scholarly journals ACaulobacter crescentusMicrobicide Protects from Vaginal Infection with HIV-1JR-CSFin Humanized Bone Marrow-Liver-Thymus Mice

2019 ◽  
Vol 93 (18) ◽  
Author(s):  
Christina Farr Zuend ◽  
John F. Nomellini ◽  
John Smit ◽  
Marc S. Horwitz
Keyword(s):  
Bone Marrow ◽  
Mouse Model ◽  
Caulobacter Crescentus ◽  
Sub Saharan Africa ◽  
Significant Protection ◽  
Vaginal Infection ◽  
Content Type ◽  
Vaginal Tract ◽  
Prevention Option ◽  
Hiv 1

ABSTRACTOver 2 million people are infected with HIV-1 annually. Approximately half of these new infections occur in women residing in low-income countries, where their access to and control over HIV-1 preventative measures are often limited, indicating that female-controlled prevention options for HIV-1 are urgently needed. Microbicides that can be topically applied to the vaginal tract in advance of sexual activity represent a promising female-controlled prevention option for HIV-1. We have previously described the development of an HIV-1-specific microbicide using the surface or S-layer recombinant protein display capabilities of the nonpathogenic, freshwater bacteriumCaulobacter crescentus. RecombinantC. crescentusbacteria were created that displayed proteins that interfere with the HIV-1 attachment and entry process and that were able to provide significant protection of TZM-bl cells from infection with HIV-1 pseudovirus. These studies have been expanded to investigate if these recombinantC. crescentusbacteria are able to maintain efficacy with replication-competent HIV-1 and both TZM-bl cells and human peripheral blood mononuclear cells (PBMCs). In addition, we utilized the humanized bone marrow-liver-thymus (BLT) mouse model to determine if vaginal application of recombinantC. crescentusat the time of HIV-1JR-CSFinfection could provide protection from HIV-1 infection. RecombinantC. crescentusbacteria expressing Griffithsin, GB virus C E2 protein, elafin, α-1-antitrypsin, indolicidin, and the fusion inhibitor T-1249 were able to protect 40 to 75% of the BLT mice from vaginal infection with HIV-1JR-CSF, withC. crescentusbacteria expressing Griffithsin being the most effective. Taken together, these data suggest that aC. crescentus-based microbicide could be a safe and effective method for HIV-1 prevention.IMPORTANCEHuman immunodeficiency virus (HIV) disproportionally infects young women in sub-Saharan Africa. Current HIV-1 prevention options have had limited success among women, suggesting that alternative, female-controlled prevention options need to be developed. Microbicides that can be applied to the vaginal tract are a promising prevention option. In this study, we describe the testing of 15 potential candidates for inhibition of HIV-1 infection in a humanized mouse model of HIV-1 infection. Four of these candidates were able to provide significant protection from vaginal infection with HIV-1, with the most successful candidate protecting 75% of the mice from infection. This study describes the preclinical testing of a new strategy that could be a safe and effective option for HIV-1 prevention in women.

scholarly journals Enhanced Neutralization of HIV by Antibodies Displayed on the S-Layer of Caulobacter crescentus

2011 ◽  
Vol 55 (12) ◽  
pp. 5547-5552 ◽  
Author(s):  
Mark Duval ◽  
Christopher J. Lewis ◽  
John F. Nomellini ◽  
Marc S. Horwitz ◽  
John Smit ◽  
...  
Keyword(s):  
Nonhuman Primates ◽  
Caulobacter Crescentus ◽  
Low Cost ◽  
Content Type ◽  
Innovative Methods ◽  
Hiv Antibodies ◽  
The Cost ◽  
Anti Hiv Agents ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACTInnovative methods of prevention are needed to stop the more than two million new HIV-1 infections annually, particularly in women. Local application of anti-HIV antibodies has been shown to be effective at preventing infection in nonhuman primates; however, the concentrations needed are cost prohibitive. Display of antibodies on a particulate platform will likely prolong effectiveness of these anti-HIV agents and lower the cost of goods. Here, we demonstrate that the bacteriumCaulobacter crescentusand its highly expressed surface-layer (S-layer) protein can provide this antibody display platform. Caulobacters displaying protein G, alone or with CD4 codisplay, successfully captured HIV-1-specific antibodies and demonstrated functional neutralization. Compared to soluble antibodies, a neutralizing anti-HIV antibody displayed onCaulobacterwas as effective or more effective at neutralizing diverse HIV-1 isolates. Moreover, when an antibody reactive with an epitope induced by CD4 binding (CD4i) was codisplayed with CD4, there was significant enhancement in HIV-1 neutralization. These results suggest that caulobacters displaying anti-HIV antibodies offer a distinct improvement in the use of antibodies as microbicides. Furthermore, these reagents can specifically evaluate anti-HIV antibodies in concert with other HIV-1 blocking agents to assess the most suitable tools for conversion to scFvs, allowing for direct display within the S-layer protein and further reducing cost of goods. In summary,C. crescentus, which can be easily produced and chemically stabilized at low cost, is well suited for engineering as an effective platform, offering an inexpensive way to produce and deliver HIV-1-specific microbicides.

