IGF2: epigenetic regulation and role in development and disease

Circ_0001361/miR-490-5p/IGF2 Axis Regulates the Viability and Apoptosis of Neuroblastoma Cells

BACKGROUND

Circular RNAs (circRNAs) are involved in the neuroblastoma (NB) development. Objectie: The study aimed to determine the biological behaviors of circ_0001361 and explore its underlying mechanism in NB.

METHODS

The circ_0001361, miR-490-5p, and IGF2 levels were measured using quantitative real-time polymerase chain reaction. Cellular processes were analyzed using MTT assay or fluorescence-activated cell sorting (FACS). Phosphorylated (p)-PI3K, p-AKT, Bax, and caspase-3 were tested by western blot. Dual-luciferase reporter analysis together with RNA pull-down analysis were utilized to evaluate the correlation of miR-490-5p and circ_0001361 or IGF2.

RESULTS

The results in this study illustrated that an elevation of circ_0001361 levels was observed in NB. Depletion of circ_0001361 suppressed the viability but facilitated apoptosis of NB cells. Circ_0001361 sponged miR-490-5p, which targeted to regulate IGF2. Inhibition of miR-490-5p rescued the effect induced by circ_0001361 knockdown, while deletion of IGF2 rescued the effect induced by the miR-490-5p inhibitor.

CONCLUSIONS

In summary, a loss of circ_0001361 inhibited NB progression via targeting the miR-490-5p/IGF2 axis, suggesting that circ_0001361 may be a novel therapeutical target of NB.

IGF2 contributes to the immunomodulatory effects of exosomes from endometrial regenerative cells on experimental colitis

BACKGROUND

Exosomes derived from endometrial regenerative cells (ERC-Exos) can inherit the immunomodulatory function from ERCs, however, whether ERC-Exos exhibit such effect on inflammatory bowel diseases with mucosal immune dysregulation has not been explored. Insulin-like growth factor-Ⅱ (IGF2) is considered to possess the potential to induce an anti-inflammatory phenotype in immune cells. In this study, the contribution of IGF2 in mediating the protective efficacy of ERC-Exos on colitis was investigated.

METHODS

Lentiviral transfection was employed to obtain IGF2-specific knockout ERC-Exos (IGF2-/--ERC-Exos). Experimental colitis mice induced by dextran sulfate sodium (DSS) were divided into the phosphate-buffered saline (untreated), ERC-Exos-treated and IGF2-/--ERC-Exos-treated groups. Colonic histopathological analysis and intestinal barrier function were explored. The infiltration of CD4+ T cells and dendritic cells (DCs) were analyzed by immunofluorescence staining and flow cytometry. The maturation and function of bone marrow-derived dendritic cells (BMDCs) in different exosome administrations were evaluated by flow cytometry, ELISA and the coculture system, respectively.

RESULTS

Compared with the untreated group, ERC-Exos treatment significantly attenuated DSS-induced weight loss, bloody stools, shortened colon length, pathological damage, as well as repaired the weakened intestinal mucosal barrier, including promoting the goblet cells retention, restoring the intestinal barrier integrity and enhancing the expression of tight junction proteins, while the protective effect of exosomes was impaired with the knockout of IGF2 in ERC-Exos. Additionally, IGF2-expressing ERC-Exos decreased the proportions of Th1 and Th17, increased the proportions of Treg, as well as attenuated DC infiltration and maturation in mesenteric lymph nodes and lamina propria of the colitis mice. ERC-Exos were also observed to be phagocytosed by BMDCs and IGF2 is responsible for the modulating effect of ERC-Exos on BMDCs in vitro.

CONCLUSIONS

Exosomes derived from ERCs can exert a therapeutic effect on experimental colitis with remarkable alleviation of the intestinal barrier damage and the abnormal mucosal immune responses. We emphasized that IGF2 plays a critical role for ERC-Exos mediated immunomodulatory function and protection against colitis.

Dynamics of Neurogenic Signals as Biological Switchers of Brain Plasticity

The discovery of adult neurogenesis in the middle of the past century is considered one of the most important breakthroughs in neuroscience. Despite its controversial nature, this discovery shaped our concept of neural plasticity, revolutionizing the way we look at our brains. In fact, after the discovery of adult neurogenesis, we started to consider the brain as something even more dynamic and highly adaptable. In neurogenic niches, adult neurogenesis is supported by neural stem cells (NSCs). These cells possess a unique set of characteristics such as being quiescent for long periods while actively sensing and reacting to their surroundings to influence a multitude of processes, including the generation of new neurons and glial cells. Therefore, NSCs can be viewed as sentinels to our brain's homeostasis, being able to replace damaged cells and simultaneously secrete numerous factors that restore regular brain function. In addition, it is becoming increasingly evident that NSCs play a central role in memory formation and consolidation. In this review, we will dissect how NSCs influence their surroundings through paracrine and autocrine types of action. We will also depict the mechanism of action of each factor. Finally, we will describe how NSCs integrate different and often opposing signals to guide their fate.

Impact of Organochlorine Pesticides Exposure on Histone Modification H3K9ac: Implications for Unexplained Recurrent Miscarriage

Epigenetic alterations, changes in gene expression without DNA sequence modifications, are associated with various health disorders, including reproductive health issues. These alterations can be influenced by environmental factors such as pesticides. This study aimed to explore the relationship between exposure to Organochlorine Pesticides (OClPs) and the histone modification mark H3K9ac in the placenta and fetal tissue, in the context of unexplained recurrent miscarriage (URM). In the case-control study, serum samples from 73 women with URM and 30 healthy women were examined for the presence of OClPs, which include 2,4-DDT, 2,4-DDE, 4,4-DDT, 4,4-DDE, α-HCH, β-HCH, and γ-HCH, using gas chromatography. Western blot analysis was used to assess H3K9ac expression in placental and fetal tissues. In the URM group, significant increases were observed in the values of α-HCH, β-HCH, 2,4-DDE, and 4,4-DDE, as well as in the concentration of total OClPs (Ʃ3HCH, Ʃ2DDE, Ʃ2DDT, and Ʃ7OClP), compared to controls. While H3K9ac levels in fetal tissue showed no significant difference, a notable decrease was found in the placental tissue of the URM. In the placenta tissue of URM, logistic regression analysis also revealed a significant inverse correlation between the toxins α-HCH, 2,4-DDE, 4,4-DDE, 4,4-DDT, total OClPs, and reduced H3K9ac expression. Our findings suggest that OClPs exposure may contribute to URM by reducing H3K9ac expression in the placenta, potentially affecting placental growth and immune tolerance. This underscores the need for further investigation into the involved mechanisms and potential therapeutic interventions, and the importance of OClPs regulation for reproductive health protection.

Transcriptome analysis of large yellow croaker (Larimichthys crocea) at different growth rates

The unsynchronized growth of the large yellow croaker (Larimichthys crocea), which impacts growth efficiency, poses a challenge for aquaculture practitioners. In our study, juvenile stocks of large yellow croaker were sorted by size after being cultured in offshore cages for 4 months. Subsequently, individuals from both the fast-growing (FG) and slow-growing (SG) groups were sampled for analysis. High-throughput RNA-Seq was employed to identify genes and pathways that are differentially expressed during varying growth rates, which could suggest potential physiological mechanisms that influence growth rate. Our transcriptome analysis identified 382 differentially expressed genes (DEGs), comprising 145 upregulated and 237 downregulated genes in comparison to the SG group. GO and KEGG enrichment analyses indicated that these DEGs are predominantly involved in signal transduction and biochemical metabolic pathways. Quantitative PCR (qPCR) results demonstrated that cat, fasn, idh1, pgd, fgf19, igf2, and fads2 exhibited higher expression levels, whereas gadd45b and gadd45g showed lower expression compared to the slow-growing group. In conclusion, the differential growth rates of large yellow croaker are intricately associated with cellular proliferation, metabolic rates of the organism, and immune regulation. These findings offer novel insights into the molecular mechanisms and regulatory aspects of growth in large yellow croaker and enhance our understanding of growth-related genes.

IGF Signaling in the Heart in Health and Disease

One of the most vital processes of the body is the cardiovascular system's proper operation. Physiological processes in the heart are regulated by the balance of cardioprotective and pathological mechanisms. The insulin-like growth factor system (IGF system, IGF signaling pathway) plays a pivotal role in regulating growth and development of various cells and tissues. In myocardium, the IGF system provides cardioprotective effects as well as participates in pathological processes. This review summarizes recent data on the role of IGF signaling in cardioprotection and pathogenesis of various cardiovascular diseases, as well as analyzes severity of these effects in various scenarios.

