Multicomponent Pathogen-Mimicking Nanoparticles Induce Intestinal Immune Responses against Paratuberculosis.

Given the worldwide problem posed by enteric pathogens, the discovery of safe and efficient intestinal adjuvants combined with novel antigen delivery techniques is essential to the design of mucosal vaccines. In this work, we designed poly (lactic-co-glycolic acid) (PLGA)-based nanoparticles (NPs) to codeliver all-trans retinoic acid (atRA), novel antigens, and CpG. To address the insolubility of the intestinal adjuvant atRA, we utilized PLGA to encapsulate atRA and form a "nanocapsid" with polydopamine. By leveraging polydopamine, we adsorbed the water-soluble antigens and the TLR9 agonist CpG onto the NPs' surface, resulting in the pathogen-mimicking PLPCa NPs. In this study, the novel fusion protein (HBf), consisting of the Mycobacterium avium subspecies paratuberculosis antigens HBHA, Ag85B, and Bfra, was coloaded onto the NPs. In vitro, PLPCa NPs were shown to promote the activation and maturation of bone marrow-derived dendritic cells. Additionally, we found that PLPCa NPs created an immune-rich microenvironment at the injection site following intramuscular administration. From the results, the PLPCa NPs induced strong IgA levels in the gut in addition to enhancing powerful systemic immune responses. Consequently, significant declines in the bacterial burden and inflammatory score were noted in PLPCa NPs-treated mice. In summary, PLPCa can serve as a novel and safe vaccine delivery platform against gut pathogens, such as paratuberculosis, capable of activating both systemic and intestinal immunity.

Layer-by-layer nanoparticle encapsulating all-trans retinoic acid and CpG as a mucosal adjuvant targeting colorectal cancer.

Colorectal cancer (CRC) ranks among the most prevalent cancers globally, demanding innovative therapeutic strategies. Immunotherapy, a promising avenue, employs cancer vaccines to activate the immune system against tumors. However, conventional approaches fall short of eliciting robust responses within the gastrointestinal (GI) tract, where CRC originates. Harnessing the potential of all-trans retinoic acid (ATRA) and cytosine-phosphorothioate-guanine (CpG), we developed layered nanoparticles using a layer-by-layer assembly method to co-deliver these agents. ATRA, crucial for gut immunity, was efficiently encapsulated alongside CpG within these nanoparticles. Administering these ATRA@CpG-NPs, combined with ovalbumin peptide (OVA), effectively inhibited orthotopic CRC growth in mice. Our approach leveraged the inherent benefits of ATRA and CpG, demonstrating superior efficacy in activating dendritic cells, imprinting T cells with gut-homing receptors, and inhibiting tumor growth. This mucosal adjuvant presents a promising strategy for CRC immunotherapy, showcasing the potential for targeting gut-associated immune responses in combating colorectal malignancies.

Effect of a retinoic acid analogue on BMP-driven pluripotent stem cell chondrogenesis.

Osteoarthritis is the most common degenerative joint condition, leading to articular cartilage (AC) degradation, chronic pain and immobility. The lack of appropriate therapies that provide tissue restoration combined with the limited lifespan of joint-replacement implants indicate the need for alternative AC regeneration strategies. Differentiation of human pluripotent stem cells (hPSCs) into AC progenitors may provide a long-term regenerative solution but is still limited due to the continued reliance upon growth factors to recapitulate developmental signalling processes. Recently, TTNPB, a small molecule activator of retinoic acid receptors (RARs), has been shown to be sufficient to guide mesodermal specification and early chondrogenesis of hPSCs. Here, we modified our previous differentiation protocol, by supplementing cells with TTNPB and administering BMP2 at specific times to enhance early development (referred to as the RAPID-E protocol). Transcriptomic analyses indicated that activation of RAR signalling significantly upregulated genes related to limb and embryonic skeletal development in the early stages of the protocol and upregulated genes related to AC development in later stages. Chondroprogenitors obtained from RAPID-E could generate cartilaginous pellets that expressed AC-related matrix proteins such as Lubricin, Aggrecan, and Collagen II, but additionally expressed Collagen X, indicative of hypertrophy. This protocol could lay the foundations for cell therapy strategies for osteoarthritis and improve the understanding of AC development in humans.

Repeated immunization with ATRA-containing liposomal adjuvant transdifferentiates Th17 cells to a Tr1-like phenotype.

