Dipak Kumar Sarkar

Background: We have recently shown that estrogen‐induced prolactin‐secreting pituitary tumors are aggressive in prenatal alcohol‐exposed female rats. In this study, we investigated whether similar tumor aggressiveness occurs in estrogen‐treated prenatal alcohol‐exposed male rats. Methods: Pregnant Fischer 344 rats were fed from gestational days 7 and 21 with a liquid diet containing ethanol 6.7% v/v (AF), pair‐fed with an isocaloric liquid diet (PF), or fed chow ad libitum (AD). Alcohol‐fed dams exhibited a blood alcohol concentration of 120–150 mg/dL 2 h after the last feeding. Male offspring were orchiectomized at 60 days of age and implanted subcutaneously with estradiol implants. Four months after the estradiol implants, rats were sacrificed, and pituitary tumor tissues were collected. Tumor cells were isolated and cultured for analysis. Results: Pituitary tumor cells from AF males exhibited stem‐like cell properties and showed elevated expression of stem cell regulatory genes and proteins (SOX‐2, OCT‐4, KLF4, SNAIL‐1, and Nestin), tumor aggressiveness markers (MMP‐9, CD44, CD34, PTTG, FGFR4, Ki‐67, N‐Cadherin), and prolactin compared to those from AD and PF controls. AF cells also had a higher cell proliferation rate, increased invasiveness, and colony formation compared to those in AD and PF cells, indicating more aggressive cancer cells than control cells. Notably, AF cells had a higher expression of developmental pluripotency‐associated 4 (Dppa4), a gene we recently identified as upregulated in aggressive tumors and in fetal alcohol‐exposed animals. Conclusions: These findings are consistent with our previous observations in estrogen‐treated AF female rats. These results support the hypothesis that prenatal alcohol exposure programs the pituitary epithelium toward a mesenchymal stem cell‐like phenotype, contributing to the development of aggressive pituitary prolactinomas in both sexes.

Microglia, a type of resident immune cells within the central nervous system, have been implicated in ethanol-activated neuronal death of the stress regulatory proopiomelanocortin (POMC) neuron-producing β-endorphin peptides in the hypothalamus in a postnatal rat model of fetal alcohol spectrum disorders. We determined if microglial extracellular vesicles (exosomes) are involved in the ethanol-induced neuronal death of the β-endorphin neuron via secreting elevated levels of the chemokine monocyte chemoattractant protein 1 (MCP1), a key regulator of neuroinflammation. We employed an in vitro model, consisting of primary culture of hypothalamic microglia prepared from postnatal day 2 (PND2) rat hypothalami and treated with or without 50 mM ethanol for 24 h, and an in vivo animal model in which microglia were obtained from hypothalami of PND6 rats fed daily with 2.5 mg/kg ethanol or control milk formula for five days prior to use. Exosomes were extracted and characterized with nanosight tracking analysis (NTA), transmission electron microscopy and western blot. Chemokine multiplex immunoassay and ELISA were used for quantitative estimation of MCP1 level. Neurotoxic ability of exosome was tested using primary cultures of β-endorphin neurons and employing nucleosome assay and immunocytochemistry. Elevated plus maze, open field and restraint tests were used to assess anxiety-related behaviors. Ethanol elevated MCP1 levels in microglial exosomes both in vitro and in vivo models. Ethanol-activated microglial exosomes when introduced into primary cultures of β-endorphin neurons, increased cellular levels of MCP1 and the chemokine receptor CCR2 related signaling molecules including inflammatory cytokines and apoptotic genes as well as apoptotic death of β-endorphin neurons. These effects of microglial exosomes on β-endorphin neurons were suppressed by a CCR2 antagonist RS504393. Furthermore, RS504393 when injected in postnatal rats prior to feeding with ethanol it reduced alcohol-induced β-endorphin neuronal death in the hypothalamus. RS504393 also suppressed corticosterone response to stress and anxiety-like behaviors in postnatally alcohol-fed rats during adult period. These data suggest that alcohol exposures during the developmental period elevates MCP1 levels in microglial exosomes that promote MCP1/CCR2 signaling to increase the apoptosis of β-endorphin neurons and resulting in hormonal and behavioral stress responses.