Identification of IGF2 promotes skin wound healing by co-expression analysis

Oral mucosa is an ideal model for studying scarless wound healing. Researchers have shown that the key factors which promote scarless wound healing already exist in basal state of oral mucosa. Thus, to identify the other potential factors in basal state of oral mucosa will benefit to skin wound healing. In this study, we identified eight gene modules enriched in wound healing stages of human skin and oral mucosa through co-expression analysis, among which the module M8 was only module enriched in basal state of oral mucosa, indicating that the genes in module M8 may have key factors mediating scarless wound healing. Through bioinformatic analysis of genes in module M8, we found IGF2 may be the key factor mediating scarless wound healing of oral mucosa. Then, we purified IGF2 protein by prokaryotic expression, and we found that IGF2 could promote the proliferation and migration of HaCaT cells. Moreover, IGF2 promoted wound re-epithelialization and accelerated wound healing in a full-thickness skin wound model. Our findings identified IGF2 as a factor to promote skin wound healing which provide a potential target for wound healing therapy in clinic.

Sex and fetal genome influence gene expression in pig endometrium at the end of gestation

BACKGROUND

A fine balance of feto-maternal resource allocation is required to support pregnancy, which depends on interactions between maternal and fetal genetic potential, maternal nutrition and environment, endometrial and placental functions. In particular, some imprinted genes have a role in regulating maternal-fetal nutrient exchange, but few have been documented in the endometrium. The aim of this study is to describe the expression of 42 genes, with parental expression, in the endometrium comparing two extreme breeds: Large White (LW); Meishan (MS) with contrasting neonatal mortality and maturity at two days of gestation (D90-D110). We investigated their potential contribution to fetal maturation exploring genes-fetal phenotypes relationships. Last, we hypothesized that the fetal genome and sex influence their endometrial expression. For this purpose, pure and reciprocally crossbred fetuses were produced using LW and MS breeds. Thus, in the same uterus, endometrial samples were associated with its purebred or crossbred fetuses.

RESULTS

Among the 22 differentially expressed genes (DEGs), 14 DEGs were differentially regulated between the two days of gestation. More gestational changes were described in LW (11 DEGs) than in MS (2 DEGs). Nine DEGs were differentially regulated between the two extreme breeds, highlighting differences in the regulation of endometrial angiogenesis, nutrient transport and energy metabolism. We identified DEGs that showed high correlations with indicators of fetal maturation, such as ponderal index at D90 and fetal blood fructose level and placental weight at D110. We pointed out for the first time the influence of fetal sex and genome on endometrial expression at D90, highlighting AMPD3, CITED1 and H19 genes. We demonstrated that fetal sex affects the expression of five imprinted genes in LW endometrium. Fetal genome influenced the expression of four genes in LW endometrium but not in MS endometrium. Interestingly, both fetal sex and fetal genome interact to influence endometrial gene expression.

CONCLUSIONS

These data provide evidence for some sexual dimorphism in the pregnant endometrium and for the contribution of the fetal genome to feto-maternal interactions at the end of gestation. They suggest that the paternal genome may contribute significantly to piglet survival, especially in crossbreeding production systems.

Transcriptomic profiling reveals the immune response mechanism of the Thamnaconus modestus induced by the poly (I:C) and LPS

Aquatic animals immune response to pathogenic is a hotspot and related to high-quality development of aquaculture industry and the conservation of fisheries resources. Thamnaconus modestus is an important commercial and economical species which is suffering from various pathogens but by now lack relevant research about revealing the immune response mechanism to the pathogens invasion. In the study, the polyriboinosinic polyribocytidylic acid [poly (I:C)] and Lipopolysaccharides (LPS), respective mimics of viral and bacterial infections, were used to demonstrate the immune response of the species via transcriptome analysis. The results showed that T. modestus had sensitive responses to the viral analog infection at 6 h and 48 h, and at 6 h, the first five major functional genes were NFKBIA, IL1B, JUN, IGH, FOS, and at 48 h, the genes were NFKBIA, IL1B, JUN, IGH, FOS. The genes IL1B, IRF3, PTGS2, THBS1 could helping the fish to fight against the bacterial infection in both the times. Similarly for the bacterial infection, the species had a sensitive response at 6 h, and the first five major functional genes were NFKBIA, JUN, FOS, L1B, GRIN2C. Our study provided an insight about the immune response mechanism of this species and demonstrated that if need for treatment of the virus and bacteria by the biotechnology, the artificial interferential time would be suggested before 6 h since the pathological features occur and the genes NFKBIA, JUN, IL1B, FOS, TRAF2, IL8, SOCS3, PTGS2 should be payed more attention.

The role of MAPK, notch and Wnt signaling pathways in papillary thyroid cancer: Evidence from a systematic review and meta-analyzing microarray datasets employing bioinformatics knowledge and literature

Papillary thyroid cancer (PTC) is a prevalent kind of thyroid cancer (TC), with the risk of metastasis increasing faster than any other malignancy. So, understanding the role of PTC in pathogenesis requires studying the various gene expressions to find out which particular molecular biomarkers will be helpful. The authors conducted a comprehensive search on the PubMed microarray database and a meta-analysis approach on the remaining ones to determine the differentially expressed genes between PTC and normal tissues, along with the analyses of overall survival (OS) and recurrence-free survival (RFS) rates in patients with PTC. We considered the associated genes with MAPK, Wnt, and Notch signaling pathways. Two GEO datasets have been included in this research, considering inclusion and exclusion criteria. Nineteen genes were found to have higher differences through the meta-analysis procedure. Among them, ten genes were upregulated, and nine genes were downregulated. The expression of 19 genes was examined using the GEPIA2 database, and the Kaplan-Meier plot statistics were used to analyze RFS and the OS rates. We discovered seven significant genes with the validation: PRICKLE1, KIT, RPS6KA5, GADD45B, FGFR2, FGF7, and DTX4. To further explain these findings, it was discovered that the mRNA expression levels of these seven genes and the remaining 12 genes were shown to be substantially linked with the results of the experimental literature investigations on the PTC. Our research found nineteen panels of genes that could be involved in the PTC progression and metastasis and the immune system infiltration of these cancers.

Nonadditive and allele-specific expression of ghrelin in hybrid tilapia

Background

Interspecies hybridization is an important breeding method to generate fishes with heterosis in aquaculture. Using this method, hybrid Nile tilapia (Oreochromis niloticus, ♀) × blue tilapia (Oreochromis aureus, ♂) has been produced and widely farmed due to its growth and appetite superiorities. However, the genetic mechanism of these advanced traits is still not well understood. Ghrelin is a crucial gene that regulates growth and appetite in fishes. In the present study, we focused on the expression characteristics and its regulation of ghrelin in the hybrid.

Results

The tissue distribution analysis showed that ghrelin was predominantly expressed in the stomach in the hybrid. Ghrelin was more highly expressed in the stomach in the hybrid and Nile tilapia, compared to blue tilapia, showing a nonadditive pattern. Two single-nucleotide polymorphism (SNP) sites were identified including T/C and C/G from the second exon in the ghrelin gene from Nile tilapia and blue tilapia. By pyrosequencing based on the SNP sites, the allele-specific expression (ASE) of ghrelin in the hybrid was assayed. The result indicated that ghrelin in the hybrid showed higher maternal allelic transcript ratios. Fasting significantly increased ghrelin overall expression at 4, 8, 12, 24, and 48 h. In addition, higher maternal allelic transcript ratios were not changed in the fasting hybrids at 48 h. The cis and trans effects were determined by evaluating the overall expression and ASE values in the hybrid. The expression of ghrelin was mediated by compensating cis and trans effects in hybrid.

Conclusion

In summary, the present lines of evidence showed the nonadditive expression of ghrelin in the hybrid tilapia and its regulation by subgenomes, offering new insight into gene expression characteristics in hybrids.

IGF2/IGF2R/Sting signaling as a therapeutic target in DSS-induced ulcerative colitis

Ulcerative colitis is an inflammatory bowel disease with increasing prevalence and incidence. Current treatments for ulcerative colitis are not generally applicative and are often accompanied by side effects. IGF2 is an endogenous protein that plays roles in anti-inflammation and stemness maintenance, but little is known about its mechanism and function in the progression of ulcerative colitis. In this study, mouse recombinant IGF2 was used in a mouse model of ulcerative colitis established by DSS. IGF2 expression was reduced in colon tissues but not plasma of DSS-induced colitis mice. IGF2R expression was also decreased in colitis colons, which was then elevated by recombinant IGF2. Recombinant IGF2 alleviated colon injury in colitis, which was evaluated by colon shortening, body weight loss and DAI score. IGF2 treatment also relieved the inflammatory response in colitis, which was assessed by the spleen weight index, MPO activity and proinflammatory cytokine expression and was also detected in LPS-stimulated RAW264.7 cells in vitro. Moreover, IGF2R was predicted and further verified to interact with the Sting protein, and the cGAS-Sting pathway as a key pathway for stemness regulation, was upregulated in colonic colons, which was blocked by IGF2 treatment. Additionally, IGF2 treatment can maintain colonic stemness and further repair colonic tight junction function in DSS-induced colitis. In conclusion, IGF2/IGF2R downregulated the cGAS-Sting pathway to sustain colonic stemness and barrier integrity to protect against ulcerative colitis induced by DSS.

