Fatty acid binding protein 5 inhibition attenuates pronociceptive cytokine/chemokine expression and suppresses osteoarthritis pain: A comparative human and rat study.

OBJECTIVE: Osteoarthritis (OA) is often accompanied by debilitating pain that is refractory to available analgesics due in part to the complexity of signaling molecules that drive OA pain and our inability to target these in parallel. Fatty acid binding protein 5 (FABP5) is a lipid chaperone that regulates inflammatory pain; however, its contribution to OA pain has not been characterized. DESIGN: This combined clinical and pre-clinical study utilized synovial tissues obtained from subjects with end-stage OA and rats with monoiodoacetate-induced OA. Cytokine and chemokine release from human synovia incubated with a selective FABP5 inhibitor was profiled with cytokine arrays and ELISA. Immunohistochemical analyses were conducted for FABP5 in human and rat synovium. The efficacy of FABP5 inhibitors on pain was assessed in OA rats using incapacitance as an outcome. RNA-seq was then performed to characterize the transcriptomic landscape of synovial gene expression in OA rats treated with FABP5 inhibitor or vehicle. RESULTS: FABP5 was expressed in human synovium and FABP5 inhibition reduced the secretion of pronociceptive cytokines (interleukin-6 [IL6], IL8) and chemokines (CCL2, CXCL1). In rats, FABP5 was upregulated in the OA synovium and its inhibition alleviated incapacitance. The transcriptome of the rat OA synovium exhibited >6000 differentially expressed genes, including the upregulation of numerous pronociceptive cytokines and chemokines. FABP5 inhibition blunted the upregulation of the majority of these pronociceptive mediators. CONCLUSIONS: FABP5 is expressed in the OA synovium and its inhibition suppresses pronociceptive signaling and pain, indicating that FABP5 inhibitors may constitute a novel class of analgesics to treat OA.

Fatty acid binding protein 5 regulates docetaxel sensitivity in taxane-resistant prostate cancer cells.

Prostate cancer is a leading cause of cancer-related deaths in men in the United States. Although treatable when detected early, prostate cancer commonly transitions to an aggressive castration-resistant metastatic state. While taxane chemotherapeutics such as docetaxel are mainstay treatment options for prostate cancer, taxane resistance often develops. Fatty acid binding protein 5 (FABP5) is an intracellular lipid chaperone that is upregulated in advanced prostate cancer and is implicated as a key driver of its progression. The recent demonstration that FABP5 inhibitors produce synergistic inhibition of tumor growth when combined with taxane chemotherapeutics highlights the possibility that FABP5 may regulate other features of taxane function, including resistance. Employing taxane-resistant DU145-TXR cells and a combination of cytotoxicity, apoptosis, and cell cycle assays, our findings demonstrate that FABP5 knockdown sensitizes the cells to docetaxel. In contrast, docetaxel potency was unaffected by FABP5 knockdown in taxane-sensitive DU145 cells. Taxane-resistance in DU145-TXR cells stems from upregulation of the P-glycoprotein ATP binding cassette subfamily B member 1 (ABCB1). Expression analyses and functional assays confirmed that FABP5 knockdown in DU145-TXR cells markedly reduced ABCB1 expression and activity, respectively. Our study demonstrates a potential new function for FABP5 in regulating taxane sensitivity and the expression of a major P-glycoprotein efflux pump in prostate cancer cells.

Biallelic loss of function variants in WBP4, encoding a spliceosome protein, result in a variable neurodevelopmental delay syndrome.

Over two dozen spliceosome proteins are involved in human diseases, also referred to as spliceosomopathies. WBP4 (WW Domain Binding Protein 4) is part of the early spliceosomal complex, and was not described before in the context of human pathologies. Ascertained through GeneMatcher we identified eleven patients from eight families, with a severe neurodevelopmental syndrome with variable manifestations. Clinical manifestations included hypotonia, global developmental delay, severe intellectual disability, brain abnormalities, musculoskeletal and gastrointestinal abnormalities. Genetic analysis revealed overall five different homozygous loss-of-function variants in WBP4. Immunoblotting on fibroblasts from two affected individuals with different genetic variants demonstrated complete loss of protein, and RNA sequencing analysis uncovered shared abnormal splicing patterns, including enrichment for abnormalities of the nervous system and musculoskeletal system genes, suggesting that the overlapping differentially spliced genes are related to the common phenotypes of the probands. We conclude that biallelic variants in WBP4 cause a spliceosomopathy. Further functional studies are called for better understanding of the mechanism of pathogenicity.

