Evaluation of the Effects of Airborne Particulate Matter on Bone Marrow-Mesenchymal Stem Cells (BM-MSCs): Cellular, Molecular and Systems Biological Approaches

Impacts and mechanisms of PM2.5 on bone

Osteoporosis is a metabolic bone disease, which is characterized by a decreased bone mass and deterioration of bone microstructure, resulting in increased bone fragility and a higher risk of fracture. The main pathological process of osteoporosis is the dynamic imbalance between bone absorption and bone formation, which can be caused by various factors such as air pollution. Particulate matter (PM)2.5 refers to the fine particles in the atmosphere, which are small in volume and large in specific surface area. These particles are prone to carrying toxic substances and have negative effects on several extrapulmonary organs, including bones. In this review, we present relevant data from studies, which show that PM2.5 is associated with abnormal bone turnover and osteoporosis. PM2.5 may cause or aggravate bone loss by stimulating an inflammatory response, inducing oxidative damage, reducing estrogen efficiency by competitive binding to estrogen receptors, or endocrine disorder mediated by binding with aromatic hydrocarbon receptors, and affecting the synthesis of vitamin D to reduce calcium absorption. The cellular and molecular mechanisms involved in these processes are also summarized in this review.

PM2.5 exposure inhibits osteoblast differentiation by increasing the ubiquitination and degradation of Smad4

Increasing epidemiological evidence has shown that PM2.5 exposure is significantly associated with the occurrence of osteoporosis. It has been well demonstrated that PM2.5 exposure enhanced the differentiation and function of osteoclasts by indirectly causing chronic inflammation, while the mechanism in osteoblasts remains unclear. In our study, toxic effects were evaluated by direct exposure of 20-80 μg/ml PM2.5 to MC3T3-E1 cells and BMSCs. The results showed that PM2.5 exposure did not affect cell viability via proliferation and apoptosis, but significantly inhibited osteoblast differentiation in a dose-dependent manner. Osteogenic transcription factors Runx2 and Sp7 and other biomarkers Alp and Ocn decreased after PM2.5 exposure. RNA-seq revealed TGF-β signaling was involved in PM2.5 exposure inhibited osteoblast differentiation, which led to P-Smad1/5 and P-Smad2 reduction in the nucleus by increasing the ubiquitination and degradation of Smad4. At last, the inflammation response increased in MC3T3-E1 cells with PM2.5 exposure. Moreover, the mRNA levels of Mmp9 increased in bone marrow-derived macrophage cells treated with the conditional medium collected from MC3T3-E1 cells exposed to PM2.5. Overall, these results indicated that PM2.5 exposure inhibits osteoblast differentiation and concurrently increases the maturation of osteoclasts. Our study provides in-depth mechanistic insights into the direct impact of PM2.5 exposure on osteoblast, which would indicate the unrecognized role of PM2.5 on osteoporosis.

Effects of fine particulate matter on bone marrow-conserved hematopoietic and mesenchymal stem cells: a systematic review

The harmful effects of fine particulate matter ≤2.5 µm in size (PM2.5) on human health have received considerable attention. However, while the impact of PM2.5 on the respiratory and cardiovascular systems has been well studied, less is known about the effects on stem cells in the bone marrow (BM). With an emphasis on the invasive characteristics of PM2.5, this review examines the current knowledge of the health effects of PM2.5 exposure on BM-residing stem cells. Recent studies have shown that PM2.5 enters the circulation and then travels to distant organs, including the BM, to induce oxidative stress, systemic inflammation and epigenetic changes, resulting in the reduction of BM-residing stem cell survival and function. Understanding the broader health effects of air pollution thus requires an understanding of the invasive characteristics of PM2.5 and its direct influence on stem cells in the BM. As noted in this review, further studies are needed to elucidate the underlying processes by which PM2.5 disturbs the BM microenvironment and inhibits stem cell functionality. Strategies to prevent or ameliorate the negative effects of PM2.5 exposure on BM-residing stem cells and to maintain the regenerative capacity of those cells must also be investigated. By focusing on the complex relationship between PM2.5 and BM-resident stem cells, this review highlights the importance of specific measures directed at safeguarding human health in the face of rising air pollution.

