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result(s) for
"Nowak, Rebecca M."
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Preclinical Safety Assessment of the EBS-LASV Vaccine Candidate against Lassa Fever Virus
by
Wynn, Melissa
,
Gerardi, Cheryl S.
,
Nowak, Rebecca M.
in
attenuated vaccine
,
Biodistribution
,
Cloning
2024
There are currently no prophylactic vaccines licensed to protect against Lassa fever caused by Lassa virus (LASV) infection. The Emergent BioSolutions (EBS) vaccine candidate, EBS-LASV, is being developed for the prevention of Lassa fever. EBS-LASV is a live-attenuated recombinant Vesicular Stomatitis Virus (rVSV)-vectored vaccine encoding the surface glycoprotein complex (GPC) from LASV and has two attenuating vector modifications: a gene shuffle of the VSV N gene and a deletion of the VSV G gene. Preclinical studies were performed to evaluate EBS-LASV’s neurovirulence potential following intracranial (IC) injection and to determine the biodistribution and vector replication following intramuscular (IM) inoculation in mice. In addition, the potential EBS-LASV toxicity was assessed using repeated-dose IM EBS-LASV administration to rabbits. All mice receiving the IC injection of EBS-LASV survived, while mice administered the unattenuated control vector did not. The vaccine was only detected in the muscle at the injection site, draining lymph nodes, and the spleen over the first week following IM EBS-LASV injection in mice, with no detectable plasma viremia. No toxicity was observed in rabbits receiving a three-dose regimen of EBS-LASV. These studies demonstrate that EBS-LASV is safe when administered to animals and supported a first-in-human dose-escalation, safety, and immunogenicity clinical study.
Journal Article
Quadrivalent VesiculoVax vaccine protects nonhuman primates from viral-induced hemorrhagic fever and death
by
Mire, Chad E.
,
Gerardi, Cheryl S.
,
Feldmann, Heinz
in
Animals
,
Antibodies, Viral - immunology
,
Biomedical research
2020
Recent occurrences of filoviruses and the arenavirus Lassa virus (LASV) in overlapping endemic areas of Africa highlight the need for a prophylactic vaccine that would confer protection against all of these viruses that cause lethal hemorrhagic fever (HF). We developed a quadrivalent formulation of VesiculoVax that contains recombinant vesicular stomatitis virus (rVSV) vectors expressing filovirus glycoproteins and that also contains a rVSV vector expressing the glycoprotein of a lineage IV strain of LASV. Cynomolgus macaques were vaccinated twice with the quadrivalent formulation, followed by challenge 28 days after the boost vaccination with each of the 3 corresponding filoviruses (Ebola, Sudan, Marburg) or a heterologous contemporary lineage II strain of LASV. Serum IgG and neutralizing antibody responses specific for all 4 glycoproteins were detected in all vaccinated animals. A modest and balanced cell-mediated immune response specific for the glycoproteins was also detected in most of the vaccinated macaques. Regardless of the level of total glycoprotein-specific immune response detected after vaccination, all immunized animals were protected from disease and death following lethal challenges. These findings indicate that vaccination with attenuated rVSV vectors each expressing a single HF virus glycoprotein may provide protection against those filoviruses and LASV most commonly responsible for outbreaks of severe HF in Africa.
Journal Article
Template-assisted covalent modification underlies activity of covalent molecular glues
2024
Molecular glues are proximity-inducing small molecules that have emerged as an attractive therapeutic approach. However, developing molecular glues remains challenging, requiring innovative mechanistic strategies to stabilize neoprotein interfaces and expedite discovery. Here we unveil a
trans
-labeling covalent molecular glue mechanism, termed ‘template-assisted covalent modification’. We identified a new series of BRD4 molecular glue degraders that recruit CUL4
DCAF16
ligase to the second bromodomain of BRD4 (BRD4
BD2
). Through comprehensive biochemical, structural and mutagenesis analyses, we elucidated how pre-existing structural complementarity between DCAF16 and BRD4
BD2
serves as a template to optimally orient the degrader for covalent modification of DCAF16
Cys58
. This process stabilizes the formation of BRD4–degrader–DCAF16 ternary complex and facilitates BRD4 degradation. Supporting generalizability, we found that a subset of degraders also induces GAK–BRD4
BD2
interaction through
trans
-labeling of GAK. Together, our work establishes ‘template-assisted covalent modification’ as a mechanism for covalent molecular glues, which opens a new path to proximity-driven pharmacology.