Background: Prenatal alcohol exposure poses significant risks to offspring mental health. However, the interplay between genetic predispositions to mental health disorders and prenatal alcohol exposure remains incompletely understood, limiting our ability to develop effective interventions for these conditions.Methods: Data from the Adolescent Brain and Cognitive Development (ABCD) Study were analyzed to explore associations between polygenic risk scores (PRS) for mental disorders and maternal alcohol consumption during pregnancy. Logistic regression and structural equation modeling were utilized to assess these relationships.Results: Maternal alcohol consumption after pregnancy awareness was significantly associated with an increased genetic risk for specific mental health disorders, particularly bipolar disorder in offspring. The relationship between maternal alcohol consumption and mental health outcomes was influenced by polygenic risk scores, with both externalizing and internalizing problems being affected.Conclusions: Our findings highlight the specific interaction between increased genetic risk for bipolar disorder and prenatal alcohol exposure in shaping offspring mental health outcomes. The significant associations we observed underscore the importance of considering both polygenic risk scores and prenatal alcohol exposure when assessing mental health risks in children. These insights emphasize the need for targeted interventions that address both genetic predispositions and environmental exposures to better understand and mitigate the impact on offspring mental health.

Prenatal alcohol-exposed (AE) infants and children often demonstrate disrupted sleep patterns, including more frequent awakenings, reduced total sleep time, and more night-to-night sleep variability. Despite the strong connection between sleep patterns and circadian rhythmicity, relatively little is known about circadian rhythm disruptions in individuals with AE. Recently, several reports demonstrated that evaluating the expression patterns of human clock genes in biological fluids could reveal an individual’s circadian phenotype. Human saliva offers an emerging and easily available physiological sample that can be collected non-invasively for core-clock gene transcript analyses. We compared the expression patterns of core-clock genes and their regulatory genes in salivary samples of children aged 6–10 years-old with and without AE during the light cycle between ZT0-ZT11. We isolated the RNA from the samples and measured the expression patterns of core clock genes and clock regulating genes using the human specific primers with quantitative real-time PCR. Analysis of core clock genes expression levels in saliva samples from AE children indicates significantly altered levels in expression of core-clock BMAL1, CLOCK, PER1-3 and CRY1,2, as compared to those in age-matched control children. We did not find any sex difference in levels of clock genes in AE and control groups. Cosinor analysis was used to evaluate the rhythmic pattern of these clock genes, which identified circadian patterns in the levels of core clock genes in the control group but absent in the AE group. The gene expression profile of a salivary circadian biomarker ARRB1 was rhythmic in saliva of control children but was arhythmic in AE children. Altered expression patterns were also observed in clock regulatory genes: NPAS2, NFL3, NR1D1, DEC1, DEC2, and DBP, as well as chromatin modifiers: MLL1, P300, SIRT1, EZH2, HDAC3, and ZR1D1, known to maintain rhythmic expression of core-clock genes. Overall, these findings provide the first evidence that AE disturbs the circadian patten expression of core clock genes and clock-regulatory chromatin modifiers in saliva.

Pituitary neuroendocrine tumors, PitNETs, are often aggressive and precipitate in distant metastases that are refractory to current therapies. However, the molecular mechanism in PitNETs' aggressiveness is not well understood. Developmental pluripotency-associated 4 (DPPA4) is known as a stem cell regulatory gene and overexpressed in certain cancers, but its function in the context of PitNETs' aggressiveness is not known. We employed both rat and human models of PitNETs. In the rat pituitary tumor model (RPT), we used prenatal-alcohol-exposed (PAE) female Fischer rats which developed aggressive PitNETs following estrogen treatment, while in the human pituitary tumor (HPT) model, we used aggressively proliferative cells from pituitary tumors of patients undergone surgery. Various molecular, cellular, and epigenetic techniques were used to determine the role of DPPA4 in PitNETs’ aggressiveness. We show that DPPA4 is overexpressed in association with increased cell stemness factors in aggressive PitNETs of PAE rats and of human patients. Gene-editing experiments demonstrate that DPPA4 increases the expression of cell stemness and tumor aggressiveness genes and promotes proliferation, colonization, migration, and tumorigenic potential of PitNET cells. ChIP assays and receptor antagonism studies reveal that DPPA4 binds to canonical WINTs promoters and increases directly or indirectly the Wnt/β-catenin control of cell stemness, tumor growth, and aggressiveness of PitNETs. Epigenetic studies show involvement of histone methyltransferase in alcohol activation of DPPA4. These findings support a role of DPPA4 in tumor stemness and aggressiveness and provide a preclinical rationale for modulating this stemness regulator for the treatment of PitNETs.

