Isaac Jacob Kremsky

Dr. Isaac Jacob Kremsky


Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 August 2023 in Cells
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ESEvelyn S. Sanchez-Hernandez
Evelyn S. Sanchez-Hernandez
POPedro T. Ochoa
Pedro T. Ochoa
TSTise Suzuki
Tise Suzuki
Greisha L. Ortiz-HernandezGreisha L. Ortiz-Hernandez
Greisha L. Ortiz-Hernandez
JUJuli Unternaehrer
Juli Unternaehrer
CCCarlos A Casiano
Carlos A Casiano
Patients with advanced prostate cancer (PCa) invariably develop resistance to anti-androgen therapy and taxane-based chemotherapy. Glucocorticoid receptor (GR) has been implicated in PCa therapy resistance; however, the mechanisms underlying GR-mediated chemoresistance remain unclear. Lens epithelium-derived growth factor p75 (LEDGF/p75, also known as PSIP1 and DFS70) is a glucocorticoid-induced transcription co-activator implicated in cancer chemoresistance. We investigated the contribution of the GR–LEDGF/p75 axis to docetaxel (DTX)-resistance in PCa cells. GR silencing in DTX-sensitive and -resistant PCa cells decreased LEDGF/p75 expression, and GR upregulation in enzalutamide-resistant cells correlated with increased LEDGF/p75 expression. ChIP-sequencing revealed GR binding sites in the LEDGF/p75 promoter. STRING protein–protein interaction analysis indicated that GR and LEDGF/p75 belong to the same transcriptional network, and immunochemical studies demonstrated their co-immunoprecipitation and co-localization in DTX-resistant cells. The GR modulators exicorilant and relacorilant increased the sensitivity of chemoresistant PCa cells to DTX-induced cell death, and this effect was more pronounced upon LEDGF/p75 silencing. RNA-sequencing of DTX-resistant cells with GR or LEDGF/p75 knockdown revealed a transcriptomic overlap targeting signaling pathways associated with cell survival and proliferation, cancer, and therapy resistance. These studies implicate the GR–LEDGF/p75 axis in PCa therapy resistance and provide a pre-clinical rationale for developing novel therapeutic strategies for advanced PCa.

3 August 2023 in BMC Genomics
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Journal Article
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YJYoon Hee Jung
Yoon Hee Jung
HWHsiao-Lin V. Wang
Hsiao-Lin V. Wang
SASamir Ali
Samir Ali
VCVictor G. Corces
Victor G. Corces
IKIsaac Jacob Kremsky
Isaac Jacob Kremsky
CD-1 is an outbred mouse stock that is frequently used in toxicology, pharmacology, and fundamental biomedical research. Although inbred strains are typically better suited for such studies due to minimal genetic variability, outbred stocks confer practical advantages over inbred strains, such as improved breeding performance and low cost. Knowledge of the full genetic variability of CD-1 would make it more useful in toxicology, pharmacology, and fundamental biomedical research. We performed deep genomic DNA sequencing of CD-1 mice and used the data to identify genome-wide SNPs, indels, and germline transposable elements relative to the mm10 reference genome. We used multiple genome-wide sequencing data types and previously published CD-1 SNPs to validate our called variants. We used the called variants to construct a strain-specific CD-1 reference genome, which we show can improve mappability and reduce experimental biases from genome-wide sequencing data derived from CD-1 mice. Based on previously published ChIP-seq and ATAC-seq data, we find evidence that genetic variation between CD-1 mice can lead to alterations in transcription factor binding. We also identified a number of variants in the coding region of genes which could have effects on translation of genes. We have identified millions of previously unidentified CD-1 variants with the potential to confound studies involving CD-1. We used the identified variants to construct a CD-1-specific reference genome, which can improve accuracy and reduce bias when aligning genomics data derived from CD-1 mice.

Verified
Journal Article
Open access
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IKIsaac Jacob Kremsky
Isaac Jacob Kremsky
SASamir Ali
Samir Ali
SSSeta S
Seta S
JHJacob Holley
Jacob Holley
SJStephen Justinen
Stephen Justinen
XMXiao Wen “Vivien” Mao
Xiao Wen “Vivien” Mao
The demands of deep space pose a health risk to the central nervous system that has long been a concern when sending humans to space. While little is known about how spaceflight affects transcription spatially in the brain, a greater understanding of this process has the potential to aid strategies that mitigate the effects of spaceflight on the brain. Therefore, we performed GeoMx Digital Spatial Profiling of mouse brains subjected to either spaceflight or grounded controls. Four brain regions were selected: Cortex, Frontal Cortex, Corunu Ammonis I, and Dentate Gyrus. Antioxidants have emerged as a potential means of attenuating the effects of spaceflight, so we treated a subset of the mice with a superoxide dismutase mimic, MnTnBuOE-2-PyP 5+ (BuOE). Our analysis revealed hundreds of differentially expressed genes due to spaceflight in each of the four brain regions. Both common and region-specific transcriptomic responses were observed. Metabolic pathways and pathways sensitive to oxidative stress were enriched in the four brain regions due to spaceflight. These findings enhance our understanding of brain regional variation in susceptibility to spaceflight conditions. BuOE reduced the transcriptomic effects of spaceflight at a large number of genes, suggesting that this compound may attenuate oxidative stress-induced brain damage caused by the spaceflight environment.

