Investigating the effects of chronic low-dose radiation exposure in the liver of a hypothermic zebrafish model.

Mankind's quest for a manned mission to Mars is placing increased emphasis on the development of innovative radio-protective countermeasures for long-term space travel. Hibernation confers radio-protective effects in hibernating animals, and this has led to the investigation of synthetic torpor to mitigate the deleterious effects of chronic low-dose-rate radiation exposure. Here we describe an induced torpor model we developed using the zebrafish. We explored the effects of radiation exposure on this model with a focus on the liver. Transcriptomic and behavioural analyses were performed. Radiation exposure resulted in transcriptomic perturbations in lipid metabolism and absorption, wound healing, immune response, and fibrogenic pathways. Induced torpor reduced metabolism and increased pro-survival, anti-apoptotic, and DNA repair pathways. Coupled with radiation exposure, induced torpor led to a stress response but also revealed maintenance of DNA repair mechanisms, pro-survival and anti-apoptotic signals. To further characterise our model of induced torpor, the zebrafish model was compared with hepatic transcriptomic data from hibernating grizzly bears (Ursus arctos horribilis) and active controls revealing conserved responses in gene expression associated with anti-apoptotic processes, DNA damage repair, cell survival, proliferation, and antioxidant response. Similarly, the radiation group was compared with space-flown mice revealing shared changes in lipid metabolism.

Muscle atrophy phenotype gene expression during spaceflight is linked to a metabolic crosstalk in both the liver and the muscle in mice.

Human expansion in space is hampered by the physiological risks of spaceflight. The muscle and the liver are among the most affected tissues during spaceflight and their relationships in response to space exposure have never been studied. We compared the transcriptome response of liver and quadriceps from mice on NASA RR1 mission, after 37 days of exposure to spaceflight using GSEA, ORA, and sparse partial least square-differential analysis. We found that lipid metabolism is the most affected biological process between the two organs. A specific gene cluster expression pattern in the liver strongly correlated with glucose sparing and an energy-saving response affecting high energy demand process gene expression such as DNA repair, autophagy, and translation in the muscle. Our results show that impaired lipid metabolism gene expression in the liver and muscle atrophy gene expression are two paired events during spaceflight, for which dietary changes represent a possible countermeasure.

PDGF Promotes Dermal Fibroblast Activation via a Novel Mechanism Mediated by Signaling Through MCHR1.

Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy and excessive fibrosis of the skin and internal organs. To this day, no effective treatments to prevent the progression of fibrosis exist, and SSc patients have disabilities and reduced life expectancy. The need to better understand pathways that drive SSc and to find therapeutic targets is urgent. RNA sequencing data from SSc dermal fibroblasts suggested that melanin-concentrating hormone receptor 1 (MCHR1), one of the G protein-coupled receptors regulating emotion and energy metabolism, is abnormally deregulated in SSc. Platelet-derived growth factor (PDGF)-BB stimulation upregulated MCHR1 mRNA and protein levels in normal human dermal fibroblasts (NHDF), and MCHR1 silencing prevented the PDGF-BB-induced expression of the profibrotic factors transforming growth factor beta 1 (TGFß1) and connective tissue growth factor (CTGF). PDGF-BB bound MCHR1 in membrane fractions of NHDF, and the binding was confirmed using surface plasmon resonance (SPR). MCHR1 inhibition blocked PDGF-BB modulation of intracellular cyclic adenosine monophosphate (cAMP). MCHR1 silencing in NHDF reduced PDGF-BB signaling. In summary, MCHR1 promoted the fibrotic response in NHDF through modulation of TGFß1 and CTGF production, intracellular cAMP levels, and PDGF-BB-induced signaling pathways, suggesting that MCHR1 plays an important role in mediating the response to PDGF-BB and in the pathogenesis of SSc. Inhibition of MCHR1 should be considered as a novel therapeutic strategy in SSc-associated fibrosis.

Long non-coding RNAs and their potential impact on diagnosis, prognosis, and therapy in prostate cancer: racial, ethnic, and geographical considerations.