Changes on chromosome 11p15.5 as specific marker for embryonal rhabdomyosarcoma?

Rhabdomyosarcomas (RMS) constitute a heterogeneous spectrum of tumors with respect to clinical behavior and tumor morphology. The paternal uniparental disomy (pUPD) of 11p15.5 is a molecular change described mainly in embryonal RMS. In addition to LOH, UPD, the MLPA technique (ME030kit) also determines copy number variants and methylation of H19 and KCNQ1OT1 genes, which have not been systematically investigated in RMS. All 127 RMS tumors were divided by histology and PAX status into four groups, pleomorphic histology (n = 2); alveolar RMS PAX fusion-positive (PAX+; n = 39); embryonal RMS (n = 70) and fusion-negative RMS with alveolar pattern (PAX-RMS-AP; n = 16). The following changes were detected; negative (n = 21), pUPD (n = 75), gain of paternal allele (n = 9), loss of maternal allele (n = 9), hypermethylation of H19 (n = 6), hypomethylation of KCNQ1OT1 (n = 6), and deletion of CDKN1C (n = 1). We have shown no difference in the frequency of pUPD 11p15.5 in all groups. Thus, we have proven that changes in the 11p15.5 are not only specific to the embryonal RMS (ERMS), but are often also present in alveolar RMS (ARMS). We have found changes that have not yet been described in RMS. We also demonstrated new potential diagnostic markers for ERMS (paternal duplication and UPD of whole chromosome 11) and for ARMS PAX+ (hypomethylation KCNQ1OT1).

IGF2 deficiency promotes liver aging through mitochondrial dysfunction and upregulated CEBPB signaling in D-galactose-induced aging mice

BACKGROUND

Liver aging, marked by cellular senescence and low-grade inflammation, heightens susceptibility to chronic liver disease and worsens its prognosis. Insulin-like growth factor 2 (IGF2) has been implicated in numerous aging-related diseases. Nevertheless, its role and underlying molecular mechanisms in liver aging remain largely unexplored.

METHODS

The expression of IGF2 was examined in the liver of young (2-4 months), middle-aged (9-12 months), and old (24-26 months) C57BL/6 mice. In vivo, we used transgenic IGF2f/f; Alb-Cre mice and D-galactose-induced aging model to explore the role of IGF2 in liver aging. In vitro, we used specific short hairpin RNA against IGF2 to knock down IGF2 in AML12 cells. D-galactose and hydrogen peroxide treatment were used to induce AML12 cell senescence.

RESULTS

We observed a significant reduction of IGF2 levels in the livers of aged mice. Subsequently, we demonstrated that IGF2 deficiency promoted senescence phenotypes and senescence-associated secretory phenotypes (SASPs), both in vitro and in vivo aging models. Moreover, IGF2 deficiency impaired mitochondrial function, reducing mitochondrial respiratory capacity, mitochondrial membrane potential, and nicotinamide adenine dinucleotide (NAD)+/NADH ratio, increasing intracellular and mitochondrial reactive oxygen species levels, and disrupting mitochondrial membrane structure. Additionally, IGF2 deficiency markedly upregulated CCAAT/enhancer-binding protein beta (CEBPB). Notably, inhibiting CEBPB reversed the senescence phenotypes and reduced SASPs induced by IGF2 deficiency.

CONCLUSIONS

In summary, our findings strongly suggest that IGF2 deficiency promotes liver aging through mitochondrial dysfunction and upregulated CEBPB signaling. These results provide compelling evidence for considering IGF2 as a potential target for interventions aimed at slowing down the process of liver aging.

TMED10 mediates the trafficking of insulin-like growth factor 2 along the secretory pathway for myoblast differentiation

The insulin-like growth factor 2 (IGF2) plays critical roles in cell proliferation, migration, differentiation, and survival. Despite its importance, the molecular mechanisms mediating the trafficking of IGF2 along the secretory pathway remain unclear. Here, we utilized a Retention Using Selective Hook system to analyze molecular mechanisms that regulate the secretion of IGF2. We found that a type I transmembrane protein, TMED10, is essential for the secretion of IGF2 and for differentiation of mouse myoblast C2C12 cells. Further analyses indicate that the residues 112-140 in IGF2 are important for the secretion of IGF2 and these residues directly interact with the GOLD domain of TMED10. We then reconstituted the release of IGF2 into COPII vesicles. This assay suggests that TMED10 mediates the packaging of IGF2 into COPII vesicles to be efficiently delivered to the Golgi. Moreover, TMED10 also mediates ER export of TGN-localized cargo receptor, sortilin, which subsequently mediates TGN export of IGF2. These analyses indicate that TMED10 is critical for IGF2 secretion by directly regulating ER export and indirectly regulating TGN export of IGF2, providing insights into trafficking of IGF2 for myoblast differentiation.

Imprinted Dlk1-Gtl2 cluster miRNAs are potential epigenetic regulators of lamb fur quality

BACKGROUND

Tan and Hu sheep are well-known local breeds in China, producing lamb fur with unique ornamental and practical values highly appreciated by consumers worldwide. Fur quality is optimal at one month of age and gradually declines with time. Despite active research on its genetic mechanism using transcriptomic and whole genome bisulfite sequencing analysis, the main effective gene locus has not been found, and its regulatory mechanism is still unclear, which limits the breeding and improvement of fur traits.

RESULTS

Scapular skin samples from newborn (1-month old) and adult (24-month old) Tan sheep were utilized for small ribonucleic acid (RNA) sequencing Principal Component Analysis (PCA) showed that the newborn and adult groups were completely separated. Differential expression analysis of micro-RNAs (miRNAs) identified 32 up-regulated miRNAs and 48 down-regulated miRNAs in the newborn groups. All up-regulated miRNAs were located in the imprinted. Dlk1-Gtl2 locus on chromosome 18, whereas all down-regulated miRNAs were distributed across the sheep chromosomes, without a clear pattern of positional consistency. Further, by systematically analyzing the target genes and signaling pathways of all 32 up-regulated miRNAs, we found that the PI3K-AKT signaling pathway has the potential to be targeted and regulated by most of the miRNAs in the Dlk1-Gtl2 region. In addition, we also re-analyzed miRNA sequencing data from public databases on Hu lambs (full sibling Hu lambs with high- and low-quality fur characteristics). Again, it was found that most of the up-regulated miRNAs in lambs with high-quality fur were also located in the Dlk1-Gtl2 region, whereas this patter was not present for down-regulated miRNAs.

CONCLUSION

Sequencing of miRNAs in conjunction with public databases was employed to identify miRNAs within the imprinted Dlk1-Gtl2 region on chromosome 18, suggesting their potential roles as epigenetic regulators of fur traits. Small RNAs located at the Dlk1-Gtl2 locus were identified as having the potential to systematically regulate the PI3K-AKT signaling pathway, thereby indicating the relevance of the Dlk1-Gtl2/PI3K-AKT axis in the context of fur traits. Selection of parental specific expressed imprinted genes in the process of conserving and exploiting lamb fur traits should be emphasized.

A single-cell atlas of bovine skeletal muscle reveals mechanisms regulating intramuscular adipogenesis and fibrogenesis

BACKGROUND

Intramuscular fat (IMF) and intramuscular connective tissue (IMC) are often seen in human myopathies and are central to beef quality. The mechanisms regulating their accumulation remain poorly understood. Here, we explored the possibility of using beef cattle as a novel model for mechanistic studies of intramuscular adipogenesis and fibrogenesis.

METHODS

Skeletal muscle single-cell RNAseq was performed on three cattle breeds, including Wagyu (high IMF), Brahman (abundant IMC but scarce IMF), and Wagyu/Brahman cross. Sophisticated bioinformatics analyses, including clustering analysis, gene set enrichment analyses, gene regulatory network construction, RNA velocity, pseudotime analysis, and cell-cell communication analysis, were performed to elucidate heterogeneities and differentiation processes of individual cell types and differences between cattle breeds. Experiments were conducted to validate the function and specificity of identified key regulatory and marker genes. Integrated analysis with multiple published human and non-human primate datasets was performed to identify common mechanisms.