Fetal alcohol spectrum disorders (FASD) are a set of abnormalities caused by prenatal exposure to ethanol and are characterized by developmental defects in the brain that lead to various overt and non-overt physiological abnormalities. Growing evidence suggests that in utero alcohol exposure induces functional and structural abnormalities in gliogenesis and neuron–glia interactions, suggesting a possible role of glial cell pathologies in the development of FASD. However, the molecular mechanisms of neuron–glia interactions that lead to the development of FASD are not clearly understood. In this review, we discuss glial cell pathologies with a particular emphasis on microglia, primary resident immune cells in the brain. Additionally, we examine the involvement of several neuroimmune molecules released by glial cells, their signaling pathways, and epigenetic mechanisms responsible for FASD-related alteration in brain functions. Growing evidence suggests that extracellular vesicles (EVs) play a crucial role in the communication between cells via transporting bioactive cargo from one cell to the other. This review emphasizes the role of EVs in the context of neuron–glia interactions during prenatal alcohol exposure. Finally, some potential applications involving nutritional, pharmacological, cell-based, and exosome-based therapies in the treatment of FASD are discussed.

Objectives: This review aims to determine the connection between developmental alcohol exposure and its potential impact on Alzheimer's disease (AD) later in life. We employ a network meta-analysis approach and examine gene fold changes from literature and Gene Expression Omnibus (GEO) datasets. Our goal is to investigate whether prenatal alcohol exposure (PAE) and/or adolescent alcohol exposure (AAE) could activate specific neuroinflammatory genes, potentially increasing the risk of AD development. Content: We conducted a comprehensive analysis of brain datasets using a network meta-analysis approach. By synthesizing gene fold changes from literature and GEO datasets, we examined the potential impact of developmental alcohol exposure on increased risk of developing AD in the future. Summary: Our findings reveal significant associations between alcohol exposure and critical functional categories and diseases in the brain. Alcohol exposure was strongly linked to the “Inflammatory Response” and “Nervous System Development and Function” categories, indicative of inflammatory reactions in the brain and detrimental effects on nervous system integrity. Furthermore, we observed links with “Organismal Injury and Abnormalities” and “Cell Death and Survival.” Pathway analysis revealed dysregulation in neuroinflammatory, ERK/MAPK signaling, amyloid processing, IL-1 signaling and calcium signaling pathways, suggesting their potential involvement in alcohol-induced neurotoxicity. Outlook: This review highlights the necessity of recognizing developmental alcohol exposure as a potential risk factor for AD and shed light on the underlying mechanisms that may contribute to alcohol-induced neurotoxicity. By expanding our understanding of these mechanisms, we can better address the complex relationship between developmental alcohol exposure and neurodegenerative disorders like AD.

Background: Alcohol drinking during pregnancy often adversely affects brain development among offspring, inducing persistent central nervous system dysfunction. However, it is unknown whether fetal alcohol exposure (FAE) promotes the biochemical characteristics of Alzheimer's disease in offspring.Methods: We used a first‐ and second‐trimester human equivalent rat model of FAE that involves feeding a liquid diet containing 6.7% v/v ethanol from gestational days 7 through 21 in Fischer‐344 rats. Control rats were fed an isocaloric liquid diet or rat chow ad libitum. Pups were weaned on postnatal day 21 and housed by sex. They were used for behavioral and biochemical studies at about 12 months of age. Only one male or one female offspring from a litter was included in each experimental group.Results: Fetal alcohol‐exposed offspring had poorer learning and memory functions than controls. The experimental animals, both male and female, also had elevated levels of acetylcholinesterase (AChE) activity, hyperphosphorylated‐tau protein, β‐amyloid (Aβ) and Aβ1‐42 proteins, β‐site amyloid precursor protein cleaving enzyme 1 (BACE1), and Unc‐5 netrin receptor C (UNC5C) proteins in the cerebral cortex and hippocampus at 12 months of age.Conclusions: These findings show that FAE increases the expression of some of the biochemical and behavioral phenotypes of Alzheimer's disease.