INTRODUCTION: Advances in high-throughput sequencing have greatly advanced our understanding of long non-coding RNAs (lncRNAs) in a relatively short period of time. This has expanded our knowledge of cancer, particularly how lncRNAs drive many important cancer phenotypes via their regulation of gene expression. AREAS COVERED: Men of African descent are disproportionately affected by PC in terms of incidence, morbidity, and mortality. LncRNAs could serve as biomarkers to differentiate low-risk from high-risk diseases. Additionally, they may represent therapeutic targets for advanced and castrate-resistant cancer. We review current research surrounding lncRNAs and their association with PC. We discuss how lncRNAs can provide new insights and diagnostic biomarkers for African American men. Finally, we review advances in computational approaches that predict the regulatory effects of lncRNAs in cancer. EXPERT OPINION: PC diagnostic biomarkers that offer high specificity and sensitivity are urgently needed. PC specific lncRNAs are compelling as diagnostic biomarkers owing to their high tissue and tumor specificity and presence in bodily fluids. Recent studies indicate that PCA3 clinical utility might be restricted to men of European descent. Further work is required to develop lncRNA biomarkers tailored for men of African descent.

Mammalian and Invertebrate Models as Complementary Tools for Gaining Mechanistic Insight on Muscle Responses to Spaceflight.

Bioinformatics approaches have proven useful in understanding biological responses to spaceflight. Spaceflight experiments remain resource intensive and rare. One outstanding issue is how to maximize scientific output from a limited number of omics datasets from traditional animal models including nematodes, fruitfly, and rodents. The utility of omics data from invertebrate models in anticipating mammalian responses to spaceflight has not been fully explored. Hence, we performed comparative analyses of transcriptomes of soleus and extensor digitorum longus (EDL) in mice that underwent 37 days of spaceflight. Results indicate shared stress responses and altered circadian rhythm. EDL showed more robust growth signals and Pde2a downregulation, possibly underlying its resistance to atrophy versus soleus. Spaceflight and hindlimb unloading mice shared differential regulation of proliferation, circadian, and neuronal signaling. Shared gene regulation in muscles of humans on bedrest and space flown rodents suggest targets for mitigating muscle atrophy in space and on Earth. Spaceflight responses of C. elegans were more similar to EDL. Discrete life stages of D. melanogaster have distinct utility in anticipating EDL and soleus responses. In summary, spaceflight leads to shared and discrete molecular responses between muscle types and invertebrate models may augment mechanistic knowledge gained from rodent spaceflight and ground-based studies.

Induced Torpor as a Countermeasure for Low Dose Radiation Exposure in a Zebrafish Model.

The development of the Artemis programme with the goal of returning to the moon is spurring technology advances that will eventually take humans to Mars and herald a new era of interplanetary space travel. However, long-term space travel poses unique challenges including exposure to ionising radiation from galactic cosmic rays and potential solar particle events, exposure to microgravity and specific nutritional challenges arising from earth independent exploration. Ionising radiation is one of the major obstacles facing future space travel as it can generate oxidative stress and directly damage cellular structures such as DNA, in turn causing genomic instability, telomere shortening, extracellular-matrix remodelling and persistent inflammation. In the gastrointestinal tract (GIT) this can lead to leaky gut syndrome, perforations and motility issues, which impact GIT functionality and affect nutritional status. While current countermeasures such as shielding from the spacecraft can attenuate harmful biological effects, they produce harmful secondary particles that contribute to radiation exposure. We hypothesised that induction of a torpor-like state would confer a radioprotective effect given the evidence that hibernation extends survival times in irradiated squirrels compared to active controls. To test this hypothesis, a torpor-like state was induced in zebrafish using melatonin treatment and reduced temperature, and radiation exposure was administered twice over the course of 10 days. The protective effects of induced-torpor were assessed via RNA sequencing and qPCR of mRNA extracted from the GIT. Pathway and network analysis were performed on the transcriptomic data to characterise the genomic signatures in radiation, torpor and torpor + radiation groups. Phenotypic analyses revealed that melatonin and reduced temperature successfully induced a torpor-like state in zebrafish as shown by decreased metabolism and activity levels. Genomic analyses indicated that low dose radiation caused DNA damage and oxidative stress triggering a stress response, including steroidal signalling and changes to metabolism, and cell cycle arrest. Torpor attenuated the stress response through an increase in pro-survival signals, reduced oxidative stress via the oxygen effect and detection and removal of misfolded proteins. This proof-of-concept model provides compelling initial evidence for utilizing an induced torpor-like state as a potential countermeasure for radiation exposure.