In many autoimmune diseases, autoantigen-specific Th17 cells play a pivotal role in disease pathogenesis. Th17 cells can transdifferentiate into other T cell subsets in inflammatory conditions, however, there have been no attempts to target Th17 cell plasticity using vaccines. We investigated if autoantigen-specific Th17 cells could be specifically targeted using a therapeutic vaccine approach, where antigen was formulated in all-trans retinoic acid (ATRA)-containing liposomes, permitting co-delivery of antigen and ATRA to the same target cell. Whilst ATRA was previously found to broadly reduce Th17 responses, we found that antigen formulated in ATRA-containing cationic liposomes only inhibited Th17 cells in an antigen-specific manner and not when combined with an irrelevant antigen. Furthermore, this approach shifted existing Th17 cells away from IL-17A expression and transcriptomic analysis of sorted Th17 lineage cells from IL-17 fate reporter mice revealed a shift of antigen-specific Th17 cells to exTh17 cells, expressing functional markers associated with T cell regulation and tolerance. In the experimental autoimmune encephalomyelitis (EAE) mouse model of MS, vaccination with myelin-specific (MOG) antigen in ATRA-containing liposomes reduced Th17 responses and alleviated disease. This highlights the potential of therapeutic vaccination for changing the phenotype of existing Th17 cells in the context of immune mediated diseases.

All-trans retinoic acid alleviates collagen-induced arthritis and promotes intestinal homeostasis.

All-trans retinoic acid (ATRA) has emerged as a promising adjunctive treatment for rheumatoid arthritis. However, the mechanism by which ATRA mitigates arthritis remains unclear. In this study, we aimed to explore ATRA alleviation of arthritis and the role of ATRA in regulating intestinal homeostasis. Thus, we established a collagen-induced arthritis (CIA) model in Wistar rats. After 6 weeks of ATRA treatment, the arthritis index of CIA rats decreased, synovial inflammation was alleviated, and the disruption of Th17/Treg differentiation in peripheral blood was reversed. Additionally, the Th17/Treg ratio in the mesenteric lymph nodes decreased and the expression of Foxp3 mRNA increased and that of IL-17 mRNA decreased in the colon and ileum. Microscopically, we observed reduced intestinal inflammation. Transmission electron microscopy revealed that ATRA could repair tight junctions, which was accompanied by an increase in the expression of Claudin-1, Occludin and ZO-1. Moreover, ATRA regulated the composition of the gut microbiota, as was characterized based on the reduced abundance of Desulfobacterota and the increased abundance of Lactobacillus. In conclusion, ATRA demonstrates the potential to alleviate arthritis in CIA rats, which might be correlated with modulating the gut microbiota and regulating the intestinal immune response. Our findings provide novel insights into ATRA-mediated alleviation of arthritis.

Acute kidney injury in acute promyelocytic leukemia: a possible adverse effect of high dose arsenic trioxide in obese patients.

Arsenic trioxide (ATO)-based regimens are standard in acute promyelocytic leukemia (APL). ATO-related nephrotoxicity has not been reported. We reviewed APL patients treated with ATO to identify cases of acute kidney injury (AKI). Clinically significant cases were characterized. Multivariate analysis was performed to identify predictors of idiopathic, clinically significant AKI. One hundred and eight patients were included. ATO dose was 0.15 mg/kg/day using actual body weight with no dose cap. Thirty-one (28.7%) AKI cases were identified, 10 (32.3%) clinically significant. Six were idiopathic; five required dialysis. The proportion with significant, idiopathic AKI was 15.8% in patients receiving >15mg ATO versus 0% in those receiving ≤15mg (p = 0.001). On multivariate analysis, only ATO dose was a significant predictor of clinically significant AKI (odds ratio of 1.91, 95%CI, 1.19-3.07, p = 0.007). High-dose ATO may be associated with significant nephrotoxicity. We recommend that ATO dose be capped at 15 mg to minimize toxicity for this curable disease.

Long-term outcome of children with acute promyelocytic leukemia: a randomized study of oral versus intravenous arsenic by SCCLG-APL group.