RESULTS

A total of 32 708 cells and 21 clusters were identified, including fibro/adipogenic progenitor (FAP) and other resident and infiltrating cell types. We identified an endomysial adipogenic FAP subpopulation enriched for COL4A1 and CFD (log2FC = 3.19 and 1.92, respectively; P < 0.0001) and a perimysial fibrogenic FAP subpopulation enriched for COL1A1 and POSTN (log2FC = 1.83 and 0.87, respectively; P < 0.0001), both of which were likely derived from an unspecified subpopulation. Further analysis revealed more progressed adipogenic programming of Wagyu FAPs and more advanced fibrogenic programming of Brahman FAPs. Mechanistically, NAB2 drives CFD expression, which in turn promotes adipogenesis. CFD expression in FAPs of young cattle before the onset of intramuscular adipogenesis was predictive of IMF contents in adulthood (R2  = 0.885, P < 0.01). Similar adipogenic and fibrogenic FAPs were identified in humans and monkeys. In aged humans with metabolic syndrome and progressed Duchenne muscular dystrophy (DMD) patients, increased CFD expression was observed (P < 0.05 and P < 0.0001, respectively), which was positively correlated with adipogenic marker expression, including ADIPOQ (R2  = 0.303, P < 0.01; and R2  = 0.348, P < 0.01, respectively). The specificity of Postn/POSTN as a fibrogenic FAP marker was validated using a lineage-tracing mouse line. POSTN expression was elevated in Brahman FAPs (P < 0.0001) and DMD patients (P < 0.01) but not in aged humans. Strong interactions between vascular cells and FAPs were also identified.

CONCLUSIONS

Our study demonstrates the feasibility of beef cattle as a model for studying IMF and IMC. We illustrate the FAP programming during intramuscular adipogenesis and fibrogenesis and reveal the reliability of CFD as a predictor and biomarker of IMF accumulation in cattle and humans.

The association between prenatal famine, DNA methylation and mental disorders: a systematic review and meta-analysis

BACKGROUND

Undernutrition in pregnant women is an unfavorable environmental condition that can affect the intrauterine development via epigenetic mechanisms and thus have long-lasting detrimental consequences for the mental health of the offspring later in life. One epigenetic mechanism that has been associated with mental disorders and undernutrition is alterations in DNA methylation. The effect of prenatal undernutrition on the mental health of adult offspring can be analyzed through quasi-experimental studies such as famine studies. The present systematic review and meta-analysis aims to analyze the association between prenatal famine exposure, DNA methylation, and mental disorders in adult offspring. We further investigate whether altered DNA methylation as a result of prenatal famine exposure is prospectively linked to mental disorders.

METHODS

We conducted a systematic search of the databases PubMed and PsycINFO to identify relevant records up to September 2022 on offspring whose mothers experienced famine directly before and/or during pregnancy, examining the impact of prenatal famine exposure on the offspring's DNA methylation and/or mental disorders or symptoms.

RESULTS

The systematic review showed that adults who were prenatally exposed to famine had an increased risk of schizophrenia and depression. Several studies reported an association between prenatal famine exposure and hyper- or hypomethylation of specific genes. The largest number of studies reported differences in DNA methylation of the IGF2 gene. Altered DNA methylation of the DUSP22 gene mediated the association between prenatal famine exposure and schizophrenia in adult offspring. Meta-analysis confirmed the increased risk of schizophrenia following prenatal famine exposure. For DNA methylation, meta-analysis was not suitable due to different microarrays/data processing approaches and/or unavailable data.

CONCLUSION

Prenatal famine exposure is associated with an increased risk of mental disorders and DNA methylation changes. The findings suggest that changes in DNA methylation of genes involved in neuronal, neuroendocrine, and immune processes may be a mechanism that promotes the development of mental disorders such as schizophrenia and depression in adult offspring. Such findings are crucial given that undernutrition has risen worldwide, increasing the risk of famine and thus also of negative effects on mental health.

Interference of a mammalian circRNA regulates lipid metabolism reprogramming by targeting miR-24-3p/Igf2/PI3K-AKT-mTOR and Igf2bp2/Ucp1 axis

White adipose tissue (WAT) is important for regulating the whole systemic energy homeostasis. Excessive WAT accumulation further contributes to the development of obesity and obesity-related illnesses. More detailed mechanisms for WAT lipid metabolism reprogramming, however, are still elusive. Here, we report the abnormally high expression of a circular RNA (circRNA) mmu_circ_0001874 in the WAT and liver of mice with obesity. mmu_circ_0001874 interference achieved using a specific adeno-associated virus infects target tissues, down-regulating lipid accumulation in the obesity mice WAT, and liver tissues. Mechanistically, miR-24-3p directly interacts with the lipid metabolism effect of mmu_circ_0001874 and participates in adipogenesis and lipid accumulation by targeting Igf2/PI3K-AKT-mTOR axis. Moreover, mmu_circ_0001874 binds to Igf2bp2 to interact with Ucp1, up-regulating Ucp1 translation and increasing thermogenesis to decrease lipid accumulation. In conclusion, our data highlight a physiological role for circRNA in lipid metabolism reprogramming and suggest mmu_circ_0001874/miR-24-3p/Igf2/PI3K-AKT-mTOR and mmu_circ_0001874/Igf2bp2/Ucp1 axis may represent a potential mechanism for controlling lipid accumulation in obesity.

IGF2 in memory, neurodevelopmental disorders, and neurodegenerative diseases

Insulin-like growth factor 2 (IGF2) emerged as a critical mechanism of synaptic plasticity and learning and memory. Deficits in IGF2 in the brain, serum, or cerebrospinal fluid (CSF) are associated with brain diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS). Increasing IGF2 levels enhances memory in healthy animals and reverses numerous symptoms in laboratory models of aging, neurodevelopmental disorders, and neurodegenerative diseases. These effects occur via the IGF2 receptor (IGF2R) - a receptor that is highly expressed in neurons and regulates protein trafficking, synthesis, and degradation. Here, I summarize the current knowledge regarding IGF2 expression and functions in the brain, particularly in memory, and propose a novel conceptual model for IGF2/IGF2R mechanisms of action in brain health and diseases.

Report on a Case with Moreno-Nishimura-Schmidt Overgrowth Syndrome: A Clinically Delineated Disease Yet of an Unknown Origin!

Introduction

Overgrowth syndromes are a heterogeneous group of genetic disorders characterized by excessive growth, often accompanied by additional clinical features, such as facial dysmorphism, hormonal imbalances, cognitive impairment, and increased risk for neoplasia. Moreno-Nishimura-Schmidt (M-N-S) overgrowth syndrome is a very rare overgrowth syndrome characterized by severe pre- and postnatal overgrowth, dysmorphic facial features, kyphoscoliosis, large hands and feet, inguinal hernia, and distinctive skeletal features. The clinical and radiological features of the disorder have been well delineated, yet its molecular pathogenesis remains unclear.

Case Presentation

We report on a Lebanese boy with M-N-S syndrome, whose clinical manifestations were compared with those of previously reported 5 affected individuals. Whole-exome sequencing combined with comparative genome hybridization analysis failed to delineate the molecular basis of the phenotype. However, epigenetic studies revealed a different methylation status of several CpG sites between him and healthy controls, with methyltransferase activity showing the most significant enrichment.

Conclusion

An additional case of M-N-S syndrome recapitulated the clinical and radiological manifestations described in the previous reports. The data in the epigenetic studies implicated that abnormal methylations might play an essential role in development of the disease phenotype. However, additional studies in a clinically homogeneous cohort of patients are crucial to confirm this hypothesis.

A combined computational and functional approach identifies IGF2BP2 as a driver of chemoresistance in a wide array of pre-clinical models of colorectal cancer

AIM

Chemoresistance is a major cause of treatment failure in colorectal cancer (CRC) therapy. In this study, the impact of the IGF2BP family of RNA-binding proteins on CRC chemoresistance was investigated using in silico, in vitro, and in vivo approaches.

METHODS

Gene expression data from a well-characterized cohort and publicly available cross-linking immunoprecipitation sequencing (CLIP-Seq) data were collected. Resistance to chemotherapeutics was assessed in patient-derived xenografts (PDXs) and patient-derived organoids (PDOs). Functional studies were performed in 2D and 3D cell culture models, including proliferation, spheroid growth, and mitochondrial respiration analyses.

RESULTS

We identified IGF2BP2 as the most abundant IGF2BP in primary and metastastatic CRC, correlating with tumor stage in patient samples and tumor growth in PDXs. IGF2BP2 expression in primary tumor tissue was significantly associated with resistance to selumetinib, gefitinib, and regorafenib in PDOs and to 5-fluorouracil and oxaliplatin in PDX in vivo. IGF2BP2 knockout (KO) HCT116 cells were more susceptible to regorafenib in 2D and to oxaliplatin, selumitinib, and nintedanib in 3D cell culture. Further, a bioinformatic analysis using CLIP data suggested stabilization of target transcripts in primary and metastatic tumors. Measurement of oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) revealed a decreased basal OCR and an increase in glycolytic ATP production rate in IGF2BP2 KO. In addition, real-time reverse transcriptase polymerase chain reaction (qPCR) analysis confirmed decreased expression of genes of the respiratory chain complex I, complex IV, and the outer mitochondrial membrane in IGF2BP2 KO cells.