scholarly journals Identification of Key Determinants of Staphylococcus aureus Vaginal Colonization

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Liwen Deng ◽  
Katrin Schilcher ◽  
Lindsey R. Burcham ◽  
Jakub M. Kwiecinski ◽  
Paige M. Johnson ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Mouse Model ◽  
Female Reproductive Tract ◽  
Transport Systems ◽  
Postpartum Women ◽  
Content Type ◽  
Vaginal Colonization ◽  
Fibrinogen Binding ◽  
Vaginal Tract

ABSTRACT Staphylococcus aureus is an important pathogen responsible for nosocomial and community-acquired infections in humans, and methicillin-resistant S. aureus (MRSA) infections have continued to increase despite widespread preventative measures. S. aureus can colonize the female vaginal tract, and reports have suggested an increase in MRSA infections in pregnant and postpartum women as well as outbreaks in newborn nurseries. Currently, little is known about specific factors that promote MRSA vaginal colonization and subsequent infection. To study S. aureus colonization of the female reproductive tract in a mammalian system, we developed a mouse model of S. aureus vaginal carriage and demonstrated that both hospital-associated and community-associated MRSA isolates can colonize the murine vaginal tract. Immunohistochemical analysis revealed an increase in neutrophils in the vaginal lumen during MRSA colonization. Additionally, we observed that a mutant lacking fibrinogen binding adhesins exhibited decreased persistence within the mouse vagina. To further identify novel factors that promote vaginal colonization, we performed RNA sequencing to determine the transcriptome of MRSA growing in vivo during vaginal carriage at 5 h, 1 day, and 3 days postinoculation. Over 25% of the bacterial genes were differentially regulated at all time points during colonization compared to laboratory cultures. The most highly induced genes were those involved in iron acquisition, including the Isd system and siderophore transport systems. Mutants deficient in these pathways did not persist as well during in vivo colonization. These results reveal that fibrinogen binding and the capacity to overcome host nutritional limitation are important determinants of MRSA vaginal colonization. IMPORTANCE Staphylococcus aureus is an opportunistic pathogen able to cause a wide variety of infections in humans. Recent reports have suggested an increasing prevalence of MRSA in pregnant and postpartum women, coinciding with the increased incidence of MRSA infections in neonatal intensive care units (NICUs) and newborn nurseries. Vertical transmission from mothers to infants at delivery is a likely route of MRSA acquisition by the newborn; however, essentially nothing is known about host and bacterial factors that influence MRSA carriage in the vagina. Here, we established a mouse model of vaginal colonization and observed that multiple MRSA strains can persist in the vaginal tract. Additionally, we determined that MRSA interactions with fibrinogen and iron uptake can promote vaginal persistence. This study is the first to identify molecular mechanisms which govern vaginal colonization by MRSA, the critical initial step preceding infection and neonatal transmission.

scholarly journals Pharmacokinetics and Preliminary Safety of Pod-Intravaginal Rings Delivering the Monoclonal Antibody VRC01-N for HIV Prophylaxis in a Macaque Model

2017 ◽  
Vol 61 (7) ◽  
Author(s):  
Chunxia Zhao ◽  
Manjula Gunawardana ◽  
Francois Villinger ◽  
Marc M. Baum ◽  
Mariana Remedios-Chan ◽  
...  
Keyword(s):  
Neutralizing Antibody ◽  
Sub Saharan Africa ◽  
Release Rates ◽  
Content Type ◽  
Macaque Model ◽  
Intravaginal Rings ◽  
Broadly Neutralizing Antibody ◽  
Sub Saharan ◽  
Hiv 1

ABSTRACT The broadly neutralizing antibody (bNAb) VRC01, capable of neutralizing 91% of known human immunodeficiency virus type 1 (HIV-1) isolates in vitro, is a promising candidate microbicide for preventing sexual HIV infection when administered topically to the vagina; however, accessibility to antibody-based prophylactic treatment by target populations in sub-Saharan Africa and other underdeveloped regions may be limited by the high cost of conventionally produced antibodies and the limited capacity to manufacture such antibodies. Intravaginal rings of the pod design (pod-IVRs) delivering Nicotiana-manufactured VRC01 (VRC01-N) over a range of release rates have been developed. The pharmacokinetics and preliminary safety of VRC01-N pod-IVRs were evaluated in a rhesus macaque model. The devices sustained VRC01-N release for up to 21 days at controlled rates, with mean steady-state VRC01-N levels in vaginal fluids in the range of 102 to 103 μg g−1 being correlated with in vitro release rates. No adverse safety indications were observed. These findings indicate that pod-IVRs are promising devices for the delivery of the candidate topical microbicide VRC01-N against HIV-1 infection and merit further preclinical evaluation.