Monoacylglycerol Lipase and Cyclooxygenase-2 Expression in Osteoarthritic Human Knees.

Background: Osteoarthritis (OA) is a progressive degenerative joint disease that presents with significant pain and functional disability. The endocannabinoid 2-arachidonoylglycerol activates cannabinoid receptors to reduce pain while its hydrolysis by the enzyme monoacylglycerol lipase (MAGL) generates arachidonic acid, the direct precursor to proalgesic eicosanoids synthesized by cyclooxygenase-2 (COX-2), highlighting the potential for crosstalk between MAGL and COX-2. While COX-2 expression in human OA cartilage has been described, the distribution of MAGL in knee osteochondral tissue has not been reported and was the goal of the current study. Methods: MAGL and COX-2 expression in International Cartilage Repair Society grade II and grade IV knee osteochondral tissue obtained from male and female subjects with OA was investigated through immunohistochemistry. Immunolocalization of both proteins was investigated within articular cartilage and subchondral bone. Results: MAGL is expressed throughout the cartilage of grade II arthritic tissue, with prominent distribution in the superficial and deep zones. Elevated expression of MAGL was evident in grade IV samples, with additional distribution observed in subchondral bone. COX-2 expression followed a similar pattern, with uniform distribution in cartilage and increased expression in grade IV tissue. Conclusions: This study establishes MAGL expression in arthritic cartilage and subchondral bone of subjects with OA. The proximity between MAGL and COX-2 suggests the potential for crosstalk between endocannabinoid hydrolysis and eicosanoid signaling in the maintenance of OA pain.

FABP5 Inhibition against PTEN-Mutant Therapy Resistant Prostate Cancer.

Resistance to standard of care taxane and androgen deprivation therapy (ADT) causes the vast majority of prostate cancer (PC) deaths worldwide. We have developed RapidCaP, an autochthonous genetically engineered mouse model of PC. It is driven by the loss of PTEN and p53, the most common driver events in PC patients with life-threatening diseases. As in human ADT, surgical castration of RapidCaP animals invariably results in disease relapse and death from the metastatic disease burden. Fatty Acid Binding Proteins (FABPs) are a large family of signaling lipid carriers. They have been suggested as drivers of multiple cancer types. Here we combine analysis of primary cancer cells from RapidCaP (RCaP cells) with large-scale patient datasets to show that among the 10 FABP paralogs, FABP5 is the PC-relevant target. Next, we show that RCaP cells are uniquely insensitive to both ADT and taxane treatment compared to a panel of human PC cell lines. Yet, they share an exquisite sensitivity to the small-molecule FABP5 inhibitor SBFI-103. We show that SBFI-103 is well tolerated and can strongly eliminate RCaP tumor cells in vivo. This provides a pre-clinical platform to fight incurable PC and suggests an important role for FABP5 in PTEN-deficient PC.

Acute postoperative pain and dorsal root ganglia transcriptomic signatures following total knee arthroplasty (TKA) in rats: An experimental study.

Total knee arthroplasty (TKA) is the final treatment option for patients with advanced knee osteoarthritis (OA). Unfortunately, TKA surgery is accompanied by acute postoperative pain that is more severe than arthroplasty performed in other joints. Elucidating the molecular mechanisms specific to post-TKA pain necessitates an animal model that replicates clinical TKA procedures, induces acute postoperative pain, and leads to complete functional recovery. Here, we present a new preclinical TKA model in rats and report on functional and behavioral outcomes indicative of pain, analgesic efficacy, serum cytokine levels, and dorsal root ganglia (DRG) transcriptomes during the acute postoperative period. Following TKA, rats exhibited marked deficits in weight bearing that persisted for 28 days. Home cage locomotion, rearing, and gait were similarly impacted and recovered by day 14. Cytokine levels were elevated on postoperative days one and/or two. Treatment with morphine, ketorolac, or their combination improved weight bearing while gabapentin lacked efficacy. When TKA was performed in rats with OA, similar functional deficits and comparable recovery time courses were observed. Analysis of DRG transcriptomes revealed upregulation of transcripts linked to multiple molecular pathways including inflammation, MAPK signaling, and cytokine signaling and production. In summary, we developed a clinically relevant rat TKA model characterized by resolution of pain and functional recovery within five weeks and with pain-associated behavioral deficits that are partially alleviated by clinically administered analgesics, mirroring the postoperative experience of TKA patients.

