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17
result(s) for
"Perera, Dimuthu"
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Endothelium-specific depletion of LRP1 improves glucose homeostasis through inducing osteocalcin
The vascular endothelium is present within metabolic organs and actively regulates energy metabolism. Here we show osteocalcin, recognized as a bone-secreted metabolic hormone, is expressed in mouse primary endothelial cells isolated from heart, lung and liver. In human osteocalcin promoter-driven green fluorescent protein transgenic mice, green fluorescent protein signals are enriched in endothelial cells lining aorta, small vessels and capillaries and abundant in aorta, skeletal muscle and eye of adult mice. The depletion of lipoprotein receptor-related protein 1 induces osteocalcin through a Forkhead box O -dependent pathway in endothelial cells. Whereas depletion of osteocalcin abolishes the glucose-lowering effect of low-density lipoprotein receptor-related protein 1 depletion, osteocalcin treatment normalizes hyperglycemia in multiple mouse models. Mechanistically, osteocalcin receptor-G protein-coupled receptor family C group 6 member A and insulin-like-growth-factor-1 receptor are in the same complex with osteocalcin and required for osteocalcin-promoted insulin signaling pathway. Therefore, our results reveal an endocrine/paracrine role of endothelial cells in regulating insulin sensitivity, which may have therapeutic implications in treating diabetes and insulin resistance through manipulating vascular endothelium.
The vascular endothelium contributes to metabolic regulation, however, the underlying mechanisms are not fully understood. Here the authors show that endothelial low-density lipoprotein receptor-related protein 1 regulates glucose homeostasis via osteocalcin expression.
Journal Article
BET proteolysis targeted chimera-based therapy of novel models of Richter Transformation-diffuse large B-cell lymphoma
2021
Richter Transformation (RT) develops in CLL as an aggressive, therapy-resistant, diffuse large B cell lymphoma (RT-DLBCL), commonly clonally-related (CLR) to the concomitant CLL. Lack of available pre-clinical human models has hampered the development of novel therapies for RT-DLBCL. Here, we report the profiles of genetic alterations, chromatin accessibility and active enhancers, gene-expressions and anti-lymphoma drug-sensitivity of three newly established, patient-derived, xenograft (PDX) models of RT-DLBCLs, including CLR and clonally-unrelated (CLUR) to concomitant CLL. The CLR and CLUR RT-DLBCL cells display active enhancers, higher single-cell RNA-Seq-determined mRNA, and protein expressions of IRF4, TCF4, and BCL2, as well as increased sensitivity to BET protein inhibitors. CRISPR knockout of IRF4 attenuated c-Myc levels and increased sensitivity to a BET protein inhibitor. Co-treatment with BET inhibitor or BET-PROTAC and ibrutinib or venetoclax exerted synergistic in vitro lethality in the RT-DLBCL cells. Finally, as compared to each agent alone, combination therapy with BET-PROTAC and venetoclax significantly reduced lymphoma burden and improved survival of immune-depleted mice engrafted with CLR-RT-DLBCL. These findings highlight a novel, potentially effective therapy for RT-DLBCL.
Journal Article
Therapeutically actionable signaling node to rescue AURKA driven loss of primary cilia in VHL-deficient cells
by
Talley, Tia
,
Stephan, Clifford
,
Park, Yong Sung
in
1-Phosphatidylinositol 3-kinase
,
631/80/86
,
631/80/86/2364
2021
Loss of primary cilia in cells deficient for the tumor suppressor
von Hippel Lindau
(
VHL
) arise from elevated Aurora Kinase A (AURKA) levels. VHL in its role as an E3 ubiquitin ligase targets AURKA for degradation and in the absence of
VHL
, high levels of AURKA result in destabilization of the primary cilium. We identified NVP-BEZ235, a dual PI3K/AKT and mTOR inhibitor, in an image-based high throughput screen, as a small molecule that restored primary cilia in
VHL
-deficient cells. We identified the ability of AKT to modulate AURKA expression at the transcript and protein level. Independent modulation of AKT and mTOR signaling decreased AURKA expression in cells confirming AURKA as a new signaling node downstream of the PI3K cascade. Corroborating these data, a genetic knockdown of
AKT
in cells deficient for
VHL
rescued the ability of these cells to ciliate. Finally, inhibition of AKT/mTOR using NVP-BEZ235 was efficacious in reducing tumor burden in a 786-0 xenograft model of renal cell carcinoma. These data highlight a previously unappreciated signaling node downstream of the AKT/mTOR pathway via AURKA that can be targeted in
VHL
-null cells to restore ciliogenesis.