The effects of rosiglitazone on the neonatal rat cardiomyocyte transcriptome: a temporal analysis.

Aim: The objective was to determine via high-throughput RNA sequencing the temporal effects of rosiglitazone (Avandia®) on the neonatal rat ventricular myocyte transcriptome. Materials & methods: Neonatal rat ventricular myocytes (NRVMs) were exposed to rosiglitazone in vitro. Meta analyses utilized temporal comparisons of 0.5 h control versus 0.5 h treatment, 0.5 h treatment versus 24 h treatment and 24 h treatment versus 48 h treatment. Results: Time dependent responses were observed. At 0.5 h, the PI3K-AKT signaling pathway was impacted. At 24 h endoplasmic reticulum activity and protein degradation were altered. At 48 h, oxytocin signaling was perturbed. Conclusion: The effects of rosiglitazone occured early and increased in magnitude over time. A protective molecular response was triggered at 24 h and maintained until 48 h. In parallel, a response that can cause cardiac damage was activated. Our findings suggest that rosiglitazone has deleterious effects.

Spaceflight influences gene expression, photoreceptor integrity, and oxidative stress-related damage in the murine retina.

Extended spaceflight has been shown to adversely affect astronaut visual acuity. The purpose of this study was to determine whether spaceflight alters gene expression profiles and induces oxidative damage in the retina. Ten week old adult C57BL/6 male mice were flown aboard the ISS for 35 days and returned to Earth alive. Ground control mice were maintained on Earth under identical environmental conditions. Within 38 (+/-4) hours after splashdown, mice ocular tissues were collected for analysis. RNA sequencing detected 600 differentially expressed genes (DEGs) in murine spaceflight retinas, which were enriched for genes related to visual perception, the phototransduction pathway, and numerous retina and photoreceptor phenotype categories. Twelve DEGs were associated with retinitis pigmentosa, characterized by dystrophy of the photoreceptor layer rods and cones. Differentially expressed transcription factors indicated changes in chromatin structure, offering clues to the observed phenotypic changes. Immunofluorescence assays showed degradation of cone photoreceptors and increased retinal oxidative stress. Total retinal, retinal pigment epithelium, and choroid layer thickness were significantly lower after spaceflight. These results indicate that retinal performance may decrease over extended periods of spaceflight and cause visual impairment.

Identification of a Subtype of Poorly Differentiated Invasive Ductal Carcinoma of the Breast Based on Vimentin and E-cadherin Expression.

OBJECTIVE: The use of molecular markers can identify a subgroup of tumors with distinct recurrence patterns. The present study aimed to characterize the immunohistochemical expression of vimentin (VIM), of E-cadherin (CDH1), and of cytokeratin 5 (CK5) in patients with invasive ductal carcinomas (IDCs). METHODS: We have constructed a tissue microarray (TMA) from 87 patients with IDC of the breast. Immunohistochemistry (IHC) was performed to study the expression of estrogen and progesterone receptors (ER and PgR), human epidermal growth factor receptor 2 (HER2), VIM, CDH1, CK5, and Ki67. The tumors were classified as luminal A and B (n = 39), HER2 enriched (n = 25), and triple-negative (TNBC) (n = 23), based on the IHC expression. RESULTS: We have observed that luminal A and B tumors lack the VIM+/CDH1-/low phenotype. This phenotype was observed in 16.5% of the HER2+ tumors and in 60% of the TNBC tumors (p = 0.0001). Out of a total of 20 TNBC tumors, the CK5 (basal-like marker) was positive in 11 of them. The VIM+/CDH1-/low phenotype was observed in 5 CK5+ TNBC tumors (45%) and in 7 out of 9 CK5- TNBC tumors (78%) (p = 0.02). The median Ki67 index in the VIM+/CDH1-/low tumors was 13.6 (range: 17.8-45.4) compared with 9.8 (range: 4.1-38.1) in other tumors (p = 0.0007). The presence of lymph node metastasis was less frequent in patients with VIM+/CDH1-/low tumors (23% versus 61%; X2 test; p = 0.01). CONCLUSION: Our findings suggest that the expression of VIM and CDH1 can identify a subset of IDCs of the breast with a mesenchymal phenotype associated with poor prognosis, high-grade lesion, and high mitotic index.