Anemia is associated with long-term exposure to PM2.5 and its components: a large population-based study in Southwest China

Background

Anemia is linked to PM2.5 (particulate matter with aerodynamic diameters of ⩽2.5 μm) exposure, which can increase the risk of various negative health outcomes. It remains unclear which PM2.5 components are associated with anemia and the respective contribution of each component to this association.

Objective

This study aimed at investigating the association between PM2.5 and anemia in the general population and to identify the most critical PM2.5 toxic components in this association.

Design

Cross-sectional study.

Methods

Our study involved a large cohort of 73,511 individuals aged 30-79 from China's multi-ethnic population. We employed satellite observations and the chemical transport model (GEOS-Chem)to estimate the long-term exposure to PM2.5 and its components. Anemia was defined, according to WHO guidelines, as Hb levels below 130 g/L for men and below 120 g/L for women. Through logistic regression, we investigated the association between PM2.5 components and anemia. By utilizing weighted quantile sum (WQS) analysis, we identified key components and gained insights into their combined impact on anemia. Overall, our study sheds light on the relationship between PM2.5 exposure, its constituents, and the risk of anemia in a large cohort.

Results

PM2.5 and three components, nitrate (NIT), organic matter (OM), and soil particles (SOIL), were associated with anemia. Per-standard deviation increase in the 3-year average concentrations of PM2.5 [odds ratio (OR): 1.14, 95% confidence interval (CI): 1.01, 1.28], NIT (1.20, 1.06, 1.35), OM (1.17, 1.04, 1.32), and SOIL (1.22, 1.11, 1.33) were associated with higher odds of anemia. In WQS regression analysis, the WQS index was associated with anemia (OR: 1.29, 95% CI: 1.13, 1.47). SOIL has the highest weight among all PM2.5 components.

Conclusions

Long-term exposure to PM2.5 and its constituents is associated with anemia. Moreover, SOIL might be the most critical component of the relationship between PM2.5 and anemia. Our research increases the evidence of the association between PM2.5 and anemia in the general population, and targeted emission control measures should be taken into consideration to mitigate the adverse effects of PM2.5-related anemia.

Exposure of newborns to atmospherically relevant artificial particulate matter induces hematopoietic stem cell senescence

Research on the negative impacts of PM_2.5 have been focused on lung, brain, immune, and metabolism-related diseases. However, little is known about the mechanism underlying the effects of PM_2.5 on the modulation of hematopoietic stem cell (HSC) fate. Maturation of the hematopoietic system and differentiation of hematopoietic stem progenitor cells (HSPCs) occurs soon after birth when infants are susceptible to external stresses. We investigated how exposure to atmospherically relevant artificial particulate matter of diameter < 2.5 µm (termed, PM_2.5) affects HSPCs in newborns. The lungs of newborn mice exposed to PM_2.5 exhibited higher levels of oxidative stress and inflammasome activation, which continued during aging. PM_2.5 also stimulated oxidative stress and inflammasome activation in bone marrow (BM). PM_2.5-exposed infant mice at 12 months but not at 6 months displayed progressive senescence of HSCs accompanied by preferential impairment of the BM microenvironment with age-related phenotypes, as evidenced by colony-forming assay and serial transplantation and animal survival experiments. Further, PM_2.5-exposed middle-aged mice did not exhibit radioprotective potential. Collectively, exposure of newborns to PM_2.5 causes progressive senescence of HSCs. These findings revealed a novel mechanism by which PM_2.5 affects the fate of HSCs, highlighting the crucial role of early life exposure to air pollution in determining human health outcomes.

The Prognostic Value of the Developmental Gene FZD6 in Young Saudi Breast Cancer Patients: A Biomarkers Discovery and Cancer Inducers OncoScreen Approach