CONCLUSIONS

IGF2BP2 correlates with CRC tumor growth in vivo and promotes chemoresistance by altering mitochondrial respiratory chain metabolism. As a druggable target, IGF2BP2 could be used in future CRC therapy to overcome CRC chemoresistance.

Glycosylation Analysis of Urinary Peptidome Highlights IGF2 Glycopeptides in Association with CKD

Chronic kidney disease (CKD) is prevalent in 10% of world’s adult population. The role of protein glycosylation in causal mechanisms of CKD progression is largely unknown. The aim of this study was to identify urinary O-linked glycopeptides in association to CKD for better characterization of CKD molecular manifestations. Urine samples from eight CKD and two healthy subjects were analyzed by CE-MS/MS and glycopeptides were identified by a specific software followed by manual inspection of the spectra. Distribution of the identified glycopeptides and their correlation with Age, eGFR and Albuminuria were evaluated in 3810 existing datasets. In total, 17 O-linked glycopeptides from 7 different proteins were identified, derived primarily from Insulin-like growth factor-II (IGF2). Glycosylation occurred at the surface exposed IGF2 Threonine 96 position. Three glycopeptides (DVStPPTVLPDNFPRYPVGKF, DVStPPTVLPDNFPRYPVG and DVStPPTVLPDNFPRYP) exhibited positive correlation with Age. The IGF2 glycopeptide (tPPTVLPDNFPRYP) showed a strong negative association with eGFR. These results suggest that with aging and deteriorating kidney function, alterations in IGF2 proteoforms take place, which may reflect changes in mature IGF2 protein. Further experiments corroborated this hypothesis as IGF2 increased plasma levels were observed in CKD patients. Protease predictions, considering also available transcriptomics data, suggest activation of cathepsin S with CKD, meriting further investigation.

Synergic Action of Insulin-like Growth Factor-2 and miRNA-483 in Pterygium Pathogenesis

Pterygium is a multifactorial disease in which UV-B is speculated to play a key role by inducing oxidative stress and phototoxic DNA damage. In search for candidate molecules that are useful for justifying the intense epithelial proliferation observed in pterygium, our attention has been focused on Insulin-like Growth Factor 2 (IGF-2), mainly detected in embryonic and fetal somatic tissues, which regulate metabolic and mitogenic functions. The binding between IGF-2 and its receptor Insulin-like Growth Factor 1 Receptor (IGF-1R) activates the PI3K-AKT pathway, which leads to the regulation of cell growth, differentiation, and the expression of specific genes. Since IGF2 is regulated by parental imprinting, in different human tumors, the IGF2 Loss of Imprinting (LOI) results in IGF-2- and IGF2-derived intronic miR-483 overexpression. Based on these activities, the purpose of this study was to investigate the overexpression of IGF-2, IGF-1R, and miR-483. Using an immunohistochemical approach, we demonstrated an intense colocalized epithelial overexpression of IGF-2 and IGF-1R in most pterygium samples (Fisher's exact test, p = 0.021). RT-qPCR gene expression analysis confirmed IGF2 upregulation and demonstrated miR-483 expression in pterygium compared to normal conjunctiva (253.2-fold and 12.47-fold, respectively). Therefore, IGF-2/IGF-1R co-expression could suggest their interplay through the two different paracrine/autocrine IGF-2 routes for signaling transfer, which would activate the PI3K/AKT signaling pathway. In this scenario, miR-483 gene family transcription might synergically reinforce IGF-2 oncogenic function through its boosting pro-proliferative and antiapoptotic activity.

Cell cycle control by the insulin-like growth factor signal: at the crossroad between cell growth and mitotic regulation

In proliferating cells and tissues a number of checkpoints (G1/S and G2/M) preceding cell division (M-phase) require the signal provided by growth factors present in serum. IGFs (I and II) have been demonstrated to constitute key intrinsic components of the peptidic active fraction of mammalian serum. In vivo genetic ablation studies have shown that the cellular signal triggered by the IGFs through their cellular receptors represents a non-replaceable requirement for cell growth and cell cycle progression. Retroactive and current evaluation of published literature sheds light on the intracellular circuitry activated by these factors providing us with a better picture of the pleiotropic mechanistic actions by which IGFs regulate both cell size and mitogenesis under developmental growth as well as in malignant proliferation. The present work aims to summarize the cumulative knowledge learned from the IGF ligands/receptors and their intracellular signaling transducers towards control of cell size and cell-cycle with particular focus to their actionable circuits in human cancer. Furthermore, we bring novel perspectives on key functional discriminants of the IGF growth-mitogenic pathway allowing re-evaluation on some of its signal components based upon established evidences.

Genetic ablation of the preptin-coding portion of Igf2 impairs pancreatic function in female mice

Preptin is a 34-amino acid peptide derived from the E-peptide of pro-insulin-like growth factor 2 and is co-secreted with insulin from β-cells. Little is understood about the effects of endogenous preptin on whole body glucose metabolism. We developed a novel mouse model in which the preptin portion of Igf2 was genetically ablated in all tissues, hereafter referred to as preptin knockout (KO), and tested the hypothesis that the removal of preptin will lead to a decreased insulin response to a metabolic challenge. Preptin KO and wild-type (WT) mice underwent weekly fasting blood glucose measurements, intraperitoneal insulin tolerance tests (ITT) at 9, 29, and 44 wk of age, and an oral glucose tolerance test (GTT) at 45 wk of age. Preptin KO mice of both sexes had similar Igf2 exon 2-3 mRNA expression in the liver and kidney compared with WT mice, but Igf2 exon 3-4 (preptin) expression was not detectable. Western blot analysis of neonatal serum indicated that processing of pro-IGF2 translated from the KO allele may be altered. Preptin KO mice had similar body weight, body composition, β-cell area, and fasted glucose concentrations compared with WT mice in both sexes up to 47 wk of age. Female KO mice had a diminished ability to mount an insulin response following glucose stimulation in vivo. This effect was absent in male KO mice. Although preptin is not essential for glucose homeostasis, when combined with previous in vitro and ex vivo findings, these data show that preptin positively impacts β-cell function.NEW & NOTEWORTHY This is the first study to describe a model in which the preptin-coding portion of the Igf2 gene has been genetically ablated in mice. The mice do not show reduced size at birth associated with Igf2 knockout suggesting that IGF2 functionality is maintained, yet we demonstrate a change in the processing of mature Igf2. Female knockout mice have diminished glucose-stimulated insulin secretion, whereas the insulin response in males is not different to wild type.

Non-coding RNAs: The link between maternal malnutrition and offspring metabolism

Early life nutrition is associated with the development and metabolism in later life, which is known as the Developmental Origin of Health and Diseases (DOHaD). Epigenetics have been proposed as an important explanation for this link between early life malnutrition and long-term diseases. Non-coding RNAs (ncRNAs) may play a role in this epigenetic programming. The expression of ncRNAs (such as long non-coding RNA H19, microRNA-122, and circular RNA-SETD2) was significantly altered in specific tissues of offspring exposed to maternal malnutrition. Changes in these downstream targets of ncRNAs lead to abnormal development and metabolism. This review aims to summarize the existing knowledge on ncRNAs linking the maternal nutrition condition and offspring metabolic diseases, such as obesity, type 2 diabetes (T2D) and non-alcoholic fatty liver disease (NAFLD).

Insulin-like Growth Factor-2 (IGF-2) in Fibrosis

The insulin family consists of insulin, insulin-like growth factor 1 (IGF-1), insulin-like growth factor 2 (IGF-2), their receptors (IR, IGF-1R and IGF-2R), and their binding proteins. All three ligands are involved in cell proliferation, apoptosis, protein synthesis and metabolism due to their homologous sequences and structural similarities. Insulin-like growth factor 2, a member of the insulin family, plays an important role in embryonic development, metabolic disorders, and tumorigenesis by combining with three receptors with different degrees of affinity. The main pathological feature of various fibrotic diseases is the excessive deposition of extracellular matrix (ECM) after tissue and organ damage, which eventually results in organic dysfunction because scar formation replaces tissue parenchyma. As a mitogenic factor, IGF-2 is overexpressed in many fibrotic diseases. It can promote the proliferation of fibroblasts significantly, as well as the production of ECM in a time- and dose-dependent manner. This review aims to describe the expression changes and fibrosis-promoting effects of IGF-2 in the skin, oral cavity, heart, lung, liver, and kidney fibrotic tissues.

