular basis for the therapeutic efficiency of this compound as an antileishmaniasis agent asm.orgnih.gov.

Here is a summary of research findings on this compound's effects on translation fidelity in Leishmania and mammalian cell-free systems:

Note: Data is illustrative based on descriptions in the provided text snippets and may not represent exact quantitative values from a single study.

Disruption of Mitochondrial Membrane Potential in Leishmania Species

In Leishmania species, this compound is understood to affect the parasite's energetic metabolism, partly through the disruption of the mitochondrial membrane potential. researchgate.netplos.orgresearchgate.net This disruption contributes to respiratory dysfunction within the parasite. researchgate.net Studies have shown a significant decrease in mitochondrial membrane potential after exposure to this compound, suggesting the mitochondria as a potential ultimate target of the drug. nih.govnih.govcapes.gov.br This effect on mitochondrial function is considered a key component of this compound's antileishmanial activity. researchgate.netplos.orgresearchgate.net

Inhibition of Cytoplasmic and Mitochondrial Protein Synthesis in Parasitic Organisms

A primary mechanism of action for this compound is the inhibition of protein synthesis. patsnap.commims.comresearchgate.netplos.orgresearchgate.net This occurs through binding to ribosomal RNA, specifically the 16S rRNA of the 30S ribosomal subunit in susceptible organisms, which is similar to its antibacterial effects. patsnap.comwikipedia.orgplos.orgresearchgate.net This binding interferes with the ribosome's function, leading to misreading of mRNA and the incorporation of incorrect amino acids into polypeptide chains, resulting in nonfunctional or toxic proteins. patsnap.comwikipedia.org Additionally, this compound inhibits translocation, the process by which the ribosome moves along the mRNA, further halting protein synthesis. patsnap.com

In Leishmania donovani, this compound has been shown to inhibit both cytoplasmic and mitochondrial protein synthesis. nih.govnih.govcapes.gov.br While some studies initially presented conflicting findings regarding its effect on mitochondrial protein synthesis in Leishmania, later research, including proteomic analysis of resistant strains, supports the inhibition of translational machinery, particularly ribosomal proteins, as a key aspect of this compound's action within the parasite. plos.orgplos.org The differential effects of this compound on the ribosomes of Leishmania parasites compared to mammalian cells may explain its selective toxicity. nih.govnih.gov

Exploration of Potential Anti-Cancer Mechanisms (e.g., HDAC1 inhibition, IGF1R translocation)

Studies are investigating this compound's potential as an anti-cancer agent, particularly in glioblastoma (GBM). Research suggests that this compound may exert anti-cancer effects by targeting histone deacetylase 1 (HDAC1) and influencing insulin-like growth factor 1 receptor (IGF1R) translocation. frontiersin.orgnih.govnih.govresearcher.liferesearchgate.net HDAC1 is an enzyme involved in epigenetic regulation and is often overexpressed in various cancers, contributing to tumor growth and survival. frontiersin.orgnih.govunipi.it this compound has been shown to act as an HDAC1 inhibitor, potentially reversing epigenetic modifications that promote tumor growth. frontiersin.org

Furthermore, this compound treatment has been observed to lead to a dose-dependent reduction in GBM cell viability, colony formation, and migration in vitro. frontiersin.orgnih.govnih.govresearchgate.net It has been shown to modulate SUMO1 expression and decrease IGF1R nuclear translocation, an effect that can be reversed by HDAC1 inhibitors, suggesting its involvement in SUMO1-regulated pathways. frontiersin.orgnih.govnih.gov These findings highlight this compound's potential to influence key signaling pathways involved in cancer progression by targeting HDAC1-mediated SUMOylation and affecting IGF1R localization. frontiersin.orgnih.govnih.govresearchgate.net

Interactive Data Table: Effect of this compound on Glioblastoma Cell Viability (Illustrative Example based on search results)

(Note: Specific numerical data for concentrations and viability percentages would need to be extracted from detailed research findings if available and presented in an interactive table format.)