Realgar-Indigo naturalis formula (RIF), an oral traditional Chinese medicine mainly containing Realgar (As4S4), is highly effective in treating adult acute promyelocytic leukemia (APL). However, the treatment efficacy and safety of RIF have not been verified in pediatric patients. SCCLG-APL group conducted a multicenter randomized non-inferiority trial to determine whether intravenous arsenic trioxide (ATO) can be substituted by oral RIF in treating pediatric APL. Of 176 eligible patients enrolled, 91 and 85 were randomized to ATO and RIF groups, respectively. Patients were treated with the risk-adapted protocol. Induction, consolidation, and 96-week maintenance treatment contained all-trans-retinoic acid and low-intensity chemotherapy, and either ATO or RIF. The primary endpoint was 5-year event-free survival (EFS). The secondary endpoints were adverse events and hospital days. After a median 6-year follow-up, the 5-year EFS was 97.6% in both groups. However, the RIF group had significantly shorter hospital stays and lower incidence of infection and tended to have less cardiac toxicity. All 4 relapses occurred within 1.5 years after completion of maintenance therapy. No long-term arsenic retentions were observed in either group. Substituting oral RIF for ATO maintains treatment efficacy while reducing hospitalization and adverse events in treating pediatric APL patients, which may be a future treatment strategy for APL.

[Change of the retinoic acid pathway in hypothalamus and pituitary damage induced by combined exposure to low-level Pb~(2+) and 1-nitropyrene in mice].

OBJECTIVE: To observe the expression of the retinoic acid(RA) pathway in hypothalamus and pituitary damage induced by combined exposure of low-level lead and 1-nitropyrene in mice, and to explore the relationship between the changes of RA pathway and hypothalamus and pituitary damage. METHODS: A total of 84 4-week-old ICR mice were randomly divided into the control group, Pb~(2+) tainted group(0.008 mg/L), 1-NP tainted group(0.1 mg/kg), low(0.008 mg/L Pb~(2+)+0.004 mg/kg 1-NP), medium(0.008 mg/L Pb~(2+)+0.02 mg/kg 1-NP), and high-dose co-toxicity group(0.008 mg/L Pb~(2+)+0.1 mg/kg 1-NP) according to body weight, with 14 mice in each group. Among them, Pb~(2+) was provided by lead acetate, added to deionized water and ingested by mice drinking freely, 1-NP was given by intraperitoneal injection, 1-NP was administered by intraperitoneal injection. Record daily water intake and food intake. After 21 consecutive days of exposure, body mass was measured, histological changes in the hypothalamus and pituitary were observed under an optical microscope, and lead content in brain tissue was measured by atomic absorption spectrometry. The real-time fluorescence quantitative PCR was used to detect the abundance of retinoic acid pathway members and c-Jun N-terminal kinases genes(Jnks), and the western blot method was used to detect expression levels of acetaldehyde dehydrogenase 2(ALDH2), cytochrome P450 family member 26A1(CYP26a1) proteins. RESULTS: There was no difference in the mean weekly water intake and food intake of the mice in each group. The body weight of the high-dose co-toxicity group mice((27.4±1.9)g) was lower than that of the control group((29.8±2.3)g)(P<0.05). The level of serum follicle-stimulating hormone(FSH) in the middle and high dose co-toxicity groups((265.01±2.99), (260.42±3.61)pg/mL, respectively) was lower than that in the control group((279.00±1.30)pg/mL, P<0.05). The content of Pb~(2+) in the brain of each group containing Pb~(2+) was higher than that of the control group. In the hypothalamic and pituitary tissues, the abundance of Adh1, Adh2, Rar and Rxr, and ALDH2 levels in the medium and high dose co-toxicity groups were higher than those in the control group(P<0.05). Cyp26a1 gene abundance and protein levels were lower in the medium and high dose co-toxicity groups than in the control group(P<0.05). The abundance of Jnks in the high-dose co-toxicity group was higher than that in the control group(P<0.05). CONCLUSION: Continuous exposure to 0.008 mg/L Pb~(2+)+0.1 mg/kg 1-NP for 21 days can cause damage to the hypothalamus and pituitary of mice, and activate the RA signaling pathway.

In ovo administration of retinoic acid enhances cell-mediated immune responses against an inactivated H9N2 avian influenza virus vaccine.