Environmentally relevant concentrations of tris (1,3-dichloro-2-propyl) phosphate induce growth inhibition and oxidative stress in silver carp (Hypophthalmichthys molitrix) larvae

Tris (1,3-dichloro-2-propyl) phosphate (TDCIPP), widely applied as flame retardant into a variety of products, can be physically leached out to the aquatic environment. Measurable values of TDCIPP have been found in the environment and within biota. Many toxicological assessments have shown that TDCIPP could cause developmental toxicity and oxidative stress in fish. In this study, we focused on the effects of TDCIPP on the growth and oxidative stress of an important commercial fish species in China, silver carp (Hypophthalmichthys molitrix). Fish larvae was exposed to environmentally relevant concentrations (0.05, 0.5, 5 and 50 μg/L) of TDCIPP for 7, 14 and 28 days. Simultaneously, the transcription levels of genes associated with the growth hormone/insulin-like growth factor (GH/IGF) axis and the antioxidative enzymes were examined. The body length and body mass of silver carp larvae decreased significantly only under exposure to 5 and 50 μg/L of TDCIPP at 14 days compared with the control group, while differences on those paraments were observed at 0.05, 0.5, 5 and 50 μg/L when larvae were exposed for 28 days. The observation evidenced the time- and dose- dependent growth inhibitions caused by TDCIPP on silver carp larvae. Exposure to TDCIPP also decreased the contents of GH and IGF1 in fish attended by significant down-regulation of gh and igf1. Moreover, TDCIPP up-regulated the expression of cat, sod1 and gstt followed by an increase of the activities of catalase (CAT) and superoxide dismutase (SOD) and the levels of malondialdehyde (MDA) and glutathione (GSH), but the activities of glutathione peroxidase (GPX) were decreased. These results suggested that growth inhibition and oxidative stress co-occurred in silver carp larvae after exposure to environmentally relevant concentrations of TDCIPP accompanied by the abnormal expression of genes which associated with the GH/IGF axis and antioxidative enzymes.

Along the Bos taurus genome, uncover candidate imprinting control regions

BACKGROUND

In mammals, Imprinting Control Regions (ICRs) regulate a subset of genes in a parent-of-origin-specific manner. In both human and mouse, previous studies identified a set of CpG-rich motifs occurring as clusters in ICRs and germline Differentially Methylated Regions (gDMRs). These motifs consist of the ZFP57 binding site (ZFBS) overlapping a subset of MLL binding units known as MLL morphemes. MLL or MLL1 (Mixed Lineage Leukemia 1) is a relatively large multidomain protein that plays a central role in the regulation of transcription. The structures of both MLL1 and MLL2 include a domain (MT) that binds CpG-rich DNA and a conserved domain (SET) that methylates lysine 4 in histone H3 producing H3K4me3 marks in chromatin.

RESULTS

Since genomic imprinting impacts many developmental and key physiological processes, we followed a previous bioinformatics strategy to pinpoint ICR positions in the Bos taurus genome. Initial genome-wide analyses involved finding the positions of ZFP57 binding sites, and the CpG-rich motifs (ZFBS-morph overlaps) along cattle chromosomal DNA. By creating plots displaying the density of ZFBS-morph overlaps, we removed background noise and thus improved signal detection. With the density-plots, we could view the positions of peaks locating known and candidate ICRs in cattle DNA. Our evaluations revealed the correspondence of peaks in plots to reported known and inferred ICRs/DMRs in cattle. Beside peaks pinpointing such ICRs, the density-plots also revealed additional peaks. Since evaluations validated the robustness of our approach, we inferred that the additional peaks may correspond to candidate ICRs for imprinted gene expression.

CONCLUSION

Our bioinformatics strategy offers the first genome-wide approach for systematically localizing candidate ICRs. Furthermore, we have tailored our datasets for upload onto the UCSC genome browser so that researchers could find known and candidate ICRs with respect to a wide variety of annotations at all scales: from the positions of Single Nucleotide Polymorphisms (SNPs), to positions of genes, transcripts, and repeated DNA elements. Furthermore, the UCSC genome browser offers tools to produce enlarged views: to uncover the genes in the vicinity of candidate ICRs and thus discover potential imprinted genes for experimental validations.

IGF2: Development, Genetic and Epigenetic Abnormalities

In the 30 years since the first report of parental imprinting in insulin-like growth factor 2 (Igf2) knockout mouse models, we have learnt much about the structure of this protein, its role and regulation. Indeed, many animal and human studies involving innovative techniques have shed light on the complex regulation of IGF2 expression. The physiological roles of IGF-II have also been documented, revealing pleiotropic tissue-specific and developmental-stage-dependent action. Furthermore, in recent years, animal studies have highlighted important interspecies differences in IGF-II function, gene expression and regulation. The identification of human disorders due to impaired IGF2 gene expression has also helped to elucidate the major role of IGF-II in growth and in tumor proliferation. The Silver-Russell and Beckwith-Wiedemann syndromes are the most representative imprinted disorders, as they constitute both phenotypic and molecular mirrors of IGF2-linked abnormalities. The characterization of patients with either epigenetic or genetic defects altering IGF2 expression has confirmed the central role of IGF-II in human growth regulation, particularly before birth, and its effects on broader body functions, such as metabolism or tumor susceptibility. Given the long-term health impact of these rare disorders, it is important to understand the consequences of IGF2 defects in these patients.

Differential gene expression and hallmarks of stemness in epithelial cells of the developing rat epididymis

Epididymal development can be subdivided into three phases: undifferentiated, a period of differentiation, and expansion. The objectives of this study were (1) to assess gene expression profiles in epididymides, (2) predict signaling pathways, and (3) develop a novel 3D cell culture method to assess the regulation of epididymal development in vitro. Microarray analyses indicate that the largest changes in differential gene expression occurred between the 7- to 18-day period, in which 1452 genes were differentially expressed, while 671 differentially expressed genes were noted between days 18 and 28, and there were 560 differentially expressed genes between days 28 and 60. Multiple signaling pathways were predicted at different phases of development. Pathway associations indicated that in epididymides of 7- to 18-day old rats, there was a significant association of regulated genes implicated in stem cells, estrogens, thyroid hormones, and kidney development, while androgen- and estrogen-related pathways were enriched at other phases of development. Organoids were derived from CD49f + columnar cells from 7-day old rats, while no organoids developed from CD49f^- cells. Cells cultured in an epididymal basal cell organoid medium versus a commercial kidney differentiation medium supplemented with DHT revealed that irrespective of the culture medium, cells within differentiating organoids expressed p63, AQP9, and V-ATPase after 14 days of culture. The commercial kidney medium resulted in an increase in the number of organoids positive for p63, AQP9, and V-ATPase. Together, these data indicate that columnar cells represent an epididymal stem/progenitor cell population.

The Mechanism of Insulin-Like Growth Factor II mRNA-Binging Protein 3 Induce Decidualization and Maternal-Fetal Interface Cross Talk by TGF-β1 in Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is defined as the loss of two or more consecutive intrauterine pregnancies that are clinically established early in pregnancy. To date, the etiology and underlying mechanisms of RSA remain unclear. It is widely thought that the impairment of decidualization is inclined to induce subsequent pregnancy failure and leads to the dysregulation of extra-villous trophoblast invasion and proliferation through maternal–fetal cross talk. However, the mechanism of decidualization in RSA has yet to be understood. In our study, we demonstrate that decidual samples from RSA patients have significantly higher insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) and lower TGF-β1 levels compared to healthy controls. In addition, the overexpression of IGF2BP3 in human endometrial stromal cells (hESCs) can lead to the impairment of decidualization in vitro-induced model and the abnormal cell cycle regulation. Furthermore, TGF-β1 and MMP9 levels were greatly increased after decidualization, whereas IGF2BP3 overexpression inhibited endometrial mesenchymal decidualization by downregulating TGF-β1, impeding maternal–fetal interface cytokine cross talk, and limiting the ability of trophoblast invasion. In conclusion, our investigation first demonstrates that abnormal elevation of IGF2BP3 in the pregnant endometrium leads to the impairment of decidualization and abnormal trophoblast invasion, thereby predisposing individuals to RSA.

Epigenetics in Precision Nutrition

Precision nutrition is an emerging area of nutrition research, with primary focus on the individual variability in response to dietary and lifestyle factors, which are mainly determined by an individual’s intrinsic variations, such as those in genome, epigenome, and gut microbiome. The current research on precision nutrition is heavily focused on genome and gut microbiome, while epigenome (DNA methylation, non-coding RNAs, and histone modification) is largely neglected. The epigenome acts as the interface between the human genome and environmental stressors, including diets and lifestyle. Increasing evidence has suggested that epigenetic modifications, particularly DNA methylation, may determine the individual variability in metabolic health and response to dietary and lifestyle factors and, therefore, hold great promise in discovering novel markers for precision nutrition and potential targets for precision interventions. This review summarized recent studies on DNA methylation with obesity, diabetes, and cardiovascular disease, with more emphasis put in the relations of DNA methylation with nutrition and diet/lifestyle interventions. We also briefly reviewed other epigenetic events, such as non-coding RNAs, in relation to human health and nutrition, and discussed the potential role of epigenetics in the precision nutrition research.