Antiviral Activity Research (e.g., SARS-CoV-2 Spike Protein and Protease Binding)

Research is also exploring the potential antiviral activity of this compound, including against SARS-CoV-2. In silico studies have investigated this compound's ability to interact with key viral proteins, such as the spike protein (S1) and the main protease of SARS-CoV-2. nih.govresearchgate.net These studies suggest that this compound may have strong binding affinity for both of these targets. nih.govresearchgate.net The spike protein is crucial for viral entry into host cells, while the main protease is essential for viral replication. oup.comnih.govfrontiersin.orgmdpi.com

Molecular docking analysis has indicated that this compound can bind to the protease domain and the spike domain of SARS-CoV-2 with high stability. nih.govresearchgate.net This potential dual targeting of both the spike protein and the main protease suggests that this compound could be a promising candidate for further investigation as an antiviral agent against SARS-CoV-2. nih.govresearchgate.net While aminoglycosides are generally less permeable to eukaryotic cells, some research suggests their intracellular concentrations might increase during active viral infection. nih.gov

Systemic Absorption Profiles Following Varied Administration Routes (e.g., Topical vs. Oral)

This compound exhibits poor absorption following oral administration, with nearly 100% of the dose typically recovered in the stool. drugbank.commims.commims.com This limited oral bioavailability is attributed to its large molecular size and highly hydrophilic nature. nih.gov

In contrast, intramuscular (IM) administration results in rapid absorption, with peak plasma concentrations generally occurring within 1 to 2 hours after dosing. scienceopen.comsante.frnih.gov Bioavailability after IM injection is expected to be close to 100%. scienceopen.comnih.gov

Topical application of this compound can also lead to systemic absorption, although the extent may vary. Studies in mice with ulcerated cutaneous leishmaniasis lesions demonstrated detectable this compound concentrations in plasma up to 1 hour after topical gel application, suggesting systemic absorption. oup.com

Characterization of Tissue Distribution and Application of Compartmental Models

This compound is a hydrophilic compound with limited distribution to tissues. scienceopen.comnih.gov Its volume of distribution is approximately 40% of body weight. scienceopen.comnih.gov In mice, this compound showed a 2.5-fold higher volume of distribution than total body water, suggesting extensive distribution into tissues such as the liver, spleen, and pancreas, where Leishmania parasites reside. nih.gov

Pharmacokinetic data for this compound have been analyzed using compartmental models to describe its disposition in the body. Both one- and two-compartment models with first-order absorption and elimination have been tested to fit plasma concentration-time data. scienceopen.comnih.gov A one-compartment model has been found to adequately describe this compound observations in plasma. scienceopen.comnih.gov However, a 3-compartment model with a saturable compartment has also been used to characterize renal clearance processes in studies involving visceral leishmaniasis patients. nih.govoup.com

Compartmental models represent hypothetical spaces or groups of tissues where the drug distributes. patelkwan.com A one-compartment model assumes immediate and homogenous distribution throughout the body, while a two-compartment model includes a central compartment (blood and highly perfused tissues) and a peripheral compartment (poorly perfused tissues) with dynamic drug transfer between them. patelkwan.comufl.eduslideshare.net

Typical values for pharmacokinetic parameters estimated using a one-compartment model in visceral leishmaniasis patients include a clearance of 4.38 L/h and a volume of distribution of 15.6 L. scienceopen.comnih.gov

Renal Clearance Mechanisms, Including Saturable Tubular Reabsorption Processes

The main route of elimination for systemically absorbed this compound is renal excretion via glomerular filtration. scienceopen.comnih.govnih.govoup.com However, studies have reported urine recovery rates lower than 100% after a dose, suggesting that absorption might not be complete or that other elimination pathways contribute to a minor extent. mims.commims.comscienceopen.comnih.gov

Renal clearance of this compound involves glomerular filtration of the unbound fraction of the drug, as well as tubular reabsorption and potential tubular secretion processes. nih.gov this compound, like other aminoglycosides, can accumulate in the proximal tubules via megalin receptors on the apical surface. nih.gov This tubular reabsorption process is saturable and has been associated with the development of kidney injury. nih.gov

Pharmacokinetic Heterogeneity in Visceral Leishmaniasis Subpopulations (e.g., PKDL vs. VL, Pediatric vs. Adult Patients)

Significant pharmacokinetic differences have been observed between patients with post-kala-azar dermal leishmaniasis (PKDL) and visceral leishmaniasis (VL) in Eastern Africa. nih.govoup.comresearchgate.netdiva-portal.orgresearcher.life VL patients have shown a lower capacity for this compound saturable reabsorption in renal tubules compared to PKDL patients. nih.govoup.comresearchgate.netdiva-portal.orgresearcher.life This difference necessitates an adjustment when relating renal clearance to estimated glomerular filtration rate (eGFR) based on creatinine levels in VL patients. nih.govoup.comresearchgate.netdiva-portal.orgresearcher.life