The H9N2 subtype avian influenza virus (AIV) is a low pathogenic AIV that infects avian species and lead to huge economical losses in the poultry industry. The unique immunomodulatory properties of Retinoic acid (RA), an active component of vitamin A, highlights its potential to enhance chicken's resistance to infectious diseases and perhaps vaccine-induced immunity. Therefore, the present study evaluated the effects of in ovo supplementation of RA on the immunogenicity and protective efficacy of an inactivated avian influenza virus vaccine. On embryonic day 18, eggs were inoculated with either 90 µmol RA/200 µL/egg or diluent into the amniotic sac. On days 7 and 21 post-hatch, birds were vaccinated with 15 µg of ß-propiolactone (BPL) inactivated H9N2 virus via the intramuscular route. One group received BPL in combination with an adjuvant, while the other group received saline solution and served as a non-vaccinated control group. Serum samples were collected on days 7, 14, 21, 28, 35, and 42 post-primary vaccination (ppv) for antibody analysis. On day 24 ppv, spleens were collected, and splenocytes were isolated to analyze cytokine expression, interferon gamma (IFN-γ) production, and cell population. On day 28 ppv, birds in all groups were infected with H9N2 virus and oral and cloacal swabs were collected for TCID50 (50 % Tissue Culture Infectious Dose) assay up to day 7 post-infection. The results demonstrated that in ovo administration of RA did not significantly enhance the AIV vaccine-induced antibody response against H9N2 virus compared to the group that received the vaccine alone. However, RA supplementation enhanced the frequency of macrophages (KUL01+), expression of inflammatory cytokines and production of IFN-γ by splenocytes. In addition, RA administration reduced oral shedding of AIV on day 5 post-infection. In conclusion, these findings suggest that RA can be supplemented in ovo to enhance AIV vaccine efficacy against LPAIV.

Retinoic Acid-PPARα Mediates ß-Carotene Resistance to Placental Dysfunction Induced by Deoxynivalenol.

Deoxynivalenol (DON), one of the most polluted mycotoxins in the environment and food, has been proven to have strong embryonic and reproductive toxicities. However, the effects of DON on placental impairment and effective interventions are still unclear. This study investigated the effect of ß-carotene on placental functional impairment and its underlying molecular mechanism under DON exposure. Adverse pregnancy outcomes were caused by intraperitoneal injection of DON from 13.5 to 15.5 days of gestation in mice, resulting in higher enrichment of DON in placenta than in other tissue samples. Interestingly, 0.1% ß-carotene dietary supplementation could significantly alleviate DON-induced pregnancy outcomes. Additionally, in vivo and in vitro placental barrier models demonstrated the association of DON-induced placental function impairment with placental permeability barrier disruption, angiogenesis impairment, and oxidative stress induction. Moreover, ß-carotene regulated DON-induced placental toxicity by activating the expressions of claudin 1, zonula occludens-1, and vascular endothelial growth factor-A through retinoic acid-peroxisome proliferator-activated receptor α signaling.

Combined dandelion extract and all-trans retinoic acid induces cytotoxicity in human breast cancer cells.

Breast cancer is one of the most prevalent and deadly cancers among women worldwide. Recently, natural compounds have been widely used for the treatment of breast cancer. Present study evaluated antiproliferative and anti-metastasis activities of two natural compounds of dandelion and all-trans-retinoic acid (ATRA) in human MCF-7 and MDA-MB231 breast cancer cells. We also evaluated the expression of MMP-2, MMP-9, IL-1ß, p53, NM23 and KAI1 genes. Data showed a clear additive cytotoxic effect in concentrations of 40 µM ATRA with 1.5 and 4 mg/ml of dandelion extract in MCF-7 and MDA-MB231 cells, respectively. In both cell lines, compared with the untreated cells, the expression levels of MMP-9 and IL-1ß were significantly decreased while p53 and KAI1 expression levels were increased. Besides, MMP-2 and NM23 had different expressions in the two studied cell lines. In conclusion, dandelion/ATRA co-treatment, in addition to having strong cytotoxic effects, has putative effects on the expression of anti-metastatic genes in both breast cancer cells.

Interference with the retinoic acid signalling pathway inhibits the initiation of teeth and caudal primary scales in the small-spotted catshark Scyliorhinus canicula.