Postnatal expression of IGF2 is the norm in amniote vertebrates

The insulin and insulin-like signalling (IIS) network plays an important role in mediating several life-history traits, including growth, reproduction and senescence. Although insulin-like growth factors (IGFs) 1 and 2 are both key hormones in the vertebrate IIS network, research on IGF2 in juveniles and adults has been largely neglected because early biomedical research on rodents found negligible IGF2 postnatal expression. Here, we challenge this assumption and ask to what degree IGF2 is expressed during postnatal life across amniotes by quantifying the relative gene expression of IGF1 and IGF2 using publicly available RNAseq data for 82 amniote species and quantitative polymerase chain reaction on liver cDNA at embryonic, juvenile and adult stages for two lizard, bird and mouse species. We found that (i) IGF2 is expressed postnatally across amniote species and life stages-often at a higher relative expression than IGF1, contradicting rodent models; (ii) the lack of rodent postnatal IGF2 expression is due to phylogenetic placement, not inbreeding or artificial selection; and (iii) adult IGF2 expression is sex-biased in some species. Our results demonstrate that IGF2 expression is typical for amniotes throughout life, suggesting that a comprehensive understanding of the mechanisms mediating variation in life-history traits will require studies that measure both IGFs.

The effects of temperature variation treatments on embryonic development: a mouse study

Since the development of ART, embryos have been cultured at 37 °C in an attempt to mimic the in vivo conditions and the average body temperature of an adult. However, a gradient of temperatures within the reproductive tract has been demonstrated in humans and several other mammalian species. Therefore, the aim of this study was to evaluate the effects of temperature variation treatments on mouse embryo quality through morphokinetic events, blastocyst morphology, the relative gene expression of Igf2, Bax, Bcl2 and Apaf1 and the metabolomics of individual culture media. Study groups consisted of 2 circadian treatments, T1 with embryos being cultured at 37 °C during the day and 35.5 °C during the night, T2 with 38.5 °C during the day and 37 °C during the night and a control group with constant 37 °C. Our main findings are that the lower-temperature group (T1) showed a consistent negative effect on mouse embryo development with “slow” cleaving embryos, poor-quality blastocysts, a higher expression of the apoptotic gene Apaf1, and a significantly different set of amino acids representing a more stressed metabolism. On the other hand, our higher-temperature group (T2) showed similar results to the control group, with no adverse effects on blastocyst viability.

Role of SVEP1 in Stroma-Dependent Hematopoiesis In vitro

Study of the microenvironment that supports hematopoietic stem cell (HSC) development in vivo is very difficult involving small numbers of interacting cells which are usually not well defined. While much is known about HSC niches located within the bone marrow in terms of contributing cell types and signalling molecules, very little is known about equivalent niches within spleen. Extramedullary hematopoiesis in spleen contributes myeloid cells important in the mobilisation of an immune response. As a result, it is important to develop in vitro models to identify the cells which constitute HSC niches in spleen and to identify the regulatory molecules supporting myeloid cell development. Studies described here document a model system to study the maintenance and differentiation of HSC by splenic stromal cells in vitro. The splenic stromal lines 5G3 and 3B5 differ in hematopoietic support capacity. SVEP1 and IGF2 are molecules of interest specifically expressed by 5G3 stroma. Gene knockdown technology using shRNA plasmids has been used to reduce gene expression in 5G3 and to determine specific effects on myeloid cell development following co-culture with overlaid hematopoietic progenitors in vitro. Knockdown of Svep1 gave specific inhibition of a dendritic cell (DC) population described previously in spleen (L-DC). Knockdown of Igf2 resulted in loss of production of a minor subset of conventional (c) DC. SVEP1 is now considered a marker of mesenchymal stromal cells with osteogenic differentiative capacity reflective of perivascular stromal cells. The power of this in vitro model is evidenced by the fact that it has been used to define SVEP1 as a specific adhesion molecule that regulates the hematopoietic process dependent on stromal niche interaction. The identification of stromal cells and molecules that contribute to the hematopoietic process in spleen, brings us closer to the realm of therapeutically regulating hematopoiesis in vivo, and to inhibiting niches which support cancer stem cells.

Longitudinal Human Milk miRNA Composition over the First 3 mo of Lactation in a Cohort of Healthy Mothers Delivering Term Infants

BACKGROUND

MicroRNAs (miRNAs) are small noncoding RNAs involved in posttranscriptional regulation. miRNAs can be secreted and found in many body fluids, and although they are particularly abundant in breastmilk, their functions remain elusive. Human milk (HM) miRNAs start to raise considerable interest, but a comprehensive understanding of the repertoire and expression profiles along lactation has not been well characterized.

OBJECTIVES

This study aimed to characterize the longitudinal profile of HM miRNA between the second week and third month postpartum.

METHODS

We used a new sensitive technology to measure HM miRNAs in a cohort of 44 French mothers [mean ± SD age: 31 ± 3.5; BMI (in kg/m2) 21.8 ± 2.3] who delivered at term and provided HM samples at 3 time points (17 ± 3 d, 60 ± 3 d, and 90 ± 3 d) during follow-up visits.

RESULTS

We detected 685 miRNAs, of which 35 showed a high and stable expression along the lactation period analyzed. We also described for the first time a set of 11 miRNAs with a dynamic expression profile. To gain insight into the potential functional relevance of this set of miRNAs, we selected miR-3126 and miR-3184 to treat undifferentiated Caco-2 human intestinal cells and then assessed differentially expressed genes and modulation of related biological pathways.

CONCLUSIONS

Overall, our study provides new insights into HM miRNA composition and, to our knowledge, the first description of its longitudinal dynamics in mothers who delivered at term. Our in vitro results obtained in undifferentiated Caco-2 human intestinal cells transfected with HM miRNAs also provide further support to the hypothesized mother-to-neonate signaling role of HM miRNAs. This trial was registered at clinicaltrials.gov as NCT01894893.

The Insulin-like Growth Factor Signalling Pathway in Cardiac Development and Regeneration

Insulin and Insulin-like growth factors (IGFs) perform key roles during embryonic development, regulating processes of cell proliferation and survival. The IGF signalling pathway comprises two IGFs (IGF1, IGF2), two IGF receptors (IGFR1, IGFR2), and six IGF binding proteins (IGFBPs) that regulate IGF transport and availability. The IGF signalling pathway is essential for cardiac development. IGF2 is the primary mitogen inducing ventricular cardiomyocyte proliferation and morphogenesis of the compact myocardial wall. Conditional deletion of the Igf1r and the insulin receptor (Insr) genes in the myocardium results in decreased cardiomyocyte proliferation and ventricular wall hypoplasia. The significance of the IGF signalling pathway during embryonic development has led to consider it as a candidate for adult cardiac repair and regeneration. In fact, paracrine IGF2 plays a key role in the transient regenerative ability of the newborn mouse heart. We aimed to review the current knowledge about the role played by the IGF signalling pathway during cardiac development and also the clinical potential of recapitulating this developmental axis in regeneration of the adult heart.

Chromatin Interaction Responds to Breast Muscle Development and Intramuscular Fat Deposition Between Chinese Indigenous Chicken and Fast-Growing Broiler

Skeletal muscle development and intramuscular fat (IMF) content, which positively contribute to meat production and quality, are regulated by precisely orchestrated processes. However, changes in three-dimensional chromatin structure and interaction, a newly emerged mediator of gene expression, during the skeletal muscle development and IMF deposition have remained unclear. In the present study, we analyzed the differences in muscle development and IMF content between one-day-old commercial Arbor Acres broiler (AA) and Chinese indigenous Lushi blue-shelled-egg chicken (LS) and performed Hi-C analysis on their breast muscles. Our results indicated that significantly higher IMF content, however remarkably lower muscle fiber diameter was detected in breast muscle of LS chicken compared to that of AA broiler. The chromatin intra-interaction was prior to inter-interaction in both AA and LS chicken, and chromatin inter-interaction was heavily focused on the small and gene-rich chromosomes. For genomic compartmentalization, no significant difference in the number of B type compartments was found, but AA had more A type compartments versus LS. The A/B compartment switching of AA versus LS showed more A to B switching than B to A switching. There were no significant differences in the average sizes and distributions of topologically associating domains (TAD). Additionally, approximately 50% of TAD boundaries were overlapping. The reforming and disappearing events of TAD boundaries were identified between AA and LS chicken breast muscles. Among these, the HMGCR gene was located in the TAD-boundary regions in AA broilers, but in TAD-interior regions in LS chickens, and the IGF2BP3 gene was located in the AA-unique TAD boundaries. Both HMGCR and IGF2BP3 genes exhibited increased mRNA expression in one-day-old AA broiler breast muscles. It was demonstrated that the IGF2BP3 and HMGCR genes regulated by TAD boundary sliding were potential biomarkers for chicken breast muscle development and IMF deposition. Our data not only provide a valuable understanding of higher-order chromatin dynamics during muscle development and lipid accumulation but also reveal new insights into the regulatory mechanisms of muscle development and IMF deposition in chicken.