Comparing PKDL to VL patients on similar regimens, this compound plasma exposures have been found to be lower in PKDL patients (0.74- to 0.87-fold) than in VL patients. nih.govoup.comresearchgate.netdiva-portal.orgresearcher.life These variations highlight the challenges of directly extrapolating dosing regimens between these two presentations of leishmaniasis. nih.govoup.comresearchgate.netdiva-portal.orgresearcher.life

Population pharmacokinetic studies have also evaluated this compound exposure in pediatric versus adult patients with visceral leishmaniasis. nih.govresearchgate.netoup.comdndi.orgoup.com Data from studies in Eastern Africa indicate that this compound exposure, as measured by the area under the concentration-time curve (AUC) at the end of treatment, was lower in pediatric patients compared to adults. nih.govresearchgate.netoup.com However, the exposures in both pediatric and adult patients in these studies were within the range observed in previous studies of adult patients from certain geographical regions. nih.govresearchgate.netoup.com

Geographical variability in this compound pharmacokinetics has also been noted. scienceopen.comnih.govoup.com Studies comparing patients from Eastern Africa and India have revealed differences in bioavailability and absorption rates, although these differences did not fully explain observed variations in treatment efficacy. scienceopen.comnih.govoup.com For instance, bioavailability was found to be higher in Kenyan and Sudanese patients (1.17 times) and Ethiopian patients (2.46 times) compared to Indian patients. scienceopen.comnih.gov Ethiopian patients also exhibited a slower absorption rate constant. scienceopen.comnih.gov

Between-subject variability in this compound pharmacokinetic parameters like clearance and volume of distribution has been identified in population studies. scienceopen.comnih.gov Covariates such as serum creatinine or eGFR, serum albumin, and time after the start of treatment have been explored for their potential influence on this compound pharmacokinetics. scienceopen.comnih.govoup.com A decrease in clearance over time has been observed, which was significantly associated with an increase in plasma neutrophils. oup.com

Below is a summary of some pharmacokinetic parameters observed in studies:

Impact of Pathological States on Drug Exposure Profiles and Clinical Outcomes

Pathological states can significantly influence the pharmacokinetic profile of this compound, subsequently affecting clinical outcomes. Studies in patients with leishmaniasis have revealed disease-specific differences in this compound pharmacokinetics between Post-Kala-Azar Dermal Leishmaniasis (PKDL) and Visceral Leishmaniasis (VL) diva-portal.orgoup.com. These variations are attributed to disease-specific differences in absorption, distribution, and elimination processes diva-portal.orgoup.com.

Renal function, which is often better preserved in PKDL patients compared to VL patients, may influence this compound clearance, as the drug is primarily excreted unchanged via glomerular filtration diva-portal.orgoup.com. Investigations have shown that VL patients exhibit a lower capacity for this compound saturable reabsorption in renal tubules compared to PKDL patients diva-portal.orgoup.com. This necessitates an adjustment when correlating renal clearance to creatinine-based estimated glomerular filtration rate in VL patients diva-portal.orgoup.com.

Comparing PKDL and VL patients receiving the same this compound regimen, plasma exposures in PKDL patients were found to be 0.74- to 0.87-fold lower than in VL patients diva-portal.orgoup.com. These observed pharmacokinetic differences between the two presentations of leishmaniasis in Eastern Africa underscore the challenges associated with directly extrapolating dosing regimens from one form to another diva-portal.orgoup.com.

Age also represents a factor influencing this compound exposure in pathological states. In a study involving VL patients, this compound exposure, measured by the area under the plasma concentration-time curve (AUC) at the end of treatment, was lower in pediatric patients compared to adults nih.govnih.gov.

Furthermore, the integrity of the gastrointestinal tract can impact this compound absorption. While generally poorly absorbed orally, absorption may be increased in individuals with impaired gastrointestinal motility or the presence of intestinal lesions or ulcerations mims.com. Following topical administration, this compound exposure has been observed to increase with multiple dosing, potentially due to drug saturation of skin tissue and increased systemic absorption, with high variability in pharmacokinetic parameters possibly reflecting the extent of tissue damage asm.org. In newborn animals, higher gastrointestinal absorption of this compound has been noted noahcompendium.co.uk.

Geographical location has also been associated with differences in this compound pharmacokinetics in VL patients. A population pharmacokinetic analysis comparing Eastern African and Indian VL patients found variations in bioavailability and steady-state AUC values between regions researchgate.net.

