IU Indianapolis ScholarWorks :: Browsing by Author "Sun, Longhua"

Browsing by Author "Sun, Longhua"

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A Conserved Female-Specific Requirement for the GGT Gene in Mosquito Larvae Facilitates RNAi-Mediated Sex Separation in Multiple Species of Disease Vector Mosquitoes
(MDPI, 2022-01-27) Mysore, Keshava; Sun, Longhua; Li, Ping; Roethele, Joseph B.; Misenti, Joi K.; Kosmach, John; Igiede, Jessica; Duman-Scheel, Molly; Medical and Molecular Genetics, School of Medicine
Although several emerging mosquito control technologies are dependent on mass releases of adult males, methods of sex-sorting that can be implemented globally have not yet been established. RNAi screens led to the discovery of siRNA, which targets gamma-glutamyl transpeptidase (GGT), a gene which is well conserved in multiple species of mosquitoes and located at the sex-determining M locus region in Aedes aegypti. Silencing the A. aegypti, Aedes albopictus, Anopheles gambiae, Culex pipiens, and Culex quinquefasciatus GGT genes resulted in female larval death, with no significant impact on male survival. Generation of yeast strains that permitted affordable expression and oral delivery of shRNA corresponding to mosquito GGT genes facilitated larval target gene silencing and generated significantly increased 5 males:1 female adult ratios in each species. Yeast targeting a conserved sequence in Culex GGT genes was incorporated into a larval mass-rearing diet, permitting the generation of fit adult male C. pipiens and C. quinquefasciatus, two species for which labor-intensive manual sex separation had previously been utilized. The results of this study indicate that female-specific yeast-based RNAi larvicides may facilitate global implementation of population-based control strategies that require releases of sterile or genetically modified adult males, and that yeast RNAi strategies can be utilized in various species of mosquitoes that have progressed to different stages of sex chromosome evolution.
A Broad-Based Mosquito Yeast Interfering RNA Pesticide Targeting Rbfox1 Represses Notch Signaling and Kills Both Larvae and Adult Mosquitoes
(MDPI, 2021-09-28) Mysore, Keshava; Sun, Longhua; Hapairai, Limb K.; Wang, Chien-Wei; Roethele, Joseph B.; Igiede, Jessica; Scheel, Max P.; Scheel, Nicholas D.; Li, Ping; Wei, Na; Severson, David W.; Duman-Scheel, Molly; Medical and Molecular Genetics, School of Medicine
Prevention of mosquito-borne infectious diseases will require new classes of environmentally safe insecticides and novel mosquito control technologies. Saccharomyces cerevisiae was engineered to express short hairpin RNA (shRNA) corresponding to mosquito Rbfox1 genes. The yeast induced target gene silencing, resulting in larval death that was observed in both laboratory and outdoor semi-field trials conducted on Aedes aegypti. High levels of mortality were also observed during simulated field trials in which adult females consumed yeast delivered through a sugar bait. Mortality correlated with defects in the mosquito brain, in which a role for Rbfox1 as a positive regulator of Notch signaling was identified. The larvicidal and adulticidal activities of the yeast were subsequently confirmed in trials conducted on Aedes albopictus, Anopheles gambiae, and Culex quinquefasciatus, yet the yeast had no impact on survival of select non-target arthropods. These studies indicate that yeast RNAi pesticides targeting Rbfox1 could be further developed as broad-based mosquito larvicides and adulticides for deployment in integrated biorational mosquito control programs. These findings also suggest that the species-specificity of attractive targeted sugar baits, a new paradigm for vector control, could potentially be enhanced through RNAi technology, and specifically through the use of yeast-based interfering RNA pesticides.