Journal Article
Superior efficacy of co-targeting GFI1/KDM1A and BRD4 against AML and post-MPN secondary AML cells
2021
There is an unmet need to overcome nongenetic therapy-resistance to improve outcomes in AML, especially post-myeloproliferative neoplasm (MPN) secondary (s) AML. Studies presented describe effects of genetic knockout, degradation or small molecule targeted-inhibition of GFI1/LSD1 on active enhancers, altering gene-expressions and inducing differentiation and lethality in AML and (MPN) sAML cells. A protein domain-focused CRISPR screen in LSD1 (KDM1A) inhibitor (i) treated AML cells, identified BRD4, MOZ, HDAC3 and DOT1L among the codependencies. Our findings demonstrate that co-targeting LSD1 and one of these co-dependencies exerted synergistic in vitro lethality in AML and post-MPN sAML cells. Co-treatment with LSD1i and the JAKi ruxolitinib was also synergistically lethal against post-MPN sAML cells. LSD1i pre-treatment induced GFI1, PU.1 and CEBPα but depleted c-Myc, overcoming nongenetic resistance to ruxolitinib, or to BETi in post-MPN sAML cells. Co-treatment with LSD1i and BETi or ruxolitinib exerted superior in vivo efficacy against post-MPN sAML cells. These findings highlight LSD1i-based combinations that merit testing for clinical efficacy, especially to overcome nongenetic therapy-resistance in AML and post-MPN sAML.
Journal Article
Superior efficacy of cotreatment with BET protein inhibitor and BCL2 or MCL1 inhibitor against AML blast progenitor cells
2019
First-generation bromodomain extra-terminal protein (BETP) inhibitors (BETi) (e.g., OTX015) that disrupt binding of BETP BRD4 to chromatin transcriptionally attenuate AML-relevant progrowth and prosurvival oncoproteins. BETi treatment induces apoptosis of AML BPCs, reduces in vivo AML burden and induces clinical remissions in a minority of AML patients. Clinical efficacy of more potent BETis, e.g., ABBV-075 (AbbVie, Inc.), is being evaluated. Venetoclax and A-1210477 bind and inhibit the antiapoptotic activity of BCL2 and MCL1, respectively, lowering the threshold for apoptosis. BETi treatment is shown here to perturb accessible chromatin and activity of enhancers/promoters, attenuating MYC, CDK6, MCL1 and BCL2, while inducing BIM, HEXIM1, CDKN1A expressions and apoptosis of AML cells. Treatment with venetoclax increased MCL1 protein levels, but cotreatment with ABBV-075 reduced MCL1 and Bcl-xL levels. ABBV-075 cotreatment synergistically induced apoptosis with venetoclax or A-1210477 in patient-derived, CD34+ AML cells. Compared to treatment with either agent alone, cotreatment with ABBV-075 and venetoclax was significantly more effective in reducing AML cell-burden and improving survival, without inducing toxicity, in AML-engrafted immune-depleted mice. These findings highlight the basis of superior activity and support interrogation of clinical efficacy and safety of cotreatment with BETi and BCL2 or MCL1 inhibitor in AML.
Journal Article
Integrative metabolomics and transcriptomics analysis reveals novel therapeutic vulnerabilities in lung cancer
by
Patel, Tajhal D.
,
Gunaratne, Preethi H.