Wnt signalling receptors, Frizzleds (FZDs), play a pivotal role in many cellular events during embryonic development and cancer. Female breast cancer (BC) is currently the worldwide leading incident cancer type that cause 1 in 6 cancer-related death. FZD receptors expression in cancer was shown to be associated with tumour development and patient outcomes including recurrence and survival. FZD6 received little attention for its role in BC and hence we analysed its expression pattern in a Saudi BC cohort to assess its prognostic potential and unravel the impacted signalling pathway. Paraffin blocks from approximately 405 randomly selected BC patients aged between 25 and 70 years old were processed for tissue microarray using an automated tissue arrayer and then subjected to FZD6 immunohistochemistry staining using the Ventana platform. Besides, Ingenuity Pathway Analysis (IPA) knowledgebase was used to decipher the upstream and downstream regulators of FZD6 in BC. TargetScan and miRabel target-prediction databases were used to identify the potential microRNA to regulate FZD6 expression in BC. Results showed that 60% of the BC samples had a low expression pattern while 40% showed a higher expression level. FZD6 expression analysis showed a significant correlation with tumour invasion (p < 0.05), and borderline significance with tumour grade (p = 0.07). FZD6 expression showed a highly significant association with the BC patients’ survival outcomes. This was mainly due to the overall patients’ cohort where tumours with FZD6 elevated expression showed higher recurrence rates (DFS, p < 0.0001, log-rank) and shorter survival times (DSS, p < 0.02, log-rank). Interestingly, the FZD6 prognostic value was more potent in younger BC patients as compared to those with late onset of the disease. TargetScan microRNA target-prediction analysis and validated by miRabel showed that FZD6 is a potential target for a considerable number of microRNAs expressed in BC. The current study demonstrates a potential prognostic role of FZD6 expression in young BC female patients and provides a better understanding of the involved molecular silencing machinery of the Wnt/FZD6 signalling. Our results should provide a better understanding of FZD6 role in BC by adding more knowledge that should help in BC prevention and theranostics.

Diesel Exhaust Particles Impair Therapeutic Effect of Human Wharton's Jelly-Derived Mesenchymal Stem Cells against Experimental Colitis through ROS/ERK/cFos Signaling Pathway

Background and Objectives

Epidemiological investigations have shown positive correlations between increased diesel exhaust particles (DEP) in ambient air and adverse health outcomes. DEP are the major constituent of particulate atmospheric pollution and have been shown to induce proinflammatory responses both in the lung and systemically. Here, we report the effects of DEP exposure on the properties of human Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs), including stemness, regeneration, and immunomodulation.

Methods and Results

Non-apoptotic concentrations of DEP (10 μg/ml) inhibited the migration and osteogenic differentiation capacity of WJ-MSCs. Gene expression profiling showed that DEP increased intracellular reactive oxygen species (ROS) and expression of pro-inflammatory and metabolic-process-related genes including cFos. Furthermore, WJ-MSCs cultured with DEP showed impaired suppression of T cell proliferation that was reversed by inhibition of ROS or knockdown of cFos. ERK inhibition assay revealed that DEP-induced ROS regulated cFos through activation of ERK but not NF-κB signaling. Overall, low concentrations of DEP (10 μg/ml) significantly suppressed the stemness and immunomodulatory properties of WJ-MSCs through ROS/ERK/cFos signaling pathways. Furthermore, WJ-MSCs cultured with DEP impaired the therapeutic effect of WJ-MSCs in experimental colitis mice, but was partly reversed by inhibition of ROS.

Conclusions

Taken together, these results indicate that exposure to DEP enhances the expression of pro-inflammatory cytokines and immune responses through a mechanism involving the ROS/ERK/cFos pathway in WJ-MSCs, and that DEP-induced ROS damage impairs the therapeutic effect of WJ-MSCs in colitis. Our results suggest that modulation of ROS/ERK/cFos signaling pathways in WJ-MSCs might be a novel therapeutic strategy for DEP-induced diseases.

Particulate Matter 2.5 and Hematological Disorders From Dust to Diseases: A Systematic Review of Available Evidence

Particulate matter 2.5 (PM_2.5) in the air enters the human body by diffusion into the blood. Therefore, hematological abnormalities might occur because of these toxic particles, but few studies on this issue have been reported. According to Cochrane guidance, we performed a systematic review on the relationship between exposure to PM_2.5 and the risk of hematological disorders. Ten articles were included in this review. Anemia was found among children and elderly populations with 2- to 5-year PM_2.5 exposure. Young children from mothers exposed to air pollution during pregnancy had a higher incidence of leukemia similar to the elderly. Supporting these data, outdoor workers also showed abnormal epigenetic modifications after exposure to very high PM_2.5 levels. Adults living in high PM_2.5 areas for 2 years were more likely to develop thrombocytosis. Finally, elderly populations with 7- to 8-year PM_2.5 exposure showed increased risks of venous thromboembolism. In conclusion, the associations between PM_2.5 and hematological aberrations among high-risk people with long-term exposure were reported.