Verified
Journal Article
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IKIsaac Jacob Kremsky
Isaac Jacob Kremsky
RPReyna Shai Pergerson
Reyna Shai Pergerson
SJStephen Justinen
Stephen Justinen
SSSeta S
Seta S
JWJeffrey Willey
Jeffrey Willey
XMXiao Wen “Vivien” Mao
Xiao Wen “Vivien” Mao
The development of eye pathology is a serious concern for astronauts who spend time in deep space. Microgravity is a major component of the spaceflight environment which could have adverse effects on ocular health. The use of centrifugation to exert forces that partially or fully mimic Earth-level gravity in space is a possible countermeasure to mitigate the effects of microgravity on the eye. Therefore, we subjected mice on the International Space Station (ISS) to microgravity (0 G) or artificial gravity by centrifugation at 0.33 G, 0.67 G, and 1 G, and then performed RNA sequencing (RNA-seq) on optic nerve and retinal tissue after returning them to Earth alive. We find that the microgravity environment induces transcriptomic changes in the optic nerve and retina consistent with an increased oxidative stress load, inflammation, apoptosis, and lipid metabolic stress. We also find that adding artificial gravity on board the ISS attenuates the transcriptomic response to microgravity in a dose-dependent manner. Such attenuation may effectively protect from and mitigate spaceflight-induced detrimental effects on ocular tissue.

15 July 2025 in BMC Research Notes
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CMClyde Eugene Makamure
Clyde Eugene Makamure
SJStephen Justinen
Stephen Justinen
DMDaniel E. Martínez
Daniel E. Martínez
DHDavid A. Hessinger
David A. Hessinger
IKIsaac Jacob Kremsky
Isaac Jacob Kremsky
Here we report initial observations and bioinformatics analysis suggesting that the sea anemone Diadumene lineata can be induced to age when cultured at 16oC. Inducible aging may make D. lineata a useful experimental model for aging studies. This research stemmed from a published study of D. lineata that did not involve or report on inducible aging. Anemones cultured at 16oC displayed several signs of aging not evident when cultured at room temperature (21oC), including the cessation of binary fission, growth to a much larger size, a progressive reduction in the consumption of prey, and ultimately, shriveling. Re-analysis of published RNA-seq data identified 2,824 differentially expressed putative genes in anemones cultured at 16oC vs. room temperature. Functional enrichment analysis of the differentially expressed genes is consistent with an aging phenotype at 16oC, and suggests that the 16oC anemones may undergo gametogenesis prior to the development of senescence. A significant increase in somatic single nucleotide polymorphisms also occurred at 16oC.

6 November 2025 in Diseases
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JMJANE MBITHE MUINDE
JANE MBITHE MUINDE
CYCelina Romi Yamauchi
Celina Romi Yamauchi
JCJoseph Cruz
Joseph Cruz
AMAlena Analeigh McQuarter
Alena Analeigh McQuarter
KMKyah Miller
Kyah Miller
SKSalma Khan
Salma Khan
Background: Ovarian cancer (OC) is the second most common gynecologic malignancy in the United States and remains the leading cause of death among cancers of the female reproductive system. Alarmingly, mortality rates have risen disproportionately among women of African ancestry compared to those of European or Asian descent. Identifying microRNA (miRNA) signatures that contribute to these disparities may enhance prognostic accuracy and inform personalized therapeutic strategies. Methods: In this study, we identified prognostic markers of overall survival in serous ovarian cancer (SOC) using data from The Cancer Genome Atlas (TCGA) and the Human Protein Atlas. Integrative bioinformatic analyses revealed three key prognostic genes—TIMP3 (Tissue Inhibitor of Metalloproteinases-3), BRAF (v-raf murine sarcoma viral oncogene homolog B), and ITGB1 (Integrin Beta-1)—as critical molecular determinants associated with survival in patients with SOC. Candidate miRNAs regulating these genes were predicted using TargetScanHuman v8.0, identifying a core regulatory set comprising miR-192, miR-30d, miR-16-5p, miR-143-3p, and miR-20a-5p. To validate their clinical relevance, formalin-fixed, paraffin-embedded (FFPE) and fresh SOC tumor samples were obtained from African American and Caucasian patients who underwent surgery at Loma Linda University (LLU) between 2010 and 2023. Results and Discussion: Among all these, ITGB1 (p = 0.00033), TIMP3 (p = 0.0035), and BRAF (p = 0.026) emerged as statistically significant predictors. Following total RNA extraction, cDNA synthesis, and quantitative reverse transcription PCR (qRT-PCR), the expression levels of these miRNAs and their target genes were quantified. In the LLU cohort, ITGB1 and TIMP3 were significantly upregulated in African American patients compared to Caucasian patients (p < 0.01 and p < 0.02, respectively). Among the miRNAs, miR-192-5p was particularly noteworthy, showing marginally differential expression in LLU samples (p = 0.0712) but strong statistical significance in the TCGA cohort (p = 0.00013), where elevated expression correlated with poorer overall survival (p = 0.021). Pathway enrichment and gene ontology analyses (miRTargetLink2.0, Enrichr) revealed interconnected regulatory networks linking miR-192, miR-16-5p, miR-143-3p, and miR-20a-5p to ITGB1; miR-143-3p/miR-145-5p to BRAF; and miR-16-5p and miR-30c/d to TIMP3. Conclusions: Collectively, these findings identify distinct miRNA–mRNA regulatory signatures—particularly the miR-192-5p–ITGB1/TIMP3 axis—as potential clinically relevant biomarkers that may contribute to racial disparities and disease progression in ovarian cancer.