drug resistance mutations
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2021 ◽  
Author(s):  
Pallavi M Gosavi ◽  
Kevin C Ngan ◽  
Megan Yeo ◽  
Cindy Su ◽  
Jiaming Li ◽  
...  

Targeted protein degradation (TPD) holds immense promise for drug discovery but mechanisms of acquired resistance to degraders remain to be fully identified. Here we used CRISPR-suppressor scanning to identify mechanistic classes of drug resistance mutations to molecular glue degraders in GSPT1 and RBM39, neosubstrates targeted by E3 ligase substrate receptors cereblon and DCAF15, respectively. While many mutations directly alter the ternary complex heterodimerization surface, distal resistance sites were also identified. Several distal mutations in RBM39 led to modest decreases in degradation yet can enable cell survival, underscoring how small differences in degradation can lead to resistance. Integrative analysis of resistance sites across GSPT1 and RBM39 revealed varying levels of sequence conservation and mutational constraint that control the emergence of different resistance mechanisms, highlighting that many regions co-opted by TPD are inessential. Altogether, our study identifies common resistance mechanisms for molecular glue degraders and outlines a general approach to survey neosubstrate requirements necessary for effective degradation.


Author(s):  
Saba Garshasbi ◽  
Arezoo Marjani ◽  
Ali Alipour ◽  
Khadijeh Khanaliha ◽  
Maryam Esghaei ◽  
...  

Background and Objectives: Human immunodeficiency virus (HIV) has various transmission routes. Instant antiretroviral therapy (ART) is the recommended treatment for HIV infection. Highly active antiretroviral therapy (HAART) significantly decreases the acquired immunodeficiency syndrome (AIDS) and AIDS-related co-morbidities. Notwithstanding the suit- ability of HAART, the antiretrovirals (ARVs) have adverse effects and antiretroviral drug resistance mutations are reported among those who receive ARVs. In this survey, the abundance of HIV-1 infection in Iranians with high-risk behaviors, and detection of the surveillance drug-resistant mutations (SDRMs) were evaluated. Materials and Methods: This cross-sectional study was conducted on 250 individuals with high-risk behaviors from Sep- tember 2014 to February 2020. HIV-1 Ag/Ab in plasma samples was detected using enzyme immunoassay (EIA) kits. The conserved region of HIV-1 was detected in the plasma samples by real-time polymerase chain reaction (PCR) assay. Further- more, in individuals with positive HIV-1 RNA, HIV-1 viral load testing was performed. After amplification and sequencing of the HIV-1 protease, reverse transcriptase, and integrase genes, surveillance drug resistance mutation (SDRM) and phylo- genetic analysis were determined. Results: Out of the 250 participants with high-risk behaviors, six (2.4%) were infected with HIV-1. According to the phy- logenetic analysis, the CRF35_AD (83.3% or 5/6) was the dominant subtype, followed by CRF01_AE (16.7% or 1/6). In this research, in none of the HIV-1 infected patients, SDRM for protease inhibitors (PIs), nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), and integrase inhibitors (INs) were observed. Nevertheless, in one of the patients, V179L mutation was detected which is a rare non-polymorphic mutation and is listed as a rilpivirine (RPV) -associated resistance mutation. Conclusion: The results of the current survey revealed that 2.4% of people with high-risk behaviors are infected with HIV and the level of drug resistance mutations (DRMs) in these people is very low.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Ying-An Chen ◽  
Tsen-Ju Shiu ◽  
Lien-Fen Tseng ◽  
Chien-Fu Cheng ◽  
Wei-Liang Shih ◽  
...  

Abstract Background With effective vector control and case management, substantial progress has been made towards eliminating malaria on the islands of São Tomé and Príncipe (STP). This study assessed the dynamic changes in the genetic diversity of Plasmodium falciparum, the anti-malarial drug resistance mutations, and malaria treatment outcomes between 2010 and 2016 to provide insights for the prevention of malaria rebounding. Methods Polymorphic regions of merozoite surface proteins 1 and 2 (msp1 and msp2) were sequenced in 118 dried blood spots (DBSs) collected from malaria patients who had visited the Central Hospital in 2010–2016. Mutations in the multi-drug resistance I (pfmdr1), chloroquine resistance transporter (pfcrt), and kelch 13 (pfk13) genes were analysed by polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP) and sequencing in 111 DBSs. A total of 7482 cases that completed a 28-day follow-up were evaluated for treatment outcomes based on the microscopic results. Regression models were used to characterize factors associated with levels of parasite density and treatment failures. Results Parasite strains in STP showed significant changes during and after the peak incidence in 2012. The prevalent allelic type in msp1 changed from K1 to MAD20, and that in msp2 changed from 3D7/IC to FC27. The dominant alleles of drug-resistance markers were pfmdr1 86Y, 184F, D1246, and pfcrt 76 T (Y-F-D-T, 51.4%). The average parasite density in malaria cases declined threefold from low-transmission (2010–2013) to pre-elimination period (2014–2016). Logistic regression models showed that patients with younger age (OR for age = 0.97–0.98, p < 0.001), higher initial parasite density (log10-transformed, OR = 1.44, p < 0.001), and receiving quinine treatment (compared to artemisinin-based combination therapy, OR = 1.91–1.96, p < 0.001) were more likely to experience treatment failures during follow-up. Conclusions Plasmodium falciparum in STP had experienced changes in prevalent strains, and increased mutation frequencies in drug-resistance genes from the low-transmission to the pre-elimination settings. Notably, patients with younger age and receiving quinine treatment were more likely to show parasitological treatment failure during follow-up. Therapeutic efficacy should be carefully monitored to inform future treatment policy in STP.