,
Yustein, Jason T.
in
Adenocarcinoma
,
adenocarcinoma of lung
,
Adenocarcinoma of Lung - genetics
2023
Background Non‐small cell lung cancer (NSCLC) comprises the majority (~85%) of all lung tumors, with lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC) being the most frequently diagnosed histological subtypes. Multi‐modal omics profiling has been carried out in NSCLC, but no studies have yet reported a unique metabolite‐related gene signature and altered metabolic pathways associated with LUAD and LUSC. Methods We integrated transcriptomics and metabolomics to analyze 30 human lung tumors and adjacent noncancerous tissues. Differential co‐expression was used to identify modules of metabolites that were altered between normal and tumor. Results We identified unique metabolite‐related gene signatures specific for LUAD and LUSC and key pathways aberrantly regulated at both transcriptional and metabolic levels. Differential co‐expression analysis revealed that loss of coherence between metabolites in tumors is a major characteristic in both LUAD and LUSC. We identified one metabolic onco‐module gained in LUAD, characterized by nine metabolites and 57 metabolic genes. Multi‐omics integrative analysis revealed a 28 metabolic gene signature associated with poor survival in LUAD, with six metabolite‐related genes as individual prognostic markers. Conclusions We demonstrated the clinical utility of this integrated metabolic gene signature in LUAD by using it to guide repurposing of AZD‐6482, a PI3Kβ inhibitor which significantly inhibited three genes from the 28‐gene signature. Overall, we have integrated metabolomics and transcriptomics analyses to show that LUAD and LUSC have distinct profiles, inferred gene signatures with prognostic value for patient survival, and identified therapeutic targets and repurposed drugs for potential use in NSCLC treatment. Integrated metabolomic and transcriptomic strategies in lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC) tumors. The transcriptomic and metabolomic data were integrated and enriched pathways were inferred. Integrated gene signatures were evaluated for tumor prognosis and drug repurposing.
Journal Article
Gut Microbial Changes Associated With Obesity in Youth With Type 1 Diabetes
2025
Abstract
Context
Obesity is prevalent in type 1 diabetes (T1D) and is problematic with higher risk for diabetes complications. It is unknown to what extent gut microbiome changes are associated with obesity and T1D.
Objective
This work aimed to describe the gut microbiome and microbial metabolite changes associated with obesity in T1D. We hypothesized statistically significant gut microbial and metabolite differences in lean T1D youth (body mass index [BMI]: 5%-<85%) vs those with obesity (BMI: ≥95%).
Methods
We analyzed stool samples for gut microbial (using metagenomic shotgun sequencing) and short-chain fatty acid (SCFA) differences in lean (n = 27) and obese (n = 21) T1D youth in a pilot study. The mean ± SD age was 15.3 ± 2.2 years, glycated hemoglobin A1c 7.8 ± 1.3%, diabetes duration 5.1 ± 4.4 years, 42.0% female, and 94.0% were White.
Results
Bacterial community composition showed between sample diversity differences (β-diversity) by BMI group (P = .013). There was a higher ratio of Prevotella to Bacteroides in the obese group (P = .0058). There was a differential distribution of significantly abundant taxa in either the lean or obese groups, including increased relative abundance of Prevotella copri, among other taxa in the obese group. Functional profiling showed an upregulation of branched-chain amino acid (BCAA) biosynthesis in the obese group and upregulation of BCAA degradation, tyrosine metabolism, and secondary bile acid biosynthesis in the lean group. Stool SCFAs were higher in the obese vs the lean group (P < .05 for all).
Conclusion
Our findings identify a gut microbiome and microbial metabolite signature associated with obesity in T1D. These findings could help identify gut microbiome–targeted therapies to manage obesity in T1D.