Characterization of DCAF16-based BRD4 molecular glue degraders revealed a
trans
-labeling mechanism termed ‘template-assisted covalent modification’, which opens a new path for proximity-driven pharmacology.
Journal Article
Fractionated low-dose radiotherapy primes the tumor microenvironment for immunotherapy in a murine mesothelioma model
by
Nowak, Anna K.
,
Cook, Alistair M.
,
D’Alonzo, Rebecca A.
in
Animal models
,
Animals
,
Blood flow
2025
Combination immune checkpoint inhibitors (nivolumab and ipilimumab) are currently a first-line treatment for mesothelioma; however, not all patients respond. The efficacy of treatment is influenced by the tumor microenvironment. Murine mesothelioma tumors were irritated with various radiotherapy doses. Radiotherapy induced vasculature changes were monitored by power Doppler and photoacoustic ultrasound and analyzed via mixed-effects models. Tissue staining was used to investigate the immune cell infiltrate of tumors. The optimal radiotherapy schedule was combined with immune checkpoint inhibitors, and the survival of mice was analyzed. Using low-dose, low-fraction radiotherapy allowed favorable modification of the murine mesothelioma tumor microenvironment. Irradiating tumors with 2 Gy × 5 fractions significantly improved blood flow and reduced hypoxia, consequently increasing the presence of CD8
+
and regulatory T cells in the tumor. Understanding the transient nature of these changes is crucial for optimizing the timing of therapeutic delivery. The combination of radiotherapy with dual immunotherapy (anti-PD-1 plus anti-CTLA-4) proved highly curative when administered concurrently. A diminishing rate of cures was noted with an increasing delay between radiotherapy and subsequent immunotherapy. Concurrent low-dose, low-fraction radiotherapy emerges as a translatable approach for improving the efficacy of immune checkpoint inhibitors in patients.
Journal Article
Lymph node metastases in resected pancreatic ductal adenocarcinoma: predictors of disease recurrence and survival
by
Tseng, Jennifer F
,
Wolpin, Brian M
,
Nowak, Jonathan A
in
631/67/1504/1713
,
692/4028/67/1504/1713
,
Adenocarcinoma
2017
Background:
Few studies have simultaneously assessed the prognostic value of the multiple classification systems for lymph node (LN) metastases in resected pancreatic ductal adenocarcinoma (PDAC).
Methods:
In 600 patients with resected PDAC, we examined the association of LN parameters (AJCC 7th and 8th editions, LN ratio (LNR), and log odds of metastatic LN (LODDS)) with pattern of recurrence and patient survival using logistic regression and Cox proportional hazards regression, respectively. Regression models adjusted for age, sex, margin status, tumour grade, and perioperative therapy.
Results:
Lymph node metastases classified by AJCC 7th and 8th editions, LNR, and LODDS were associated with worse disease free-survival (DFS) and overall survival (OS) (all
P
trend
<0.01). American Joint Committee on Cancer 8th edition effectively predicted DFS and OS, while minimising model complexity. Lymph node metastases had weaker prognostic value in patients with positive margins and distal resections (both
P
interaction
<0.03). Lymph node metastases by AJCC 7th and 8th editions did not predict the likelihood of local disease as the first site of recurrence.
Conclusions:
American Joint Committee on Cancer 8th edition LN classification is an effective and practical tool to predict outcomes in patients with resected PDAC. However, the prognostic value of LN metastases is attenuated in patients with positive resection margins and distal pancreatectomies.
Journal Article
Male Circumcision for the Prevention of HSV-2 and HPV Infections and Syphilis
by
Moulton, Lawrence H
,
Gray, Ronald H
,
Oliver, Amy E
in
Adolescent
,
Adult
,
Biological and medical sciences
2009
Male circumcision has been shown to reduce the acquisition of the human immunodeficiency virus (HIV) in circumcised men. In two studies in Uganda involving 3393 adolescent boys and men who were seronegative for HIV and for herpes simplex virus type 2 (HSV-2), circumcision reduced the acquisition of HSV-2 and the prevalence of high-risk human papillomavirus (HPV) infection but not the acquisition of syphilis.
In two studies in Uganda, circumcision reduced the acquisition of herpes simplex virus type 2 (HSV-2) and the prevalence of high-risk human papillomavirus (HPV) infection but not the acquisition of syphilis.
Herpes simplex virus type 2 (HSV-2) and human papillomavirus (HPV) infections and syphilis are common sexually transmitted infections. HSV-2 infection and syphilis are two of the main causes of genital ulceration
1
–
3
and have been associated with an increased risk of human immunodeficiency virus (HIV) infection in observational studies.