Characterization of a broad-based mosquito yeast interfering RNA larvicide with a conserved target site in mosquito semaphorin-1a genes
(Springer Nature, 2019-05-22) Mysore, Keshava; Li, Ping; Wang, Chien-Wei; Hapairai, Limb K.; Scheel, Nicholas D.; Realey, Jacob S.; Sun, Longhua; Severson, David W.; Wei, Na; Duman-Scheel, Molly; Medical and Molecular Genetics, School of Medicine
BACKGROUND: RNA interference (RNAi), which has facilitated functional characterization of mosquito neural development genes such as the axon guidance regulator semaphorin-1a (sema1a), could one day be applied as a new means of vector control. Saccharomyces cerevisiae (baker's yeast) may represent an effective interfering RNA expression system that could be used directly for delivery of RNA pesticides to mosquito larvae. Here we describe characterization of a yeast larvicide developed through bioengineering of S. cerevisiae to express a short hairpin RNA (shRNA) targeting a conserved site in mosquito sema1a genes. RESULTS: Experiments conducted on Aedes aegypti larvae demonstrated that the yeast larvicide effectively silences sema1a expression, generates severe neural defects, and induces high levels of larval mortality in laboratory, simulated-field, and semi-field experiments. The larvicide was also found to induce high levels of Aedes albopictus, Anopheles gambiae and Culex quinquefasciatus mortality. CONCLUSIONS: The results of these studies indicate that use of yeast interfering RNA larvicides targeting mosquito sema1a genes may represent a new biorational tool for mosquito control.
Characterization of a novel RNAi yeast insecticide that silences mosquito 5-HT1 receptor genes
(Springer Nature, 2023-12-15) Mysore, Keshava; Njoroge, Teresia M.; Stewart, Akilah T. M.; Winter, Nikhella; Hamid‑Adiamoh, Majidah; Sun, Longhua; Shui Feng, Rachel; James, Lester D.; Mohammed, Azad; Severson, David W.; Duman‑Scheel, Molly; Medical and Molecular Genetics, School of Medicine
G protein-coupled receptors (GPCRs), which regulate numerous intracellular signaling cascades that mediate many essential physiological processes, are attractive yet underexploited insecticide targets. RNA interference (RNAi) technology could facilitate the custom design of environmentally safe pesticides that target GPCRs in select target pests yet are not toxic to non-target species. This study investigates the hypothesis that an RNAi yeast insecticide designed to silence mosquito serotonin receptor 1 (5-HTR1) genes can kill mosquitoes without harming non-target arthropods. 5-HTR.426, a Saccharomyces cerevisiae strain that expresses an shRNA targeting a site specifically conserved in mosquito 5-HTR1 genes, was generated. The yeast can be heat-inactivated and delivered to mosquito larvae as ready-to-use tablets or to adult mosquitoes using attractive targeted sugar baits (ATSBs). The results of laboratory and outdoor semi-field trials demonstrated that consumption of 5-HTR.426 yeast results in highly significant mortality rates in Aedes, Anopheles, and Culex mosquito larvae and adults. Yeast consumption resulted in significant 5-HTR1 silencing and severe neural defects in the mosquito brain but was not found to be toxic to non-target arthropods. These results indicate that RNAi insecticide technology can facilitate selective targeting of GPCRs in intended pests without impacting GPCR activity in non-targeted organisms. In future studies, scaled production of yeast expressing the 5-HTR.426 RNAi insecticide could facilitate field trials to further evaluate this promising new mosquito control intervention.
Characterization of an adulticidal and larvicidal interfering RNA pesticide that targets a conserved sequence in mosquito G protein-coupled dopamine 1 receptor genes
(Elsevier, 2020) Hapairai, Limb K.; Mysore, Keshava; Sun, Longhua; Li, Ping; Wang, Chien-Wei; Scheel, Nicholas D.; Lesnik, Alexandra; Scheel, Max P.; Igiede, Jessica; Wei, Na; Severson, David W.; Duman-Scheel, Molly; Medical and Molecular Genetics, School of Medicine
G protein-coupled receptors (GPCRs), key regulators of a variety of critical biological processes, are attractive targets for insecticide development. Given the importance of these receptors in many organisms, including humans, it is critical that novel pesticides directed against GPCRs are designed to be species-specific. Here, we present characterization of an interfering RNA pesticide (IRP) targeting the mosquito GPCR-encoding dopamine 1 receptor (dop1) genes. A small interfering RNA corresponding to dop1 was identified in a screen for IRPs that kill Aedes aegypti during both the adult and larval stages. The 25 bp sequence targeted by this IRP is conserved in the dop1 genes of multiple mosquito species, but not in non-target organisms, indicating that it could function as a biorational mosquito insecticide. Aedes aegypti adults treated through microinjection or attractive toxic sugar bait delivery of small interfering RNA corresponding to the target site exhibited severe neural and behavioral defects and high levels of adult mortality. Likewise, A. aegypti larval consumption of dried inactivated yeast tablets prepared from a Saccharomyces cerevisiae strain engineered to express short hairpin RNA corresponding to the dop1 target site resulted in severe neural defects and larval mortality. Aedes albopictus and Anopheles gambiae adult and larval mortality was also observed following treatment with dop1 IRPs, which were not toxic to non-target arthropods. The results of this investigation indicate that dop1 IRPs can be used for species-specific targeting of dop1 GPCRs and may represent a new biorational strategy for control of both adult and larval mosquitoes.