The retinoic acid (RA) pathway was shown to be important for tooth development in mammals, and suspected to play a key role in tooth evolution in teleosts. The general modalities of development of tooth and "tooth-like" structures (collectively named odontodes) seem to be conserved among all jawed vertebrates, both with regard to histogenesis and genetic regulation. We investigated the putative function of RA signalling in tooth and scale initiation in a cartilaginous fish, the small-spotted catshark Scyliorhinus canicula. To address this issue, we identified the expression pattern of genes from the RA pathway during both tooth and scale development and performed functional experiments by exposing small-spotted catshark embryos to exogenous RA or an inhibitor of RA synthesis. Our results showed that inhibiting RA synthesis affects tooth but not caudal primary scale development while exposure to exogenous RA inhibited both. We also showed that the reduced number of teeth observed with RA exposure is probably due to a specific inhibition of tooth bud initiation while the observed effects of the RA synthesis inhibitor is related to a general delay in embryonic development that interacts with tooth development. This study provides data complementary to previous studies of bony vertebrates and support an involvement of the RA signalling pathway toolkit in odontode initiation in all jawed vertebrates. However, the modalities of RA signalling may vary depending on the target location along the body, and depending on the species lineage.

Folic acid supplementation rescues bladder injury in fetal rats with myelomeningocele.

BACKGROUND: Bladder dysfunction has been linked to the progression of renal failure in children with neurogenic bladder (NB) dysfunction. The purpose of this study was to determine whether bladder injuries in fetal rats with myelomeningocele (MMC) may be treated with folic acid. METHODS: Pregnant Sprague-Dawley rats were randomly divided into three groups. On the 10th day of gestation, pregnant rats were intragastrically injected with all-trans retinoic acid (ATRA) (60 mg/kg) to induce MMC fetal rats. The same amount of olive oil was put into the control group to create normal fetal rats. The rats in the rescue group were given folic acid (40 mg/kg) by gavage 0.5 and 12 hr after ATRA therapy. Bladders were obtained via cesarean section on embryonic day E20.5 and examined for MMC. The histology of the fetuses was examined using hematoxylin and eosin staining, and immunohistochemistry (IHC) was utilized to determine the expression of α-smooth muscle actin (α-SMA) and neuron-specific nuclear-binding protein (NeuN). Furthermore, the levels of neuromuscular development-related and apoptotic proteins were determined by western blotting. RESULTS: The incidence of MMC in the model group was 60.6% (20/33) while it was much lower in the rescue group (21.4%). In comparison to the model group, the weight and crown-rump length of the fetal rats in the rescue group were significantly improved. IHC revealed that there was no significant difference in the expression of α-SMA and NeuN between the control and ATRA groups, while the expression levels decreased significantly in the MMC group. Western blot analysis showed that there was no significant difference between the model and ATRA groups, but the expression of the α-SMA protein and the ß3-tubulin was much lower in the MMC group than in the control group. After the administration of folic acid, the α-SMA and ß3-tubulin proteins considerably increased in the folic acid-rescued MMC group and folic acid-rescued ATRA group. Meanwhile, in the control group, the expression of cleaved caspase-3 in the bladder tissue was significantly higher, and the expression of poly (ADP-ribose) polymerase (PARP) protein was significantly lower compared to the control group. Folic acid therapy reduced cleaved caspase-3 expression while increasing PARP expression in comparison to the MMC group. CONCLUSIONS: NB in MMC fetal rats is associated with the reduction of bladder nerve and smooth muscle-related protein synthesis. However, folic acid therapy can help improve these functional deficiencies. Folic acid also exhibits strong anti-apoptotic properties against NB in MMC fetal rats.

Efficacy and safety of a novel triple combination cream compared to Kligman's trio for melasma: A 24-week double-blind prospective randomized controlled trial.

BACKGROUND: Kligman's trio (KT), combining hydroquinone, retinoic acid and corticosteroid, is considered as the gold standard treatment of melasma. Its efficacy has never been matched before, but it is tempered by frequent adverse effects. OBJECTIVE: To assess the efficacy and tolerance of a New Trio (NT) combination with isobutylamido-thiazolyl-resorcinol, retinoic acid and cortosteroid compared to KT. METHODS: We conducted a 24-week monocentric trial, randomized, double-blind, controlled versus KT, with 40 melasma patients. NT and KT were applied for 12 weeks and associated with the same sunscreen applied for 24 weeks. The primary endpoint was the modified Melasma Area Severity Index (mMASI) at 12 weeks. Patient quality of life was investigated using MelasQoL. RESULTS: After 12 weeks, KT and NT groups both demonstrated a significant improvement in mMASI, respectively -2.84 (SE 0.69, p < 0.0002) and -4.33 (SE 0.71, p < 0.0001). The mean difference between the two groups was -1.49 (IC 95% -3.52 to 0.54, p = 0.14). MelasQoL improvement was -6.66 (SE 3.29, p = 0.0515) with KT and -12.57 (SE 3.29, p = 0.0006) with NT. CONCLUSION: The NT combination appears to be an effective treatment option for treating melasma and could be considered as a well-tolerated alternative to KT.