OBJETIVO: O uso de marcadores moleculares pode identificar subtipos tumorais com diferentes taxas de recidiva. O objetivo do presente estudo é caracterizar a expressão imunohistoquímica da vimentina (VIM), da E-caderina (CDH1) e de CK5 em pacientes com carcinoma ductal invasivo (CDI) da mama. MéTODOS: Utilizamos uma matriz de amostras teciduais (TMA, na sigla em inglês) de 87 pacientes com CDI da mama. Para avaliar a expressão dos receptores de estrogênio (RE) e receptores de progesterona (RP), HER2, VIM, CDH1, CK5 e Ki67, utilizamos imunohistoquímica. Os tumores foram classificados como luminal A e B (n = 39), HER2+ (n = 25) e triplo negativo (TNBC) (n = 23). RESULTADOS: Foi observado que tumores luminais A e B não expressaram o fenótipo VIM+/CDH1-/low. Este fenótipo foi observado em 16,5% dos tumores HER2+ e em 60% dos tumores TNBC (p = 0,0001). Dos 20 tumores TNBC, a CK5 (marcador de tumor basalóide) foi super expressa em 11 amostras. O fenótipo VIM+/CDH1-/low foi observado em 5 tumores CK5+ TNBC (45%) e em 7 dos 9 tumores CK5- TNBC (78%) (p = 0,02). A expressão média de Ki67 nos tumores VIM+/CDH1-/low foi 13.6 (amplitude de 17,8 a 45,4) comparado com 9,8 (amplitude de 4,1 a 38,1) nos outros tumores (p = 0,0007). A presença de metástase linfonodal foi menor em tumores com fenótipo VIM+/CDH1-/low (23% contra 61%; teste X2 ; p = 0,01). CONCLUSãO: Nossos achados sugerem que a expressão de VIM e CDH1 pode identificar um subtipo de CDI da mama com fenótipo mesenquimal associado a pior prognóstico, lesões de alto grau e alto índice mitótico.

ABCG2 is a potential marker of tumor-initiating cells in breast cancer.

The existence of tumor-initiating cells (TICs) within solid tumors has been hypothesized to explain tumor heterogeneity and resistance to cancer therapy. In breast cancer, the expression of CD44 and CD24 and the activity of aldehyde dehydrogenase 1 (ALDH1) can be used to selectively isolate a cell population enriched in TICs. However, the ideal marker to identify TICs has not been established. The aim of this study was to evaluate the expression of novel potential markers for TIC in breast carcinoma. We prospectively analyzed the expression of CD44, CD24, ABCG2, and CXCR4, and the activity of ALDH1 by using flow cytometry in 48 invasive ductal carcinomas from locally advanced and metastatic breast cancer patients who were administered primary chemotherapy. A mammosphere assay was employed in 30 samples. The relationship among flow cytometric analyses, ABCG2 gene expression, and clinical and pathological responses to therapy was analyzed. The GSE32646 database was analyzed in silico to identify genes associated with tumors with low and high ABCG2 expression. We observed that the presence of ABCG2(+) cells within the primary tumor was the only marker to predict the formation of mammospheres in vitro (R (2) = 0.15, p = 0.029). Quantitative polymerase chain reaction (qPCR) revealed a positive correlation between ABCG2 expression and the presence of ABCG2(+) cells within the primary tumor. The expression of ABCG2 was predictive of the response to neoadjuvant chemotherapy in our experiments and in the GSE32646 dataset (p = 0.04 and p = 0.002, respectively). The in silico analysis demonstrated that ABCG2(Up) breast cancer samples have a slower cell cycle and a higher expression of membrane proteins but a greater potential for chromosomal instability, metastasis, immune evasion, and resistance to hypoxia. Such genetic characteristics are compatible with highly aggressive and resistant tumors. Our results support the hypothesis that the presence of ABCG2(+) cells in breast carcinomas is a marker of resistance to chemotherapy, and based on in vitro assays and the genetic profile, we show, for the first time, that ABCG2 protein can be used as an independent marker for TIC identification in breast cancer.