Governing COVID-19: analyzing the effects of policy responses on food systems in Tanzania.

Background: The outbreak of the COVID-19 pandemic increased debates on global public health concerns. From early 2020 to 2022, globally, life was upended in the wake of the pandemic. Industries of all kinds were forced to rapidly changed how they work, including agriculture. Particularly for smallholder farmers in developing countries, the COVID-19 pandemic, coupled with climate change effects, negatively affected their livelihoods. Achieving the UN Sustainable Development Goals by 2030 is unrealistic if immediate efforts are not made to address the existential threats facing smallholder farmers. This study analyzes COVID-19 governance and policy responses, examining its effects on smallholder farmers in the south and east of Tanzania using both qualitative and quantitative techniques. Results: Findings show that mobility restrictions imposed by other countries and fears of the Tanzanian people leading to voluntary isolation resulted in an amended structure of farmers' markets: Reductions in exports, imports and in the purchasing power of the local people followed. Food security was diminished as food availability on the market level was reduced due to mobility restrictions. The impact of COVID-19 resulted in more than 85% of smallholder farmers experiencing an income reduction, thus also increasing the pre-existing vulnerability of these communities. Findings show that farms producing non-exported crops had less severe income reductions and could cope better. The results indicate that only 20% of smallholder farmers started using digital information technology to gather information since physical movements were restricted. Access to technology remained limited in rural areas. Even during the COVID-19 crises, farmers' concerns about the vulnerability of their food systems include non-COVID-19 causes, such as climate change. Conclusions: Although Tanzania did not impose a total lockdown, the country was affected by COVID-19, partly via policies of other countries. Impacts included: (i) a decline in local markets as smallholder farmers had fewer trading partners from neighboring states; (ii) a loss of employment opportunities due to the absence of both local and external trade; (iii) reductions of farm output and income; (iv) a lack of agricultural inputs (fertilizer etc.) that are usually imported; (v) fear to continue farming activities due to news about COVID-19 spreading; and (vi) reduction of work efficiency because of a lack of social gathering due to voluntary isolation.While COVID-19 compelled policymakers to make urgent decisions to ensure stable food supply chains, the fundamental task is to address these immediate disruptions while also investing in the long-term goal of a resilient, sustainable, and productive global food system. This can be achieved by adopting a policy package that includes investments in technological development, access to small long-term loans, and regulatory reforms, with which governments can create conditions supporting productive, sustainable, and resilient food systems that can withstand future shocks.

FABP5 deletion in nociceptors augments endocannabinoid signaling and suppresses TRPV1 sensitization and inflammatory pain.

The endocannabinoid anandamide (AEA) produces antinociceptive effects by activating cannabinoid receptor 1 (CB1). However, AEA also serves as an agonist at transient receptor potential vanilloid receptor 1 (TRPV1) in nociceptive sensory neurons, which may exacerbate pain. This potential functional duality is highlighted by the failure of an inhibitor of the AEA catabolic enzyme fatty acid amide hydrolase (FAAH) to afford pain relief in a clinical trial. Consequently, it remains to be determined whether elevating AEA levels in nociceptors leads to antinociceptive or pro-nociceptive effects. Fatty acid binding protein 5 (FABP5) is an intracellular carrier that mediates AEA transport to FAAH for inactivation. Leveraging the abundant expression of FABP5 in TRPV1+ nociceptors, we employed a conditional knockout strategy to demonstrate that FABP5 deletion in nociceptors augments AEA levels, resulting in the emergence of antinociceptive effects mediated by CB1. Mechanistically, FABP5 deletion suppresses inflammation- and nerve growth factor-mediated TRPV1 sensitization via CB1, an effect mediated by calcineurin. Unexpectedly, inhibition of FAAH failed to blunt TRPV1 sensitization, uncovering functionally distinct outputs resulting from FABP5 and FAAH inhibition. Collectively, our results demonstrate that FABP5 serves a key role in governing endocannabinoid signaling in nociceptors to disrupt TRPV1 sensitization and pain, and position FABP5 as a therapeutic target for the development of analgesics.