A conserved female-specific larval requirement for MtnB function facilitates sex separation in multiple species of disease vector mosquitoes
(BMC, 2021-06-26) Mysore, Keshava; Sun, Longhua; Roethele, Joseph B.; Li, Ping; Igiede, Jessica; Misenti, Joi K.; Duman‑Scheel, Molly; Medical and Molecular Genetics, School of Medicine
Background: Clusters of sex-specific loci are predicted to shape the boundaries of the M/m sex-determination locus of the dengue vector mosquito Aedes aegypti, but the identities of these genes are not known. Identification and characterization of these loci could promote a better understanding of mosquito sex chromosome evolution and lead to the elucidation of new strategies for male mosquito sex separation, a requirement for several emerging mosquito population control strategies that are dependent on the mass rearing and release of male mosquitoes. This investigation revealed that the methylthioribulose-1-phosphate dehydratase (MtnB) gene, which resides adjacent to the M/m locus and encodes an evolutionarily conserved component of the methionine salvage pathway, is required for survival of female larvae. Results: Larval consumption of Saccharomyces cerevisiae (yeast) strains engineered to express interfering RNA corresponding to MtnB resulted in target gene silencing and significant female death, yet had no impact on A. aegypti male survival or fitness. Integration of the yeast larvicides into mass culturing protocols permitted scaled production of fit adult male mosquitoes. Moreover, silencing MtnB orthologs in Aedes albopictus, Anopheles gambiae, and Culex quinquefasciatus revealed a conserved female-specific larval requirement for MtnB among different species of mosquitoes. Conclusions: The results of this investigation, which may have important implications for the study of mosquito sex chromosome evolution, indicate that silencing MtnB can facilitate sex separation in multiple species of disease vector insects.
Correction: Mysore et al. A Broad-Based Mosquito Yeast Interfering RNA Pesticide Targeting Rbfox1 Represses Notch Signaling and Kills Both Larvae and Adult Mosquitoes. Pathogens 2021, 10, 1251
(MDPI, 2022-08-23) Mysore, Keshava; Sun, Longhua; Hapairai, Limb K.; Wang, Chien-Wei; Roethele, Joseph B.; Igiede, Jessica; Scheel, Max P.; Scheel, Nicholas D.; Li, Ping; Wei, Na; Severson, David W.; Duman-Scheel, Molly; Medical and Molecular Genetics, School of Medicine
In the original publication [1], there was a mistake in Figure 1 as published. The wrong graph was inadvertently included in panel 1f (dose–response curve). Additionally, the original image for the gel shown in panel 1a is now included in the Supplementary Materials.
Death effector domain-containing protein induces vulnerability to cell cycle inhibition in triple-negative breast cancer
(Springer Nature, 2019-06-28) Ni, Yingjia; Schmidt, Keon R.; Werner, Barnes A.; Koenig, Jenna K.; Guldner, Ian H.; Schnepp, Patricia M.; Tan, Xuejuan; Jiang, Lan; Host, Misha; Sun, Longhua; Howe, Erin N.; Wu, Junmin; Littlepage, Laurie E.; Nakshatri, Harikrishna; Zhang, Siyuan; Surgery, IU School of Medicine
Lacking targetable molecular drivers, triple-negative breast cancer (TNBC) is the most clinically challenging subtype of breast cancer. In this study, we reveal that Death Effector Domain-containing DNA-binding protein (DEDD), which is overexpressed in > 60% of TNBCs, drives a mitogen-independent G1/S cell cycle transition through cytoplasm localization. The gain of cytosolic DEDD enhances cyclin D1 expression by interacting with heat shock 71 kDa protein 8 (HSC70). Concurrently, DEDD interacts with Rb family proteins and promotes their proteasome-mediated degradation. DEDD overexpression renders TNBCs vulnerable to cell cycle inhibition. Patients with TNBC have been excluded from CDK 4/6 inhibitor clinical trials due to the perceived high frequency of Rb-loss in TNBCs. Interestingly, our study demonstrated that, irrespective of Rb status, TNBCs with DEDD overexpression exhibit a DEDD-dependent vulnerability to combinatorial treatment with CDK4/6 inhibitor and EGFR inhibitor in vitro and in vivo. Thus, our study provided a rationale for the clinical application of CDK4/6 inhibitor combinatorial regimens for patients with TNBC.