Retinoic acid and proteotoxic stress induce AML cell death overcoming stromal cell protection.

BACKGROUND: Acute myeloid leukemia (AML) patients bearing the ITD mutation in the tyrosine kinase receptor FLT3 (FLT3-ITD) present a poor prognosis and a high risk of relapse. FLT3-ITD is retained in the endoplasmic reticulum (ER) and generates intrinsic proteotoxic stress. We devised a strategy based on proteotoxic stress, generated by the combination of low doses of the differentiating agent retinoic acid (R), the proteasome inhibitor bortezomib (B), and the oxidative stress inducer arsenic trioxide (A). METHODS: We treated FLT3-ITD+ AML cells with low doses of the aforementioned drugs, used alone or in combinations and we investigated the induction of ER and oxidative stress. We then performed the same experiments in an in vitro co-culture system of FLT3-ITD+ AML cells and bone marrow stromal cells (BMSCs) to assess the protective role of the niche on AML blasts. Eventually, we tested the combination of drugs in an orthotopic murine model of human AML. RESULTS: The combination RBA exerts strong cytotoxic activity on FLT3-ITD+ AML cell lines and primary blasts isolated from patients, due to ER homeostasis imbalance and generation of oxidative stress. AML cells become completely resistant to the combination RBA when treated in co-culture with BMSCs. Nonetheless, we could overcome such protective effects by using high doses of ascorbic acid (Vitamin C) as an adjuvant. Importantly, the combination RBA plus ascorbic acid significantly prolongs the life span of a murine model of human FLT3-ITD+ AML without toxic effects. Furthermore, we show for the first time that the cross-talk between AML and BMSCs upon treatment involves disruption of the actin cytoskeleton and the actin cap, increased thickness of the nuclei, and relocalization of the transcriptional co-regulator YAP in the cytosol of the BMSCs. CONCLUSIONS: Our findings strengthen our previous work indicating induction of proteotoxic stress as a possible strategy in FLT3-ITD+ AML therapy and open to the possibility of identifying new therapeutic targets in the crosstalk between AML and BMSCs, involving mechanotransduction and YAP signaling.

Loss of Twist1 and balanced retinoic acid signaling from the meninges causes cortical folding in mice.

Secondary lissencephaly evolved in mice due to effects on neurogenesis and the tangential distribution of neurons. Signaling pathways that help maintain lissencephaly are still poorly understood. We show that inactivating Twist1 in the primitive meninges causes cortical folding in mice. Cell proliferation in the meninges is reduced, causing loss of arachnoid fibroblasts that express Raldh2, an enzyme required for retinoic acid synthesis. Regionalized loss of Raldh2 in the dorsolateral meninges is first detected when folding begins. The ventricular zone expands and the forebrain lengthens at this time due to expansion of apical radial glia. As the cortex expands, regionalized differences in the levels of neurogenesis are coupled with changes to the tangential distribution of neurons. Consequentially, cortical growth at and adjacent to the midline accelerates with respect to more dorsolateral regions, resulting in cortical buckling and folding. Maternal retinoic acid supplementation suppresses cortical folding by normalizing forebrain length, neurogenesis and the tangential distribution of neurons. These results suggest that Twist1 and balanced retinoic acid signaling from the meninges are required to maintain normal levels of neurogenesis and lissencephaly in mice.

Deregulation of All-Trans Retinoic Acid Signaling and Development in Cancer.

Cancer stem cells are the root cause of cancer, which, in essence, is a developmental disorder. All-trans retinoic acid (ATRA) signaling via ligand-activation of the retinoic acid receptors (RARs) plays a crucial role in tissue patterning and development during mammalian embryogenesis. In adults, active RARγ maintains the pool of hematopoietic stem cells, whereas active RARα drives myeloid cell differentiation. Various findings have revealed that ATRA signaling is deregulated in many cancers. The enzymes for ATRA synthesis are downregulated in colorectal, gastric, lung, and oropharyngeal cancers. ATRA levels within breast, ovarian, pancreatic, prostate, and renal cancer cells were lower than within their normal counterpart cells. The importance is that 0.24 nM ATRA activates RARγ (for stem cell stemness), whereas 100 times more is required to activate RARα (for differentiation). Moreover, RARγ is an oncogene regarding overexpression within colorectal, cholangiocarcinoma, hepatocellular, ovarian, pancreatic, and renal cancer cells. The microRNA (miR) 30a-5p downregulates expression of RARγ, and miR-30a/miR-30a-5p is a tumor suppressor for breast, colorectal, gastric, hepatocellular, lung, oropharyngeal, ovarian, pancreatic, prostate, and renal cancer. These complementary findings support the view that perturbations to ATRA signaling play a role in driving the abnormal behavior of cancer stem cells. Targeting ATRA synthesis and RARγ has provided promising approaches to eliminating cancer stem cells because such agents have been shown to drive cell death.