Unraveling the Catha edulis Extract Effects on the Cellular and Molecular Signaling in SKOV3 Cells

Khat (Catha edulis (Vahl) Endl.) is an evergreen flowering shrub used as a stimulant in many regions worldwide including East Africa, the Arabian Peninsula, Europe, and the United States. Chewing leaves of khat induces excitement and euphoria, which are primarily attributed to two major constituents, cathinone and cathine. Khat also contains other important constituents such as cathedulins. A considerable number of studies reported side effects induced by the khat extracts to both embryos and adults. These include teratogenicity and developmental retardation, oral cancer and ulcers, high blood pressure, and myocardial infarction. So far, little attention has been paid to the effects of khat extracts on the molecular signaling interactions. We aimed in this study to investigate this through evaluating the effects of khat extracts on SKOV3, a human ovarian adenocarcinoma cell line. We show, by in vitro assays, that khat induces several cellular defects including reduced cell size, cell membrane damage, and apoptosis. At high khat extract concentrations, the cell metabolic activity, cell cycle, and cellular proliferation were affected. RT-qPCR analysis showed an increase in the gene expression of the apoptotic marker BAX, the tumor suppressor p53, and the inflammatory cytokine IL-6. Protein expression analysis by immunostaining showed downregulation of β-catenin, E-cadherin, and Ki-67 and upregulation of FZD8 and SPRY2, suggesting that Wnt and FGF signaling were implicated. SwissTargetPrediction in silico analysis showed that khat constituents cathine, cathinone, catheduline K2, and catheduline E5 bind to family A G-protein-coupled receptor, cause many neurological diseases and disorders such as Alzheimer's, schizophrenia, depression, and anxiety, and induce many ovarian cancer-related diseases. The analysis also showed that important signaling pathways such as CREB, Wnt, FGF, IL-6, and ERK/MAPK, and that of the endometrial cancer, and cell cycle were implicated. Upstream regulators of cathine and cathinone were found to potentially target several molecules including interleukin-8, MMP2, PLAU, and micro-RNAs. In conclusion, khat induces significant cellular and molecular changes that could potentially cause a wide range of serious diseases and syndromes. Such an impact could have a heavy burden on the health care system in the countries where khat is consumed.

Differential Sex-Dependent Regulation of the Alveolar Macrophage miRNome of SP-A2 and co-ex (SP-A1/SP-A2) and Sex Differences Attenuation after 18 h of Ozone Exposure

Background: Human SP-A1 and SP-A2, encoded by SFTPA1 and SFTPA2, and their genetic variants differentially impact alveolar macrophage (AM) functions and regulation, including the miRNome. We investigated whether miRNome differences previously observed between AM from SP-A2 and SP-A1/SP-A2 mice are due to continued qualitative differences or a delayed response of mice carrying a single gene. Methods: Human transgenic (hTG) mice, carrying SP-A2 or both SP-A genes, and SP-A-KO mice were exposed to filtered air (FA) or ozone (O₃)_. AM miRNA levels, target gene expression, and pathways determined 18 h after O₃ exposure. RESULTS: We found (a) differences in miRNome due to sex, SP-A genotype, and exposure; (b) miRNome of both sexes was largely downregulated by O₃, and co-ex had fewer changed (≥2-fold) miRNAs than either group; (c) the number and direction of the expression of genes with significant changes in males and females in co-ex are almost the opposite of those in SP-A2; (d) the same pathways were found in the studied groups; and (e) O₃ exposure attenuated sex differences with a higher number of genotype-dependent and genotype-independent miRNAs common in both sexes after O₃ exposure. Conclusion: Qualitative differences between SP-A2 and co-ex persist 18 h post-O₃, and O₃ attenuates sex differences.