Alterations in Drug Accumulation and Efflux Mediated by Transport Systems (e.g., ABC Transporters)

One significant mechanism of this compound resistance involves reduced intracellular accumulation of the drug. This can occur through decreased drug uptake or increased efflux mediated by transport systems. ATP-binding cassette (ABC) transporters, a superfamily of membrane proteins, play a crucial role in actively transporting various substrates, including drugs, across cellular membranes. medtechbcn.commdpi.com In Leishmania, upregulation of ABC transporters such as MDR1 and MRPA has been observed in this compound-resistant strains, contributing to enhanced drug efflux and consequently lower intracellular drug concentrations. frontiersin.orgnih.govnih.govresearchgate.netasm.org Studies have shown that this compound-resistant Leishmania donovani parasites exhibit decreased intracellular drug accumulation, which is accompanied by increased membrane fluidity. nih.govnih.govasm.org Inhibitors of ABC transporters have been shown to increase this compound susceptibility in resistant parasites, highlighting the role of these transporters in resistance. researchgate.net

Ribosomal Mutations and Modifications at Antibiotic Binding Sites

This compound primarily targets the ribosomal RNA of the small ribosomal subunit, binding to the A-site and interfering with protein synthesis. nih.govplos.orgnoahcompendium.co.uk Mutations and modifications at these ribosomal binding sites can lead to resistance by reducing the affinity of this compound for the ribosome or altering the drug's effects on translation. In bacteria, mutations in the 16S rRNA, particularly in the A-site (e.g., at positions A1492 and A1493 in E. coli numbering), have been shown to confer resistance to aminoglycosides, including this compound. plos.orgplos.org These mutations can affect the shape and dynamics of the binding cleft, disrupting hydrogen bonds essential for this compound binding. plos.orgplos.org Ribosomal protein S12, located near the decoding center, also plays a role, and mutations in S12 can lead to this compound resistance. asm.orgnih.gov While this compound targets the bacterial small ribosomal subunit, its activity against parasites like Leishmania is thought to involve interaction with the parasite's ribosomal decoding site, although the precise target is debated and may involve both cytoplasmic and mitochondrial ribosomes. researchgate.netasm.orgplos.org Mutations in the 15S rRNA gene have been linked to this compound resistance in yeast. nih.gov

Enzymatic Inactivation Pathways of this compound

Enzymatic modification is a prevalent mechanism of aminoglycoside resistance in bacteria. nih.govegms.de This involves enzymes that catalyze the modification of the antibiotic molecule, rendering it inactive or less effective. Three main types of aminoglycoside modifying enzymes are recognized: nucleotidyltransferases, phosphotransferases, and acetyltransferases, which modify different hydroxyl or amino groups on the antibiotic. nih.gov For instance, this compound can be inactivated by aminoglycoside 3'-phosphotransferase. nih.gov In Streptomyces rimosus, the producing organism of this compound, resistance involves both a this compound acetyltransferase and a this compound phosphotransferase, and both enzymes are required for high-level resistance. csic.es While enzymatic inactivation is a well-established mechanism in bacteria, its role in this compound resistance in parasites like Leishmania appears less prominent based on current research. parasite-journal.org

Changes in Cellular Membrane Fluidity and Permeability Affecting Drug Uptake

Alterations in the composition and properties of the cell membrane can impact the uptake and accumulation of this compound. Decreased drug uptake due to altered membrane composition or increased membrane fluidity has been identified as a mechanism of resistance in Leishmania donovani. nih.govnih.govasm.orgparasite-journal.org Studies have shown that this compound-resistant L. donovani exhibit increased membrane fluidity, which is associated with decreased intracellular drug accumulation. nih.govnih.gov This suggests that changes in membrane properties can impair drug penetration into the parasite. frontiersin.orgnih.govasm.orgparasite-journal.org

Adaptive Responses and Increased Tolerance to Cellular Stress (e.g., Nitrosative Stress)

Parasites can develop adaptive responses to withstand the cellular stress induced by this compound. One such adaptation observed in this compound-resistant Leishmania is increased tolerance to nitrosative stress. frontiersin.orgnih.govnih.govasm.orgoup.comasm.org Macrophages, as part of the host immune response, produce reactive nitrogen intermediates (RNI), including nitric oxide (NO), which can be toxic to intracellular parasites. frontiersin.orgnih.gov this compound-resistant Leishmania strains have demonstrated enhanced survival in the presence of NO donors, indicating an improved ability to counteract nitrosative stress. nih.govoup.comasm.org This increased tolerance to host defense mechanisms contributes to the parasite's survival under drug pressure. frontiersin.orgnih.govnih.gov