scholarly journals Depot medroxyprogesterone acetate (DMPA) enhances susceptibility and increases the window of vulnerability to HIV-1 in humanized mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jocelyn M. Wessels ◽  
Philip V. Nguyen ◽  
Danielle Vitali ◽  
Kristen Mueller ◽  
Fatemeh Vahedi ◽  
...  
Keyword(s):  
T Cells ◽  
Medroxyprogesterone Acetate ◽  
Peripheral Blood ◽  
Sub Saharan Africa ◽  
Hormonal Contraceptives ◽  
Target Cells ◽  
Depot Medroxyprogesterone Acetate ◽  
Vaginal Tract ◽  
Window Of Vulnerability ◽  
Hiv 1

AbstractThe progestin-based hormonal contraceptive Depot Medroxyprogesterone Acetate (DMPA) is widely used in sub-Saharan Africa, where HIV-1 is endemic. Meta-analyses have shown that women using DMPA are 40% more likely than women not using hormonal contraceptives to acquire Human Immunodeficiency Virus (HIV-1). Therefore understanding how DMPA increases susceptibility to HIV-1 is an important public health issue. Using C57BL/6 mice and our previously optimized humanized mouse model (NOD-Rag1tm1Mom Il2rgtm1Wjl transplanted with hCD34-enriched hematopoietic stem cells; Hu-mice) where peripheral blood and tissues are reconstituted by human immune cells, we assessed how DMPA affected mucosal barrier function, HIV-1 susceptibility, viral titres, and target cells compared to mice in the diestrus phase of the estrous cycle, when endogenous progesterone is highest. We found that DMPA enhanced FITC-dextran dye leakage from the vaginal tract into the systemic circulation, enhanced target cells (hCD68+ macrophages, hCD4+ T cells) in the vaginal tract and peripheral blood (hCD45+hCD3+hCD4+hCCR5+ T cells), increased the rate of intravaginal HIV-1 infection, extended the window of vulnerability, and lowered vaginal viral titres following infection. These findings suggest DMPA may enhance susceptibility to HIV-1 in Hu-mice by impairing the vaginal epithelial barrier, increasing vaginal target cells (including macrophages), and extending the period of time during which Hu-mice are susceptible to infection; mechanisms that might also affect HIV-1 susceptibility in women.

scholarly journals The FLT3 Inhibitor Quizartinib Provides a Novel Strategy to Inhibit Chemotherapy-Induced Myelosuppression

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4041-4041
Author(s):  
Wallace Y Langdon ◽  
Samuel J Taylor ◽  
Johanna M Duyvestyn ◽  
Samantha A Dagger ◽  
George S. Vassiliou ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Single Dose ◽  
Mouse Model ◽  
Induction Therapy ◽  
Rapid Recovery ◽  
Significant Protection ◽  
Priming Dose ◽  
Hematopoietic Stem ◽  
Flt3 Inhibitor ◽  
Multiple Cycles