Combined exposure to formaldehyde and PM2.5: Hematopoietic toxicity and molecular mechanism in mice

PM2.5 and formaldehyde (FA) are major outdoor and indoor air pollutants in China, respectively, and both are known to be harmful to human health and to be carcinogenic. Of all the known chronic health effects, leukaemia is one of the most serious health risks associated with these two pollutants. To explore the influence and underlying mechanisms of exposure to formaldehyde and PM2.5 on hematopoietic toxicity, we systematically studied the toxicity induced in hematopoietic organs: bone marrow (BM); spleen; and myeloid progenitor cells (MPCs). Male Balb/c mice were exposed to: PM2.5 (20, 160 μg/kg·d) at a dose of 40 μL per mouse or formaldehyde (0.5, 3.0 mg/m3) for 8 h per day for 2 weeks or co-exposed to formaldehyde and PM2.5 (20 μg/kg·d PM2.5 + 0.5 mg/m3 FA, 20 μg/kg·d PM2.5 + 3 mg/m3 FA, 160 μg/kg·d PM2.5 + 0.5 mg/m3 FA, 160 μg/kg·d PM2.5 + 3 mg/m3 FA) for 2 weeks. Similar toxic effects were found in the formaldehyde-only and PM2.5-only groups, including significant decrease of blood cells and MPCs, along with decreased expression of hematopoietic growth factors. In addition, individual exposure of formaldehyde or PM2.5 increased oxidative stress, DNA damage and immune system disorder by destroying the balance of Th1/Th2, and Treg/Th17. DNA repair was markedly inhibited by deregulating the mammalian target of rapamycin (mTOR) pathway. Combined exposure to PM2.5 and formaldehyde led to more severe effects. Administration of Vitamin E (VE) was shown to attenuate these effects. In conclusion, our findings suggested that PM2.5 and formaldehyde may induce hematopoietic toxicity by reducing the expression of hematopoietic growth factors, increasing oxidative stress and DNA damage, activating the 'immune imbalance' pathway and suppressing the DNA-repair related mTOR pathway. The hematopoietic toxicity induced by combined exposure of PM2.5 and formaldehyde might provide further insights into the increased incidence of hematological diseases, including human myeloid leukaemia.

Cellular and Molecular Mechanisms of Environmental Pollutants on Hematopoiesis

Hematopoiesis is a complex and intricate process that aims to replenish blood components in a constant fashion. It is orchestrated mostly by hematopoietic progenitor cells (hematopoietic stem cells (HSCs)) that are capable of self-renewal and differentiation. These cells can originate other cell subtypes that are responsible for maintaining vital functions, mediate innate and adaptive immune responses, provide tissues with oxygen, and control coagulation. Hematopoiesis in adults takes place in the bone marrow, which is endowed with an extensive vasculature conferring an intense flow of cells. A myriad of cell subtypes can be found in the bone marrow at different levels of activation, being also under constant action of an extensive amount of diverse chemical mediators and enzymatic systems. Bone marrow platelets, mature erythrocytes and leukocytes are delivered into the bloodstream readily available to meet body demands. Leukocytes circulate and reach different tissues, returning or not returning to the bloodstream. Senescent leukocytes, specially granulocytes, return to the bone marrow to be phagocytized by macrophages, restarting granulopoiesis. The constant high production and delivery of cells into the bloodstream, alongside the fact that blood cells can also circulate between tissues, makes the hematopoietic system a prime target for toxic agents to act upon, making the understanding of the bone marrow microenvironment vital for both toxicological sciences and risk assessment. Environmental and occupational pollutants, therapeutic molecules, drugs of abuse, and even nutritional status can directly affect progenitor cells at their differentiation and maturation stages, altering behavior and function of blood compounds and resulting in impaired immune responses, anemias, leukemias, and blood coagulation disturbances. This review aims to describe the most recently investigated molecular and cellular toxicity mechanisms of current major environmental pollutants on hematopoiesis in the bone marrow.

PM2.5 collecting in a tire manufacturing plant affects epithelial differentiation of human umbilical cord derived mesenchymal stem cells by Wnt/β-catenin pathway