1
,
2
,
4
The prevalence of HPV is significantly increased in developing nations.
5
HPV infection can cause genital warts, and high-risk HPV genotypes are associated with penile and anal cancer, as well as with cervical cancer in female partners.
5
,
6
Three randomized trials and multiple observational studies showed that male circumcision significantly . . .
Journal Article
Oral sex practices among men who have sex with men and transgender women at risk for and living with HIV in Nigeria
2020
Men who have sex with men (MSM) and transgender women (TGW) are at risk for sexually transmitted infections (STIs), including those of the oropharynx. We estimated the prevalence and factors associated with oral sex practices and characterized oropharyngeal STIs among a cohort of MSM and TGW in Nigeria.
From 2013 to 2018, TRUST/RV368 recruited MSM and TGW into HIV/STI diagnosis and treatment at community-based clinics in Nigeria. Participants who completed HIV testing and oral sex questions at enrollment were selected. Cross-sectional analyses with bivariate and multivariable logistic regression models estimated odds ratios (ORs) and 95% confidence intervals (CIs). Oropharyngeal swab testing for Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) began in 2014 and for those with diagnostic results at enrollment, the unadjusted association of oral sex practices with oropharyngeal STIs was conducted.
A total of 1342 participants had a median age of 25 years (interquartile range: 22-29), 58% were living with HIV, and 69% reported oral sex practices. Factors associated with increased odds of engaging in oral sex included living with HIV (adjusted [a]OR: 1.4, 95% CI: 1.1-1.8), self-identifying as a woman (aOR:1.8, 95% CI: 1.1-2.8), mobile phone ownership (aOR:2.3, 95% CI: 1.3-3.9), receptive anal sex (aOR:1.7, 95% CI:1.3-2.3) and multiple male sexual partners (2 to 4 vs. ≤1, aOR:1.5, 95% CI: 1.0-2.2; 5+ vs ≤1, aOR:2.9, 95% CI:1.9-4.3). Oropharyngeal STI prevalence was 7% (52/752) and higher among those who engaged in oral sex compared to those who did not (unadjusted OR: 2.5, 95% CI:1.2-5.3).
Oral sex was common and associated with an increased odds of oropharyngeal STIs among MSM and TGW from Nigeria. In the absence of screening and treatment guidelines, condoms continue to be the mainstay for oral STI prevention. A pre-exposure prophylaxis for bacterial STIs would complement current prevention strategies to curb transmission.
Journal Article
Facilitator and barrier perspectives on learning and implementing high-resolution anoscopy in Abuja, Nigeria: a qualitative study
2025
Background
Early detection and treatment of anal precancer via high resolution anoscopy (HRA) is paramount to prevent anal cancer, particularly for populations at heightened risk like sexual minority men (SMM) living with HIV. Successful training and sustainability of cancer screening requires attention to local contexts, best captured by qualitative research. Using the Consolidated Framework for Implementation Research (CFIR), this study investigated factors that challenged or fostered learning and implementing HRA across a variety of stakeholder groups in Abuja, Nigeria.
Methods
Using in-depth qualitative methodology, nineteen semi-structured interviews were conducted in September 2023 with stakeholders - patients who underwent HRA, HRA providers, and health system representatives in Nigeria. Thematic analysis, guided by CFIR, was employed to identify key themes related to the barriers and facilitators to practicing HRA as guided by the International Anal Neoplasia Society.
Results
Eight themes were identified across three domains. Barriers included low knowledge and understanding of HRA, with participants explicitly noting the need for more research in low resource settings to garner local acceptance. Participants were concerned about financial costs for the clinic and the patients. Facilitators included organizational buy-in, SMM social networks, and a safe clinic environment to support HRA engagement. Facilitators important for sustainability included acceptance of the research evidence for HRA and recognition of the health benefits. Overall, participants from all stakeholder groups welcomed HRA as a new evidence-based intervention as part of HIV care services.
Conclusions
Our study highlighted the need for localized research, cultural sensitivity, and resource allocation to improve the adoption of HRA in a Nigerian HIV care setting. Organizational buy-in, community engagement, and safe healthcare environments facilitated trust and patient engagement and would promote long term sustainability. Overall, the study provided perspectives from various stakeholders that strengthen clinical proficiency and sustainability of anal cancer screening in Nigeria.