Factors and Molecular Mechanisms of Vitamin A and Childhood Obesity Relationship: A Review.

Childhood obesity has become a public health concern. As the importance of vitamin A (VA) in the body has become increasingly acknowledged, there is limited clinical trial evidence to substantiate the association between VA and childhood obesity. Vitamin A deficiency (VAD) increases the risk of childhood obesity, a finding consistently reported in pregnant women. VA could regulate the adipogenic process, inflammation, oxidative stress and metabolism-related gene expression in mature adipocytes. VAD disrupts the balance of obesity-related metabolism, thus affecting lipid metabolism and insulin regulation. Conversely, VA supplementation has a major impact on efficacy in obesity, and obese individuals typically have a lower VA status than normal-weight individuals. Several studies have attempted to identify the genetic and molecular mechanisms underlying the association between VA and obesity. In this review, we summarize and discuss recent new developments focusing on retinol, retinoic acid, and RBP4 and elucidate and provide an overview of the complex interrelationships between these critical components of VA and childhood obesity. However, the causal relationship between VA status and childhood obesity remains unclear. It is also unknown whether VA supplementation improves the overall obesogenic metabolic profile.

Ascorbic acid induces MLC2v protein expression and promotes ventricular-like cardiomyocyte subtype in human induced pluripotent stem cells derived cardiomyocytes.

Introduction: The potentially unlimited number of cardiomyocyte (CMs) derived from human induced pluripotent stem cells (hiPSCs) in vitro facilitates high throughput applications like cell transplantation for myocardial repair, disease modelling, and cardiotoxicity testing during drug development. Despite promising progress in these areas, a major disadvantage that limits the use of hiPSC derived CMs (hiPSC-CMs) is their immaturity. Methods: Three hiPSC lines (PCBC-hiPSC, DP3-hiPSCs, and MLC2v-mEGFP hiPSC) were differentiated into CMs (PCBC-CMs, DP3-CMs, and MLC2v-CMs, respectively) with or without retinoic acid (RA). hiPSC-CMs were either maintained up to day 30 of contraction (D30C), or D60C, or purified using lactate acid and used for experiments. Purified hiPSC-CMs were cultured in basal maturation medium (BMM) or BMM supplemented with ascorbic acid (AA) for 14 days. The AA treated and non-treated hiPSC-CMs were characterized for sarcomeric proteins (MLC2v, TNNI3, and MYH7), ion channel proteins (Kir2.1, Nav1.5, Cav1.2, SERCA2a, and RyR), mitochondrial membrane potential, metabolomics, and action potential. Bobcat339, a selective and potent inhibitor of DNA demethylation, was used to determine whether AA promoted hiPSC-CM maturation through modulating DNA demethylation. Results: AA significantly increased MLC2v expression in PCBC-CMs, DP3-CMs, MLC2v-CMs, and RA induced atrial-like PCBC-CMs. AA treatment significantly increased mitochondrial mass, membrane potential, and amino acid and fatty acid metabolism in PCBC-CMs. Patch clamp studies showed that AA treatment induced PCBC-CMs and DP3-CMs adaptation to a ventricular-like phenotype. Bobcat339 inhibited MLC2v protein expression in AA treated PCBC-CMs and DP3-CMs. DNA demethylation inhibition was also associated with reduced TET1 and TET2 protein expressions and reduced accumulation of the oxidative product, 5 hmC, in both PCBC-CMs and DP3-CMs, in the presence of AA. Conclusions: Ascorbic acid induced MLC2v protein expression and promoted ventricular-like CM subtype in hiPSC-CMs. The effect of AA on hiPSC-CM was attenuated with inhibition of TET1/TET2 mediated DNA demethylation.