Pharmaceutical pollution of the world's rivers.

Environmental exposure to active pharmaceutical ingredients (APIs) can have negative effects on the health of ecosystems and humans. While numerous studies have monitored APIs in rivers, these employ different analytical methods, measure different APIs, and have ignored many of the countries of the world. This makes it difficult to quantify the scale of the problem from a global perspective. Furthermore, comparison of the existing data, generated for different studies/regions/continents, is challenging due to the vast differences between the analytical methodologies employed. Here, we present a global-scale study of API pollution in 258 of the world's rivers, representing the environmental influence of 471.4 million people across 137 geographic regions. Samples were obtained from 1,052 locations in 104 countries (representing all continents and 36 countries not previously studied for API contamination) and analyzed for 61 APIs. Highest cumulative API concentrations were observed in sub-Saharan Africa, south Asia, and South America. The most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing. The most frequently detected APIs were carbamazepine, metformin, and caffeine (a compound also arising from lifestyle use), which were detected at over half of the sites monitored. Concentrations of at least one API at 25.7% of the sampling sites were greater than concentrations considered safe for aquatic organisms, or which are of concern in terms of selection for antimicrobial resistance. Therefore, pharmaceutical pollution poses a global threat to environmental and human health, as well as to delivery of the United Nations Sustainable Development Goals.

Intercellular delivery of therapeutic oligonucleotides.

One promising approach to cancer therapeutics is to induce changes in gene expression that either reduce cancer cell proliferation or induce cancer cell death. Therefore, delivering oligonucleotides (siRNA/miRNA) that target specific genes or gene programs might have a potential therapeutic benefit. The aim of this study was to examine the potential of cell-based delivery of oligonucleotides to cancer cells via two naturally occurring intercellular pathways: gap junctions and vesicular/exosomal traffic. We utilized human mesenchymal stem cells (hMSCs) as delivery cells and chose to deliver in vitro two synthetic oligonucleotides, AllStars HS Cell Death siRNA and miR-16 mimic, as toxic (therapeutic) oligonucleotides targeting three cancer cell lines: prostate (PC3), pancreatic (PANC1) and cervical (HeLa). Both oligonucleotides dramatically reduced cell proliferation and/or induced cell death when transfected directly into target cells and delivery hMSCs. The delivery and target cells we chose express gap junction connexin 43 (Cx43) endogenously (PC3, PANC1, hMSC) or via stable transfection (HeLaCx43). Co-culture of hMSCs (transfected with either toxic oligonucleotide) with any of Cx43 expressing cancer cells induced target cell death (~20% surviving) or senescence (~85% proliferation reduction) over 96 hours. We eliminated gap junction-mediated delivery by using connexin deficient HeLaWT cells or knocking out endogenous Cx43 in PANC1 and PC3 cells via CRISPR/Cas9. Subsequently, all Cx43 deficient target cells co-cultured with the same toxic oligonucleotide loaded hMSCs proliferated, albeit at significantly slower rates, with cell number increasing on average ~2.2-fold (30% of control cells) over 96 hours. Our results show that both gap junction and vesicular/exosomal intercellular delivery pathways from hMSCs to target cancer cells deliver oligonucleotides and function to either induce cell death or significantly reduce their proliferation. Thus, hMSC-based cellular delivery is an effective method of delivering synthetic oligonucleotides that can significantly reduce tumor cell growth and should be further investigated as a possible approach to cancer therapy.

Early- and late-occurring damage in bone marrow cells of male CBA/Ca mice exposed whole-body to 1 GeV/n 48Ti ions.