Journal Article
Trace Organic Gas Analyzer Time-of-Flight mass spectrometer (TOGA-TOF) system for airborne observations of formaldehyde
2026
Formaldehyde (HCHO) is a ubiquitous atmospheric constituent, originating from primary emissions (natural and anthropogenic) and secondary production via the oxidation of volatile organic compounds (VOCs). In addition to being a regulated pollutant, HCHO is a key species used as a tracer of recent photochemical activity due to its short atmospheric lifetime and its role as a source of HOx radicals. Given its diverse sources and high spatial variability, HCHO is challenging to represent accurately in chemical transport models, often resulting in significant discrepancies with observations. Airborne in situ measurements of HCHO, especially when combined with VOC precursor data, offer valuable insights into its atmospheric distributions for evaluating models. Here, we present HCHO observations from the NSF NCAR Trace Organic Gas Analyzer with Time-of-Flight mass spectrometer (TOGA-TOF), deployed during the 2019 Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign. While most HCHO instruments target at most a few selected species for measurement, the TOGA-TOF employs a rapid gas chromatography-mass spectrometry (GC/MS) technique and provides discrete VOC measurements – including >100 C1–C10 species – at a time resolution of less than 2 min. We compare TOGA-TOF HCHO data to measurements from three 1 Hz instruments aboard the NASA DC-8: the Compact Atmospheric Multi-species Spectrometer (CAMS), the In Situ Airborne Formaldehyde (ISAF) instrument, and a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS). The wide dynamic range of observed HCHO concentrations (from <100 ppt to ∼ 100 ppb) during FIREX-AQ enabled a robust intercomparison. TOGA-TOF HCHO agreed well with CAMS (slope = 1.1), with similar agreement with the PTR-ToF-MS, while larger discrepancies were observed with ISAF (slope = 1.5), likely due to differences in calibrations. Normalized excess mixing ratios (NEMRs) of HCHO relative to CO in wildfire plumes exhibited consistent trends with plume age across instruments. These findings highlight the TOGA-TOF's capability for highly sensitive and accurate airborne HCHO measurements.
Journal Article
Effects of Obesity and Metabolic Syndrome on Steroidogenesis and Folliculogenesis in the Female Ossabaw Mini-Pig
by
Nowak, Romana A.
,
Newell-Fugate, Annie E.
,
Krisher, Rebecca L.
in
3-Hydroxysteroid Dehydrogenases - genetics
,
3-Hydroxysteroid Dehydrogenases - metabolism
,
Analysis
2015
The discrete effects of obesity on infertility in females remain undefined to date. To investigate obesity-induced ovarian dysfunction, we characterized metabolic parameters, steroidogenesis, and folliculogenesis in obese and lean female Ossabaw mini-pigs. Nineteen nulliparous, sexually mature female Ossabaw pigs were fed a high fat/cholesterol/fructose diet (n=10) or a control diet (n=9) for eight months. After a three-month diet-induction period, pigs remained on their respective diets and had ovarian ultrasound and blood collection conducted during a five-month study period after which ovaries were collected for histology, cell culture, and gene transcript level analysis. Blood was assayed for steroid and protein hormones. Obese pigs developed abdominal obesity and metabolic syndrome, including hyperglycemia, hypertension, insulin resistance and dyslipidemia. Obese pigs had elongated estrous cycles and hyperandrogenemia with decreased LH, increased FSH and luteal phase progesterone, and increased numbers of medium, ovulatory, and cystic follicles. Theca cells of obese, compared to control, pigs displayed androstenedione hypersecretion in response to in vitro treatment with LH, and up-regulated 3-beta-hydroxysteroid dehydrogenase 1 and 17-beta-hydroxysteroid dehydrogenase 4 transcript levels in response to in vitro treatment with LH or LH + insulin. Granulosa cells of obese pigs had increased 3-beta-hydroxysteroid dehydrogenase 1 transcript levels. In summary, obese Ossabaw pigs have increased transcript levels and function of ovarian enzymes in the delta 4 steroidogenic pathway. Alterations in LH, FSH, and progesterone, coupled with theca cell dysfunction, contribute to the hyperandrogenemia and disrupted folliculogenesis patterns observed in obese pigs. The obese Ossabaw mini-pig is a useful animal model in which to study the effects of obesity and metabolic syndrome on ovarian function and steroidogenesis. Ultimately, this animal model may be useful toward the development of therapies to improve fertility in obese and/or hyperandrogenemic females or in which to examine the effects of obesity on the maternal-fetal environment and offspring health.
Journal Article