Mesenchymal stem cells (MSCs) can differentiate into pulmonary epithelial cells by Wnt/β-catenin pathway and promote lung repair. However, whether fine particulate matter (PM_2.5) could affect Wnt pathway and finally reduce the ability of MSCs to differentiate into epithelial cells is still unknown. This study aimed to investigate whether PM_2.5 could inhibit the epithelial differentiation of human umbilical cord-derived MSCs cells (hUCMSCs) and the related underlying mechanism. hUCMSCs were incubated with different concentrations of PM_2.5. Then, the cell viability, reactive oxygen species level, and single-cell sphere formation were assessed. The underlying mechanism of PM_2.5 in epithelial differentiation of hUCMSCs was further evaluated by co-culturing hUCMSCs with A549 cells. Our results demonstrated that PM_2.5 exposures could affect the expressions of β-catenin and lung epithelial markers (zonula occludens-1 (ZO-1); cytokeratins 5 and 19) in the co-cultured hUCMSCs. The Wnt/β-catenin pathway is involved in regulating the epithelial differentiation of MSCs. As expected, co-treatment with Wnt3a, which is the activator of the Wnt pathway, attenuated the downregulation of lung epithelial markers (ZO-1; cytokeratins 5 and 19) and paracrine factors (keratinocyte growth factor and hepatocyte growth factor) caused by PM_2.5. Altogether, these results demonstrated that PM_2.5 could affect the epithelial differentiation of hUCMSCs via the Wnt/β-catenin pathway.

Carnosine Supplementation Mitigates the Deleterious Effects of Particulate Matter Exposure in Mice

Background Exposure to fine airborne particulate matter ( PM 2.5) induces quantitative and qualitative defects in bone marrow-derived endothelial progenitor cells of mice, and similar outcomes in humans may contribute to vascular dysfunction and the cardiovascular morbidity and mortality associated with PM 2.5 exposure. Nevertheless, mechanisms underlying the pervasive effects of PM 2.5 are unclear and effective interventional strategies to mitigate against PM 2.5 toxicity are lacking. Furthermore, whether PM 2.5 exposure affects other types of bone marrow stem cells leading to additional hematological or immunological dysfunction is not clear. Methods and Results Mice given normal drinking water or that supplemented with carnosine, a naturally occurring, nucleophilic di-peptide that binds reactive aldehydes, were exposed to filtered air or concentrated ambient particles. Mice drinking normal water and exposed to concentrated ambient particles demonstrated a depletion of bone marrow hematopoietic stem cells but no change in mesenchymal stem cells. However, HSC depletion was significantly attenuated when the mice were placed on drinking water containing carnosine. Carnosine supplementation also increased the levels of carnosine-propanal conjugates in the urine of CAPs-exposed mice and prevented the concentrated ambient particles-induced dysfunction of endothelial progenitor cells as assessed by in vitro and in vivo assays. Conclusions These results suggest that exposure to PM 2.5 has pervasive effects on different bone marrow stem cell populations and that PM 2.5-induced hematopoietic stem cells depletion, endothelial progenitor cell dysfunction, and defects in vascular repair can be mitigated by excess carnosine. Carnosine supplementation may be a viable approach for preventing PM 2.5-induced immune dysfunction and cardiovascular injury in humans.

Aryl hydrocarbon receptor mediates the cardiac developmental toxicity of EOM from PM2.5 in P19 embryonic carcinoma cells

Ambient fine particulate matter (PM_2.5) has been found to be associated with congenital heart defects, but the molecular mechanisms remain to be elucidated. Our previous study revealed that extractable organic matter (EOM) from PM_2.5 exerted cardiac developmental toxicity in zebrafish embryos. The aim of the current study is to explore the effects of EOM on cardiac differentiation of P19 mouse embryonic carcinoma stem cells. We found that EOM at 10 μg/ml (a non-cytotoxic dose level) significantly reduced the proportion of cardiac muscle troponin (cTnT) positive cells and the percentage of spontaneously beating embryoid bodies, indicating a severe inhibition of cardiac differentiation. Immunofluorescence and qPCR data demonstrated that EOM increased the expression levels of the aryl hydrocarbon receptor (AhR) and its target gene Cyp1A1 and diminished the expression level of β-catenin. Furthermore, EOM treatment significantly upregulated cell proliferation rate and elevated the percentage of γH2A.X positive cells without affecting apoptosis. It is worth noting that the EOM-induced changes in gene expression, cellular proliferation and DNA double strain breaks were attenuated by the AhR antagonist CH223191. In conclusion, our data indicate that AhR mediates the inhibitory effects of EOM (from PM_2.5) on the cardiac differentiation of P19 cells.