PURPOSE: To determine the early- and late-occurring damage in the bone marrow (BM) and peripheral blood cells of male CBA/Ca mice after exposure to 0, 0.1, 0.25, or 0.5 Gy of 1 GeV/n titanium (48Ti) ions (one type of space radiation). METHOD: We used the mouse in vivo blood-erythrocyte micronucleus (MN) assay for evaluating the cytogenetic effects of various doses of 1 GeV/n 48Ti ions. The MN assay was coupled with the characterization of epigenetic alterations (the levels of global 5-methylcytosine and 5-hydroxymethylcytosine) in DNA samples isolated from BM cells. These analyses were performed in samples collected at an early time-point (1 week) and a late time-point (6 months) post-irradiation. RESULTS: Our results showed that 48Ti ions induced genomic instability in exposed mice. Significant dose-dependent loss of global 5-hydroxymethylcytosine was found but there were no changes in global 5-methylcytosine levels. CONCLUSION: Since persistent genomic instability and loss of global 5-hydroxymethylcytosine are linked to cancer, our findings suggest that exposure to 48Ti ions may pose health risks.

Regulation of HCN2 Current by PI3K/Akt Signaling.

It has long been known that heart rate is regulated by the autonomic nervous system. Recently, we demonstrated that the pacemaker current, I f , is regulated by phosphoinositide 3-kinase (PI3K) signaling independently of the autonomic nervous system. Inhibition of PI3K in sinus node (SN) myocytes shifts the activation of I f by almost 16 mV in the negative direction. I f in the SN is predominantly mediated by two members of the HCN gene family, HCN4 and HCN1. Purkinje fibers also possess I f and are an important secondary pacemaker in the heart. In contrast to the SN, they express HCN2 and HCN4, while ventricular myocytes, which do not normally pace, express HCN2 alone. In the current work, we investigated PI3K regulation of HCN2 expressed in HEK293 cells. Treatment with the PI3K inhibitor PI-103 caused a negative shift in the activation voltage and a dramatic reduction in the magnitude of the HCN2 current. Similar changes were also seen in cells treated with an inhibitor of the protein kinase Akt, a downstream effector of PI3K. The effects of PI-103 were reversed by perfusion of cells with phosphatidylinositol 3,4,5-trisphosphate (the second messenger produced by PI3K) or active Akt protein. We identified serine 861 in mouse HCN2 as a putative Akt phosphorylation site. Mutation of S861 to alanine mimicked the effects of Akt inhibition on voltage dependence and current magnitude. In addition, the Akt inhibitor had no effect on the mutant channel. These results suggest that Akt phosphorylation of mHCN2 S861 accounts for virtually all of the observed actions of PI3K signaling on the HCN2 current. Unexpectedly, Akt inhibition had no effect on I f in SN myocytes. This result raises the possibility that diverse PI3K signaling pathways differentially regulate HCN-induced currents in different tissues, depending on the isoforms expressed.

Inhibition of phosphoenolpyruvate carboxykinase blocks lactate utilization and impairs tumor growth in colorectal cancer.

BACKGROUND: Metabolic reprogramming is a key feature of malignant cells. While glucose is one of the primary substrates for malignant cells, cancer cells also display a remarkable metabolic flexibility. Depending on nutrient availability and requirements, cancer cells will utilize alternative fuel sources to maintain the TCA cycle for bioenergetic and biosynthetic requirements. Lactate was typically viewed as a passive byproduct of cancer cells. However, studies now show that lactate is an important substrate for the TCA cycle in breast, lung, and pancreatic cancer. METHODS: Metabolic analysis of colorectal cancer (CRC) cells was performed using a combination of bioenergetic analysis and 13C stable isotope tracing. RESULTS: We show here that CRC cells use lactate to fuel the TCA cycle and promote growth especially under nutrient-deprived conditions. This was mediated in part by maintaining cellular bioenergetics. Therefore targeting the ability of cancer cells to utilize lactate via the TCA cycle would have a significant therapeutic benefit. Phosphoenolpyruvate carboxykinase (PEPCK) is an important cataplerotic enzyme that promotes TCA cycle activity in CRC cells. Treatment of CRC cells with low micromolar doses of a PEPCK inhibitor (PEPCKi) developed for diabetes decreased cell proliferation and utilization of lactate by the TCA cycle in vitro and in vivo. Mechanistically, we observed that the PEPCKi increased nutrient stress as determined by decreased cellular bioenergetics including decreased respiration, ATP levels, and increased AMPK activation. 13C stable isotope tracing showed that the PEPCKi decreased the incorporation of lactate into the TCA cycle. CONCLUSIONS: These studies highlight lactate as an important substrate for CRC and the use of PEPCKi as a therapeutic approach to target lactate utilization in CRC cells.