2021 ◽  
Vol 51 ◽  
pp. 56-64
Author(s):  
Luc Blassel ◽  
Anna Zhukova ◽  
Christian J Villabona-Arenas ◽  
Katherine E Atkins ◽  
Stéphane Hué ◽  
...  

2021 ◽  
Vol 19 ◽  
Author(s):  
Rabia Can Sarinoglu ◽  
Uluhan Sili ◽  
Ufuk Hasdemir ◽  
Burak Aksu ◽  
Guner Soyletir ◽  
...  

Background: The World Health Organization (WHO) recommends the surveillance of transmitted drug resistance mutations (TDRMs) to ensure the effectiveness and sustainability of HIV treatment programs. Objective: Our aim was to determine the TDRMs and evaluate the distribution of HIV-1 subtypes using and compared next-generation sequencing (NGS) and Sanger-based sequencing (SBS) in a cohort of 44 antiretroviral treatment-naïve patients. Methods: All samples that were referred to the microbiology laboratory for HIV drug resistance analysis between December 2016 and February 2018 were included in the study. After exclusions, 44 treatment-naive adult patients with a viral load of >1000 copies/mL were analyzed. DNA sequencing for reverse transcriptase and protease regions was performed using both DeepChek ABL single round kit and Sanger-based ViroSeq HIV-1 Genotyping System. The mutations and HIV-1 subtypes were analyzed using the Stanford HIVdb version 8.6.1 Genotypic Resistance software, and TDRMs were assessed using the WHO surveillance drug-resistance mutation database. HIV-1 subtypes were confirmed by constructing a maximum-likelihood phylogenetic tree using Los Alamos IQ-Tree software. Results: NGS identified nucleos(t)ide reverse transcriptase inhibitor (NRTI)-TDRMs in 9.1% of the patients, non-nucleos(t)ide reverse transcriptase inhibitor (NNRTI)-TDRMs in 6.8% of the patients, and protease inhibitor (PI)-TDRMs in 18.2% of the patients at a detection threshold of ≥1%. Using SBS, 2.3% and 6.8% of the patients were found to have NRTI- and NNRTI-TDRMs, respectively, but no major PI mutations were detected. M41L, L74I, K65R, M184V, and M184I related to NRTI, K103N to NNRTI, and N83D, M46I, I84V, V82A, L24I, L90M, I54V to the PI sites were identified using NGS. Most mutations were found in low-abundance (frequency range: 1.0% - 4.7%) HIV-1 variants, except M41L and K103N. The subtypes of the isolates were found as follows; 61.4% subtype B, 18.2% subtype B/CRF02_AG recombinant, 13.6% subtype A, 4.5% CRF43_02G, and 2.3% CRF02_AG. All TDRMs, except K65R, were detected in HIV-1 subtype B isolates.. Conclusion: The high diversity of protease site TDRMs in the minority HIV-1 variants and prevalence of CRFs were remarkable in this study. All minority HIV-1 variants were missed by conventional sequencing. TDRM prevalence among minority variants appears to be decreasing over time at our center.


2021 ◽  
Vol 9 (11) ◽  
pp. 2355
Author(s):  
Ferdinand Emaniel Brel Got ◽  
Patricia Recordon-Pinson ◽  
Ghislain Loubano-Voumbi ◽  
Dagene Ebourombi ◽  
Marie-Lise Blondot ◽  
...  

Background: HIV infects around one hundred thousand patients in the Republic of the Congo. Approximately 25% of them receive an antiretroviral treatment; current first-line regimens include two NRTIs and one NNRTI, reverse transcriptase inhibitors. Recently, protease inhibitors (PIs) were also introduced as second-line therapy upon clinical signs of treatment failure. Due to the limited number of molecular characterizations and amount of drug resistance data available in the Republic of the Congo, this study aims to evaluate the prevalence of circulating resistance mutations within the pol region. Methods: HIV-positive, ART-experienced patients have been enrolled in four semi-urban localities in the Republic of the Congo. Plasma samples were collected, and viral RNA was extracted. The viral load for each patient was evaluated by RT-qPCR, following the general diagnostic procedures of the University Hospital of Bordeaux. Finally, drug resistance genotyping and phylogenetic analysis were conducted following Sanger sequencing of the pol region. Results: A high diversity of HIV-1 strains was observed with many recombinant forms. Drug resistance mutations in RT and PR genes were determined and correlated to HAART. Because integrase inhibitors are rarely included in treatments in the Republic of the Congo, the prevalence of integrase drug resistance mutations before treatment was also determined. Interestingly, very few mutations were observed. Conclusions: We confirmed a high diversity of HIV-1 in the Republic of the Congo. Most patients presented an accumulation of mutations conferring resistance against NRTIs, NNRTIs and PIs. Nonetheless, the absence of integrase mutations associated with drug resistance suggests that the introduction of integrase inhibitors into therapy will be highly beneficial to patients in the Republic of the Congo.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11794
Author(s):  
Ozkan Aydemir ◽  
Benedicta Mensah ◽  
Patrick W. Marsh ◽  
Benjamin Abuaku ◽  
James Leslie Myers-Hansen ◽  
...  

Antimalarial resistance surveillance in sub-Saharan Africa is often constrained by logistical and financial challenges limiting its breadth and frequency. At two sites in Ghana, we have piloted a streamlined sample pooling process created immediately by sequential addition of positive malaria cases at the time of diagnostic testing. This streamlined process involving a single tube minimized clinical and laboratory work and provided accurate frequencies of all known drug resistance mutations after high-throughput targeted sequencing using molecular inversion probes. Our study validates this method as a cost-efficient, accurate and highly-scalable approach for drug resistance mutation monitoring that can potentially be applied to other infectious diseases such as tuberculosis.


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