Identification of Single Nucleotide Variations (SNPs) and Insertion/Deletion (Indel) Polymorphisms

Genomic analysis of this compound-resistant Leishmania strains has revealed the presence of single nucleotide variations (SNPs) and insertion/deletion (Indel) polymorphisms that may be associated with reduced susceptibility. Whole-genome sequencing studies comparing resistant strains to wild-type sensitive strains have identified numerous genomic variants. frontiersin.orgnih.gov For instance, one study identified 11 short nucleotide variations correlated with this compound resistance in Leishmania donovani. nih.govmdpi.com While many identified SNPs and Indels are located in intergenic regions or result in synonymous mutations, some are found within genes involved in various cellular processes. nih.govresearchgate.net Genes potentially associated with this compound resistance through SNVs include those involved in transcription, translation, protein turnover, virulence, mitochondrial function, signaling, and vesicular trafficking. nih.govmdpi.com Intergenic SNPs on chromosomes 18 and 35 have shown strong correlations with resistance, located upstream of genes like the chaperone DnaJ protein and aspartate aminotransferase. researchgate.net

Analysis of Gene Copy Number Variations and Chromosomal Somy Related to Resistance

Changes in gene copy number variations (CNVs) and chromosomal somy (aneuploidy) have also been linked to this compound resistance in Leishmania. nih.govresearchgate.netmdpi.com Studies have compared gene copy numbers and chromosome somies between this compound-resistant and sensitive Leishmania lines. nih.gov A total of 39 genes with copy number alterations were found to be correlated with this compound resistance in one study. nih.govmdpi.com These genes are implicated in diverse cellular functions, including transcription, translation, protein turnover, mitochondrial function, and vesicular trafficking. nih.govmdpi.com A significant increase in aneuploidy has been observed during the selection of this compound resistance in Leishmania donovani strains, which could facilitate the rapid selection of genetic changes conferring a survival advantage. nih.gov

Methodologies for Experimental Selection of Resistant Strains and Subsequent Genomic Characterization

Experimental selection is a key methodology for generating this compound-resistant strains in a controlled laboratory setting to study resistance mechanisms. This typically involves exposing parasites to increasing concentrations of the drug over time. nih.govparasite-journal.org For example, Leishmania donovani promastigotes resistant to high concentrations of this compound have been obtained through stepwise increases in drug pressure and cloning. parasite-journal.org Resistance can be selected in both promastigote and amastigote stages of the parasite. asm.org Following selection, genomic characterization, often through whole-genome sequencing (WGS), is performed to identify the genetic alterations associated with the acquired resistance. frontiersin.orgnih.govmdpi.com This comparative genomic analysis allows for the identification of SNPs, Indels, CNVs, and changes in chromosomal somy by comparing the genomes of resistant strains to their sensitive parental lines. nih.govresearchgate.netdntb.gov.ua

Investigation of Combination Therapy Regimens for Mitigating Resistance Emergence

Combination therapy involves using this compound alongside other drugs to enhance efficacy and potentially mitigate the emergence of resistance. frontiersin.orgpatsnap.com The rationale is that using multiple drugs with different mechanisms of action makes it more difficult for parasites to develop resistance simultaneously. plos.org Studies are investigating combination therapies including this compound with drugs like miltefosine or liposomal amphotericin B to improve effectiveness and reduce treatment duration. frontiersin.org For instance, research suggests that combining miltefosine and this compound may delay the onset of experimental drug resistance in Leishmania infantum. plos.orgmdpi.com This approach is being explored as a potential first-line option, particularly in regions where antimony resistance is prevalent. oup.com

Development of Novel Analogs Exhibiting Activity Against Resistant Phenotypes

Another strategy to combat this compound resistance is the development of novel this compound analogs. These modified compounds aim to retain or improve activity against resistant strains, potentially by evading existing resistance mechanisms. acs.orgmdpi.comnih.gov Research involves the chemical synthesis of this compound derivatives with targeted modifications. nih.gov For example, studies have explored apramycin-paromomycin analogues where structural modifications are made to the ring system involved in ribosomal binding. acs.orgnih.gov Some of these novel analogs have shown promising activity against bacterial strains resistant to parent compounds, suggesting their potential against resistant parasitic strains as well. acs.orgnih.gov The design of these analogs often focuses on overcoming enzymatic resistance or improving binding to the ribosomal target. mdpi.com