Improvement of Ulcerations in Treatment-Resistant Chronic Scarring in a Patient with Pyoderma Gangrenosum After Improving Vascular Insufficiency, Gently Removing Necrotic Debris, and Decreasing Wound Fluid.

BACKGROUND Classical pyoderma gangrenosum is a rare, inflammatory, neutrophilic dermatosis that commonly presents with severe ulcerations on the lower extremities and is often misdiagnosed and mistreated. Delay in treatments can lead to worsening of the ulcerations and allows for multiple comorbid factors. Pyoderma gangrenosum is most commonly treated with immunosuppressants or anti-inflammatory agents and is often worsened by surgical procedures due to the presence of pathergy. In acute cases, a course of anti-inflammatory treatments works well in alleviating symptoms and reducing ulcerations and residual scarring. However, in chronic cases with the presence of severe scarring and necrotic ulcerations, the simple implementation of systemic immunosuppressants is frequently ineffective alone. Although not mentioned in most case reports on pyoderma gangrenosum, the chronicity of its inflammatory component can lead to necrosis and scarring and subsequent vascular insufficiency. CASE REPORT We present a severe case of chronic ulcerative pyoderma gangrenosum in a patient who had treatment-resistant ulcerations and cribriform edematous scarring with subsequent vascular insufficiency of the right lower extremity. This patient, while receiving topical clobetasol, had marked improvement in the healing of his ulcerations only after starting a novel course of cadexomer iodine, compression stockings, and pentoxifylline. CONCLUSIONS The efficacy of non-anti-inflammatory treatments indicates that chronic pyoderma gangrenosum with extensive scarring is commonly associated with the comorbid factors of vascular insufficiency, necrotic debris, and extensive wound fluid. In cases of ulcerations in chronic pyoderma gangrenosum that are resistant to anti-inflammatory treatments alone, one should identify and address other compounding factors that may inhibit wound healing.

Sorption and degradation of neonicotinoid insecticides in tropical soils.

Neonicotinoids are the most widely applied class of insecticides in cocoa farming in Ghana. Despite the intensive application of these insecticides, knowledge of their fate in the Ghanaian and sub-Saharan African environment remains low. This study examined the behavior of neonicotinoids in soils from cocoa plantations in Ghana by estimating their sorption and degradation using established kinetic models and isotherms. Studies of sorption were conducted using the batch equilibrium method on imidacloprid, thiamethoxam, clothianidin, acetamiprid and thiacloprid, while degradation of imidacloprid, thiamethoxam and their respective deuterated counterparts was studied using models proposed by the European forum for coordination of pesticide fate and their use (FOCUS). Analytes were extracted using the quick, easy, cheap, effective, rugged and safe (QuEChERS) procedure and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Average recoveries were high (≥ 85%) for all analytes. The findings from the study suggest that neonicotinoid insecticides may be persistent in the soils studied based on estimated half-lives > 150 days. The study also revealed generally low-sorption coefficients for neonicotinoids in soils, largely influenced by soil organic carbon.

Late Effects of Low-Dose Radiation on the Bone Marrow, Lung, and Testis Collected From the Same Exposed BALB/cJ Mice.

We used 3 biological metrics highly relevant to health risks, that is, cell death, inflammation, and global DNA methylation, to determine the late effects of low doses (0.05 or 0.1 Gy) of 137Cs γ rays on the bone marrow, lung, and testis collected at 6 months post-irradiation from the same exposed BALB/cJ mouse. This integrative approach has not been used for such a purpose. Mice exposed to 0 or 1 Gy of radiation served as a sham or positive control group, respectively. The results could deliver information for better health risk assessment across tissues, including better scientific basis for radiation protection and clinical application. We found no changes in the levels of all studied biological metrics (except a significant increase in the levels of an anti-inflammatory cytokine, ie, interleukin 10) in tissues of 0.05-Gy exposed mice, when compared to those in sham controls. In contrast, significantly increased levels of cell death and inflammation, including a significant loss of global 5-hydroxymethylcytosine, were found in all tissues of the same mice exposed to 0.1 or 1.0 Gy. Our data demonstrated not only no harm but also hormesis in the 0.05-Gy exposed mice. However, the hormetic effect appears to be dependent on biological metrics and tissue.