Journal Article
Optimal Parameters to Determine the Apparent Diffusion Coefficient in Diffusion Weighted Imaging via Simulation
by
Perera, Dimuthu
in
Physics
2016
Diffusion weighted (DW) Imaging is a non-invasive MR technique that provides information about the tissue microstructure using the diffusion of water molecules. The diffusion is generally characterized by the apparent diffusion coefficient (ADC) parametric map. The purpose of this study is to investigate in silico how the calculation of ADC is affected by image SNR, b-values, and the true tissue ADC. Also, to provide optimal parameter combination depending on the percentage accuracy and precision for prostate peripheral region cancer application. Moreover, to suggest parameter choices for any type of tissue, while providing the expected accuracy and precision. In this research DW images were generated assuming a mono-exponential signal model at two different b-values and for known true ADC values. Rician noise of different levels was added to the DWI images to adjust the image SNR. Using the two DWI images, ADC was calculated using a mono-exponential model for each set of b-values, SNR, and true ADC. 40,000 ADC data were collected for each parameter setting to determine the mean and the standard-deviation of the calculated ADC, as well as the percentage accuracy and precision with respect to the true ADC. The accuracy was calculated using the difference between known and calculated ADC. The precision was calculated using the standard-deviation of calculated ADC. The optimal parameters for a specific study was determined when both the percentage accuracy and precision were minimized. In our study, we simulated two true ADCs (ADC 0.00102 for tumor and 0.00180 mm2/s for normal prostate peripheral region tissue). Image SNR was varied from 2 to 100 and b-values were varied from 0 to 2000s/mm2. The results show that the percentage accuracy and percentage precision were minimized with image SNR. To increase SNR, 10 signal-averagings (NEX) were used considering the limitation in total scan time. The optimal NEX combination for tumor and normal tissue for prostate peripheral region was 1: 9. Also, the minimum percentage accuracy and percentage precision were obtained when low b-value is 0 and high b-value is 800 mm2/s for normal tissue and 1400 mm2/s for tumor tissue. Results also showed that for tissues with 1 x 10-3 < ADC < 2.1 x 10-3 mm 2/s the parameter combination at SNR = 20, b-value pair 0, 800 mm 2/s with NEX = 1:9 can calculate ADC with a percentage accuracy of less than 2% and percentage precision of 6-8%. Also, for tissues with 0.6 x 10-3 < ADC < 1.25 x 10-3 mm2 /s the parameter combination at SNR = 20, b-value pair 0, 1400 mm 2/s with NEX =1:9 can calculate ADC with a percentage accuracy of less than 2% and percentage precision of 6-8%.
Dissertation
A descriptive study of knowledge, beliefs and practices regarding osteoporosis among female medical school entrants in Sri Lanka
by
Atukorala, Inoshi
,
Perera, Wagawatta Liyanage Sugandhika Padmini
,
Ediriweera de Silva, Risni Erandie
in
Attitudes
,
Family Medicine
,
Females
2014
Background
Osteoporosis is a significant problem in rapidly ageing populations in Asian regions. It causes a significant personal and societal impact and increases the burden on health care services.
Objectives
Aim of this study is to determine the knowledge, beliefs and practices regarding osteoporosis among young females entering medical schools in Sri Lanka.
Methods
This is a descriptive cross sectional study conducted amongst 186 female medical school entrants of the Faculties of Medicine, Universities of Colombo and Kelaniya from September to December 2010. A self administered questionnaire was used to assess knowledge, beliefs and practices on osteoporosis, including a food frequency chart to assess the calcium intake.
Results
The mean age was 20.7 +/− 2.1 years. Majority of the participants (51.6%, n = 96) had an average score (40–60) on the knowledge test, while 40.8% (n = 76) had a poor score (<40). However, in depth knowledge on risk factors, and protective factors was lacking. Perceived susceptibility for osteoporosis was low with only 13.9% (n = 26) of women agreeing that their chances of getting osteoporosis are high. The mean calcium intake was 528 mg/day and only 18.8% (n = 35) of the participants achieved the Recommended Daily Allowances (RDA) for Calcium. Exercise was grossly inadequate in the majority and only 13.6%( n = 23) engaged in the recommended exercises. Only 3.8% (n =7) of the participants currently engaged in specific behaviours to improve bone health while 10.8% (n = 20) had thought of routinely engaging in such behaviours.
Conclusions
Although majority of participants had a modest level of knowledge on osteoporosis, there were gaps in their knowledge in relation to risk factors, protective factors and on the insidious nature of osteoporosis. Perceived susceptibility for osteoporosis was low. Practices towards preventing Osteoporosis were inadequate.
Journal Article