Abstract Introduction Chemotherapy-inducedmyelosuppressionis a major complication for cancer patients causing high rates of morbidity and mortality. Furthermore,myelosuppressionis frequently managed by delaying and/or reducing the scheduled dose, and as a consequence the efficacy of the treatment can be compromised.Since chemotherapy remains the cornerstone for treating many cancers, the development of compounds that inhibitmyelosuppressionwould provide considerable health benefits. By repurposing quizartinib we have identified a novel approach to managemyelosuppression, which led to the development of an effective treatment for a mouse model of acute myeloidleukemia(AML). Methods Quizartinib was administered to C57BL/6 mice by oral gavage with a single priming dose of 10 or 30 mg/kg. Fluorouracil (5-FU) was administered byintraperitonealinjection at 150 mg/kg 6-12 hours later. This schedule was repeated every 10 days to examine the protective effects of quizartinib from multiple cycles of 5-FU. The approach of quizartinib priming plus 5-FU every 10 days was examined as a treatment for a mouse model of AML. Results This work is based on studies from mice showing that a single dose of the FLT3 inhibitor quizartinib induces a rapid but transient quiescence of multipotentprogenitors (MPPs). MPPs are highly proliferative FLT3-expressing cells that are responsible for maintaining life-long blood production. They are markedly depleted by chemotherapy so their loss is a significant component of myelosuppression. We found that a single dose of quizartinib 6-12 hours before 5-FU resulted in a 10-fold increase in the survival of MPPs two days after administration. Quizartinib priming also provided significant protection to hematopoietic stem cells and committed progenitors within the lin-, Sca-1-, c-Kit+ population.Analysis of bone marrow at 2-10 days after a single 5-FU injection revealed the rapid recovery conferred to quizartinib-primed mice compared to mice primed with vehicle (Fig. 1). To test whether quizartinib provided protection from multiple cycles of 5-FU we injected mice once every 10 days with 5-FU following a priming dose of quizartinib or vehicle 12 hrsearlier. This 10-day cycle of 5-FU is a potent regimen that causes bone marrow failure and lethality. We found that quizartinib priming promoted a marked level of protection, with only 1 of 5 mice dying over a period of 15 cycles, whereas all vehicle-primed mice succumbed between the 4th and 6th cycles. In addition, we found that quizartinib-primed mice did not lose weight and showed a rapid recovery of white and red blood cells and platelets. From these findings we hypothesized that quizartinib priming before chemotherapy may provide a safe and effective approach for treating cancers that are independent of FLT3signaling. We tested this with an AML model developed from Npm1c x FLT3-ITD(F692L) mutant mice. The F692L mutation confers resistance to quizartinib. The suitability of this model was confirmed from experiments showing that quizartinib dosing did not induce quiescence of Npm1c x FLT3-ITD(F692L) AML cells, nor did it protect them from 5-FU. A cohort of non-irradiated B6.CD45.1 mice transplanted with Npm1c x FLT3-ITD(F692L) AML cells was therefore established. At 16 days after transplantation, when AML cells were evident in the peripheral blood, the mice were divided into three groups: (i) untreated, (ii) induction therapy treated, and (iii) quizartinib primed + 5-FU treated.The induction therapy involved two rounds ofcytarabineat 50 mg/kg for 5 days and doxorubicin at 1.5 mg/kg for 3 days (i.e. 5+3 therapy). All mice in the untreated and induction chemotherapy-treated groups succumbed within 30 and 56 days respectively (Fig. 2). In contrast, only 1 of 5 mice treated by 9 cycles of quizartinib priming + 5-FU succumbed (at day 121). The remaining 4 mice were healthy at 176 days after transplantation, and no AML cells were detectable in their blood or BM. Furthermore, surviving mice had WBC counts within the normal range. Conclusions This work has shownthat priming mice with quizartinib provides significant protection to the hematopoietic system from 5-FU cytotoxicity. This has resulted in the development of a novel quizartinib + 5-FU treatment protocol for a preclinical model of AML whereby it markedly enhanced the survival of mice compared to mice receiving conventional therapy. Disclosures No relevant conflicts of interest to declare.

scholarly journals Active Components from Cassia abbreviata Prevent HIV-1 Entry by Distinct Mechanisms of Action

2021 ◽  
Vol 22 (9) ◽  
pp. 5052
Author(s):  
Yue Zheng ◽  
Xian-Wen Yang ◽  
Dominique Schols ◽  
Mattia Mori ◽  
Bruno Botta ◽  
...  
Keyword(s):  
Crude Extract ◽  
Female Genital Tract ◽  
Binding Activity ◽  
Sub Saharan Africa ◽  
Active Components ◽  
Chemical Structures ◽  
3D Space ◽  
In Silico Study ◽  
Sub Saharan ◽  
Hiv 1

Cassia abbreviata is widely used in Sub-Saharan Africa for treating many diseases, including HIV-1 infection. We have recently described the chemical structures of 28 compounds isolated from an alcoholic crude extract of barks and roots ofC. abbreviata, and showed that six bioactive compounds inhibit HIV-1 infection. In the present study, we demonstrate that the six compounds block HIV-1 entry into cells: oleanolic acid, palmitic acid, taxifolin, piceatannol, guibourtinidol-(4α®8)-epiafzelechin, and a novel compound named as cassiabrevone. We report, for the first time, that guibourtinidol-(4α®8)-epiafzelechin and cassiabrevone inhibit HIV-1 entry (IC50 of 42.47 µM and 30.96 µM, respectively), as well as that piceatannol interacts with cellular membranes. Piceatannol inhibits HIV-1 infection in a dual-chamber assay mimicking the female genital tract, as well as HSV infection, emphasizing its potential as a microbicide. Structure-activity relationships (SAR) showed that pharmacophoric groups of piceatannol are strictly required to inhibit HIV-1 entry. By a ligand-based in silico study, we speculated that piceatannol and norartocarpetin may have a very similar mechanism of action and efficacy because of the highly comparable pharmacophoric and 3D space, while guibourtinidol-(4α®8)-epiafzelechin and cassiabrevone may display a different mechanism. We finally show that cassiabrevone plays a major role of the crude extract of CA by blocking the binding activity of HIV-1 gp120 and CD4.

Sign in / Sign up

Export Citation Format

Share Document