Induction of Chronic Inflammation and Altered Levels of DNA Hydroxymethylation in Somatic and Germinal Tissues of CBA/CaJ Mice Exposed to (48)Ti Ions.

Although the lung is one of the target organs at risk for cancer induction from exposure to heavy ions found in space, information is insufficient on cellular/molecular responses linked to increased cancer risk. Knowledge of such events may aid in the development of new preventive measures. Furthermore, although it is known that germinal cells are sensitive to X- or γ-rays, there is little information on the effects of heavy ions on germinal cells. Our goal was to investigate in vivo effects of 1 GeV/n (48)Ti ions (one of the important heavy ions found in the space environment) on somatic (lung) and germinal (testis) tissues collected at various times after a whole body irradiation of CBA/CaJ mice (0, 0.1, 0.25, or 0.5 Gy, delivered at 1 cGy/min). We hypothesized that (48)Ti-ion-exposure induced damage in both tissues. Lung tissue was collected from each mouse from each treatment group at 1 week, 1 month, and 6 months postirradiation. For the testis, we collected samples at 6 months postirradiation. Hence, only late-occurring effects of (48)Ti ions in the testis were studied. There were five mice per treatment group at each harvest time. We investigated inflammatory responses after exposure to (48)Ti ions by measuring the levels of activated nuclear factor kappa B and selected pro-inflammatory cytokines in both tissues of the same mouse. These measurements were coupled with the quantitation of the levels of global 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC). Our data clearly showed the induction of chronic inflammation in both tissues of exposed mice. A dose-dependent reduction in global 5hmC was found in the lung at all time-points and in testes collected at 6 months postirradiation. In contrast, significant increases in global 5mC were found only in lung and testes collected at 6 months postirradiation from mice exposed to 0.5 Gy of 1 GeV/n (48)Ti ions. Overall, our data showed that (48)Ti ions may create health risks in both lung and testicular tissues.

Exposure to TiO2 nanoparticles increases Staphylococcus aureus infection of HeLa cells.

BACKGROUND: Titanium dioxide (TiO2) is one of the most common nanoparticles found in industry ranging from food additives to energy generation. Approximately four million tons of TiO2 particles are produced worldwide each year with approximately 3000 tons being produced in nanoparticulate form, hence exposure to these particles is almost certain. RESULTS: Even though TiO2 is also used as an anti-bacterial agent in combination with UV, we have found that, in the absence of UV, exposure of HeLa cells to TiO2 nanoparticles significantly increased their risk of bacterial invasion. HeLa cells cultured with 0.1 mg/ml rutile and anatase TiO2 nanoparticles for 24 h prior to exposure to bacteria had 350 and 250 % respectively more bacteria per cell. The increase was attributed to bacterial polysaccharides absorption on TiO2 NPs, increased extracellular LDH, and changes in the mechanical response of the cell membrane. On the other hand, macrophages exposed to TiO2 particles ingested 40 % fewer bacteria, further increasing the risk of infection. CONCLUSIONS: In combination, these two factors raise serious concerns regarding the impact of exposure to TiO2 nanoparticles on the ability of organisms to resist bacterial infection.

PEPCK Coordinates the Regulation of Central Carbon Metabolism to Promote Cancer Cell Growth.

Phosphoenolpyruvate carboxykinase (PEPCK) is well known for its role in gluconeogenesis. However, PEPCK is also a key regulator of TCA cycle flux. The TCA cycle integrates glucose, amino acid, and lipid metabolism depending on cellular needs. In addition, biosynthetic pathways crucial to tumor growth require the TCA cycle for the processing of glucose and glutamine derived carbons. We show here an unexpected role for PEPCK in promoting cancer cell proliferation in vitro and in vivo by increasing glucose and glutamine utilization toward anabolic metabolism. Unexpectedly, PEPCK also increased the synthesis of ribose from non-carbohydrate sources, such as glutamine, a phenomenon not previously described. Finally, we show that the effects of PEPCK on glucose metabolism and cell proliferation are in part mediated via activation of mTORC1. Taken together, these data demonstrate a role for PEPCK that links metabolic flux and anabolic pathways to cancer cell proliferation.