Demonstration of RNAi Yeast Insecticide Activity in Semi-Field Larvicide and Attractive Targeted Sugar Bait Trials Conducted on Aedes and Culex Mosquitoes
(MDPI, 2023-12-15) Stewart, Akilah T. M.; Mysore, Keshava; Njoroge, Teresia M.; Winter, Nikhella; Shui Feng, Rachel; Singh, Satish; James, Lester D.; Singkhaimuk, Preeraya; Sun, Longhua; Mohammed, Azad; Oxley, James D.; Duckham, Craig; Ponlawat, Alongkot; Severson, David W.; Duman-Scheel, Molly; Medical and Molecular Genetics, School of Medicine
Eco-friendly new mosquito control innovations are critical for the ongoing success of global mosquito control programs. In this study, Sh.463_56.10R, a robust RNA interference (RNAi) yeast insecticide strain that is suitable for scaled fermentation, was evaluated under semi-field conditions. Inactivated and dried Sh.463_56.10R yeast induced significant mortality of field strain Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus larvae in semi-field larvicide trials conducted outdoors in St. Augustine, Trinidad, where 100% of the larvae were dead within 24 h. The yeast was also stably suspended in commercial bait and deployed as an active ingredient in miniature attractive targeted sugar bait (ATSB) station sachets. The yeast ATSB induced high levels of Aedes and Culex mosquito morbidity in semi-field trials conducted in Trinidad, West Indies, as well as in Bangkok, Thailand, in which the consumption of the yeast resulted in adult female mosquito death within 48 h, faster than what was observed in laboratory trials. These findings support the pursuit of large-scale field trials to further evaluate the Sh.463_56.10R insecticide, a member of a promising new class of species-specific RNAi insecticides that could help combat insecticide resistance and support effective mosquito control programs worldwide.
Evaluation of large volume yeast interfering RNA lure-and-kill ovitraps for attraction and control of Aedes mosquitoes
(Wiley, 2021-09) Hapairai, Limb K.; Mysore, Keshava; James, Lester D.; Scheel, Nicholas D.; Realey, Jacob S.; Sun, Longhua; Gerber, Laura E.; Feng, Rachel Shui; Romero-Severson, Ethan; Mohammed, Azad; Duman-Scheel, Molly; Severson, David W.; Medical and Molecular Genetics, School of Medicine
Aedes mosquitoes (Diptera: Culicidae), principle vectors of several arboviruses, typically lay eggs in man-made water-filled containers located near human dwellings. Given the widespread emergence of insecticide resistance, stable and biofriendly alternatives for mosquito larviciding are needed. Laboratory studies have demonstrated that inactivated yeast interfering RNA tablets targeting key larval developmental genes can be used to facilitate effective larvicidal activity while also promoting selective gravid female oviposition behaviour. Here we examined the efficacy of transferring this technology toward development of lure-and-kill ovitraps targeting Aedes aegypti (L.) and Aedes albopictus (Skuse) female mosquitoes. Insectary, simulated field and semi-field experiments demonstrated that two mosquito-specific yeast interfering RNA pesticides induce high levels of mortality among larvae of both species in treated large volume containers. Small-scale field trials conducted in Trinidad, West Indies demonstrated that large volume ovitrap containers baited with inactivated yeast tablets lure significantly more gravid females than traps containing only water and were highly attractive to both A. aegypti and A. albopictus females. These studies indicate that development of biorational yeast interfering RNA-baited ovitraps may represent a new tool for control of Aedes mosquitoes, including deployment in existing lure-and-kill ovitrap technologies or traditional container larviciding programs.

Browsing by Author "Sun, Longhua"

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