Human Wharton's Jelly Stem Cell (hWJSC) Extracts Inhibit Ovarian Cancer Cell Lines OVCAR3 and SKOV3 in vitro by Inducing Cell Cycle Arrest and Apoptosis

Ovarian cancer is a highly lethal and the second highest in mortality among gynecological cancers. Stem cells either naïve or engineered are reported to inhibit various human cancers in both in-vitro and in-vivo. Herein we report the cancer inhibitory properties of human Wharton's jelly stem cell (hWJSC) extracts, namely its conditioned medium (hWJSC-CM) and cell lysate (hWJSC-CL) against two ovarian cancer cell lines (OVCAR3 and SKOV3) in-vitro. Cell metabolic activity assay of OVCAR3 and SKOV3 cells treated with hWJSC-CM (12.5, 25, 50, 75, 100%) and hWJSC-CL (5, 10, 15, 30, and 50 μg/ml) demonstrated concentration dependent inhibition at 24-72 h. Morphological analysis of OVCAR3 and SKOV3 cells treated with hWJSC-CM (50, 75, 100%) and hWJSC-CL (15, 30, and 50 μg/ml) for 24-72 h showed cell shrinkage, membrane damage/blebbings and cell death. Cell cycle assay demonstrated an increase in the sub-G1 and G2M phases of cell cycle following treatment with hWJSC-CM (50, 75, 100%) and hWJSC-CL (10, 15, and 30 μg/ml) at 48 h. Both OVCAR3 and SKOV3 cells demonstrated mild positive expression of activated caspase 3 following treatment with hWJSC-CM (50%) and hWJSC-CL (15 μg/ml) for 24 h. Cell migration of OVCAR3 and SKOV3 cells were inhibited following treatment with hWJSC-CM (50%) and hWJSC-CL (15 μg/ml) for 48 h. Tumor spheres (TS) of OVCAR3 and SKOV3 treated with hWJSC-CM (50, 75, 100%) and hWJSC-CL (10, 15, 30 μg/ml) for 48 h showed altered surface changes including vacuolations and reduction in size of TS. TS of OVCAR3 and SKOV3 also showed the presence of few ovarian cancer stem cells (CSCs) in minimal numbers following treatment with hWJSC-CM (50%) or hWJSC-CL (15 μg/ml) for 48 h. Real-time gene expression analysis of OVCAR3 and SKOV3 treated with hWJSC-CM (50%) or hWJSC-CL (15 μg/ml) for 48 h demonstrated decreased expression of cell cycle regulatory genes (cyclin A2, Cyclin E1), prostaglandin receptor signaling genes (EP2, EP4) and the pro-inflmmatory genes (IL-6, TNF-α) compared to untreated controls. The results indicate that hWJSC-CM and hWJSC-CL inhibit ovarian cancer cells at mild to moderate levels by inducing cellular changes, cell cycle arrest, apoptosis, decreasing the expression of CSC markers and related genes regulation. Therefore, the stem cell factors in hWJSCs extracts can be useful in cancer management.

Seasonal variations in fine particle composition from Beijing prompt oxidative stress response in mouse lung and liver

Exposure to air pollution can induce oxidative stress, inflammation and adverse health effects. To understand how seasonal and chemical variations drive health impacts, we investigated indications for oxidative stress and inflammation in mice exposed to water and organic extracts from urban fine particles/PM_2.5 (particles with aerodynamic diameter ≤ 2.5 μm) collected in Beijing, China. Higher levels of pollution components were detected in heating season (HS, winter and part of spring) PM_2.5 than in the non-heating season (NHS, summer and part of spring and autumn) PM_2.5. HS samples were high in metals for the water extraction and high in polycyclic aromatic hydrocarbons (PAHs) for the organic extraction compared to their controls. An increased inflammatory response was detected in the lung and liver following exposure to the organic extracts compared to the water extracts, and mostly in the HS PM_2.5. While reduced antioxidant response was observed in the lung, it was activated in the liver, again, more in the HS extracts. Nrf2 transcription factor, a master regulator of stress response that controls the basal oxidative capacity and induces the expression of antioxidant response, and its related genes were induced. In the liver, elevated levels of lipid peroxidation adducts were measured, correlated with histologic analysis that revealed morphologic features of cell damage and proliferation, indicating oxidative and toxic damage. In addition, expression of genes related to detoxification of PAHs was observed. Altogether, the study suggests that the acute effects of PM_2.5 can vary seasonally with stronger health effects in the HS than in the NHS in Beijing, China and that some secondary organs may be susceptible for the exposure damage. Specifically, the liver is a potential organ influenced by exposure to organic components such as PAHs from coal or biomass burning and heating.