Epigenetic changes occur in placentas of spontaneous and recurrent miscarriages

BACKGROUND

In contrast to genetic abnormalities which are well known to be responsible for around 50 % of human miscarriages, there is very few data about epigenetic alterations in spontaneous and recurrent miscarriages (SM, RM). The aim of this study was to analyze the histone modification marks H3K9ac and H3K4me3 in SM and RM.

METHODS

The abundance of histone modifications H3K4me3/H3K9ac was analyzed by western blot in frozen abortion material of SM and RM compared to a control group of legal pregnancy terminations. Further, to characterize placental tissue cells expressing H3K4me3/H3K9ac immunohistochemistry (IHC) and immunofluorescence was performed in 20 SM, 19 RM and 26 controls.

RESULTS

The western blot data showed a tendency to an overall reduction of H3K4me3/H3K9ac, in the placental tissue of particularly SM. Further we differentiated between syncytiotrophoblast, cytotrophoblast and decidual cells and found a significant decrease of H3K4me3 in SM in cytotrophoblast cells and syncytial stroma. In RM H3K4me3 was downregulated exclusively in the syncytiotrophoblast. H3K9ac was reduced in SM and RM in all evaluated compartments, except from the syncytiotrophoblast.

CONCLUSION

Our study showed an overall reduced histone modification of H3K4me3 and H3K9ac in the placental tissue of SM. Concerning RM, particularly the reduction of H3K9ac was detected in the placental tissue, indicating that RM group has distinct profile in epigenetic regulation. Whether these histone modifications are part of a possible pathophysiologic cascade during SM and RM or are merely indicating a defective placentation, cannot be concluded from this study.

Progress in understanding of relationship between diabetes and colorectal cancer

Several epidemiological studies have suggested that diabetes is closely associated with an increased risk of colorectal cancer and diabetes could be regarded as an independent risk factor for colorectal cancer. Potential pathophysiological mechanisms connecting diabetes and colorectal cancer include hyperglycemia, hyperinsulinemia, and insulin-like growth factor axis, chronic inflammation and oxidative stress, gastrointestinal motility disorder, and impaired immunological surveillance. Meanwhile, multiple studies have revealed that diabetes is negatively related to the prognosis of patients with colorectal cancer. This review mainly summarizes the current studies concerning the linkages between diabetes and colorectal cancer and the underlying pathophysiological mechanisms, so as to provide a theoretical basis for rational use of antidiabetic drugs and early diagnosis of diabetes-related colorectal cancer.

Hypothalamic Transcriptome Analysis Reveals the Crucial MicroRNAs and mRNAs Affecting Litter Size in Goats

The hypothalamus was the coordination center of the endocrine system, which played an important role in goat reproduction. However, the molecular mechanism of hypothalamus regulating litter size in goats was still poorly understood. This study aims to investigate the key functional genes associated with prolificacy by hypothalamus transcriptome analysis of goats. In this research, an integrated analysis of microRNAs (miRNAs)-mRNA was conducted using the hypothalamic tissue of Yunshang black goats in the follicular stage. A total of 72,220 transcripts were detected in RNA-seq. Besides, 1,836 differentially expressed genes (DEGs) were identified between high fecundity goats at the follicular phase (FP-HY) and low fecundity goats at the follicular phase (FP-LY). DEGs were significantly enriched in 71 Gene Ontology (GO) terms and 8 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The transcriptome data suggested that DEGs such as BMPR1B, FGFR1, IGF1 and CREB1 are directly or indirectly involved in many processes like hypothalamic gonadal hormone secretion. The miRNA-seq identified 1,837 miRNAs, of which 28 differentially expressed miRNAs (DEMs). These DEMs may affect the nerve cells survival of goat hypothalamic regulating the function of target genes and further affect the hormone secretion activities related to reproduction. They were enriched in prolactin signaling pathway, Jak-STAT signaling pathway and GnRH signaling pathway, as well as various metabolic pathways. Integrated analysis of DEMs and DEGs showed that 87 DEGs were potential target genes of 28 DEMs. After constructing a miRNA-mRNA pathway network, we identified several mRNA-miRNAs pairs by functional enrichment analysis, which was involved in hypothalamic nerve apoptosis. For example, NTRK3 was co-regulated by Novel-1187 and Novel-566, as well as another target PPP1R13L regulated by Novel-566. These results indicated that these key genes and miRNAs may play an important role in the development of goat hypothalamus and represent candidate targets for further research. This study provides a basis for further explanation of the basic molecular mechanism of hypothalamus, but also provides a new idea for a comprehensive understanding of prolificacy characteristics in Yunshang black goats.

Detection of a novel single nucleotide polymorphism in IGF2 gene with a negative impact on egg production and body weight in Japanese quail (Coturnix japonica)

Background

Insulin-like growth factor 2 (IGF2) is one of three hormones that share high structural similarity to insulin. It is involved in several insulin-like growth-regulating and mitogenic activities. This study was conducted to genotype the coding regions of the IGF2 gene in Japanese quail (Coturnix japonica) using PCR-SSCP-sequencing, and to assess the possible association of the polymorphism of these regions with the main egg production traits. A total of 240 female birds with an equal number of three Japanese quail populations (Brown or BR, Black or BL, and White or WT) were included in this study.

Results

All the genotyped regions exerted no heterogeneity in their sequences with one exception detected in the exon 2. In this locus, a novel single nucleotide polymorphism (SNP) was detected in which “A” was substituted with “G” at 81 position with a silent effect (p.F79=SNP) on IGF2 protein. Association analyses indicated a significant (P < 0.05) relation of this SNP with egg number (EN) and bird weight (BW) in the analyzed populations, in which the birds with AG genotype had lower EN and BW than those with AA genotype. The p.F79=SNP was largely detected in the WT line than the other two lines.

Conclusion

The detected p.F79=SNP has a highly negative effect on EN and BW in Japanese quail. Thus, the implementation of the variations of the IGF2 gene can be a useful marker in the marker-assisted selection of Japanese quail. This is the first report to describe IGF2 gene variations in Japanese quail, which strongly suggests raising the birds from the BR line with AA genotype when breeders desire to raise Japanese quail for large-scale egg production.

The Effect of Nano-Silica Gel on Biological Activity of Osteoblasts and Expression of Insulin-Like and Growth Factor-2

This study assessed the effect nano-silica gel material on bioactivity of osteoblasts and expression of IGF-2. Methods: Silica gel nanoparticles (Nanjing Kike Company) were divided according to their concentrations as follows; 0 μg/mL a control group with cells without nanoparticle treatment, 25 μg/mL as group 1, 50 μg/mL as group 2, and 100 μg/mL as group 3. The transmission electron microscope was used to measure morphology, while particle size analyzer was used to measure particle size, and potential analyzer measured Zeta potential, and MTT measured proliferation.Moreover, ALP kit was used to measure ALP activity, and Alizarin red staining measured formation of wild flower nodules, while RT-PCR was used to measure expression of IGF-2. Results: The shape of silica gel nanoparticles was spherical, with uniform particle size distribution, and particle size was between 50-800 nm. The average particle size was 383 nm, and Zeta potential was -12.3. The growth rate of control group and group 1 was relatively close (t = 0.95, P = 0.37), and growth rate of groups 2 and 3 was higher than control (group t2 = 5.63, P < 0.05, group t3 = 10.38, P < 0.05). The value-added rate for group 3 was higher than group 2 (t = 4.41, P < 0.05). Group 1 had higher activity than control group (t = 10.29, P < 0.05) and lower activity than group 3 (t = 9.85, P < 0.05) which had higher activity than group 2 (t = 4.16, P < 0.05). Groups 1, 2, and 3 induced the growth of osteoblasts, promoted calcium salt deposition, and produced red mineralized nodules where the cells converged. The formation of mineralized nodules obviously depended on concentration of silica nanoparticles. Group 1 had higher IGF-2 expression than control (t = 19.99, P < 0.05) and lower level than group 2 (t = 16.69, P < 0.05). Silica gel nanoparticles promoted MC3T3-E1 cell proliferation and differentiation. The mechanism of action may be that, silica gel nanoparticles accelerate the growth of ALP activity and osteoblast extracellular matrix mineralization by promoting the level of IGF-2. The production of chemical nodules accelerates the proliferation and differentiation of osteoblasts.

Epigenetic processes during preeclampsia and effects on fetal development and chronic health

Preeclampsia (PE), the leading cause of maternal and fetal morbidity and mortality, is associated with poor fetal growth, intrauterine growth restriction (IUGR) and low birth weight (LBW). Offspring of women who had PE are at increased risk for cardiovascular (CV) disease later in life. However, the exact etiology of PE is unknown. Moreover, there are no effective interventions to treat PE or alleviate IUGR and the developmental origins of chronic disease in the offspring. The placenta is critical to fetal growth and development. Epigenetic regulatory processes such as histone modifications, microRNAs and DNA methylation play an important role in placental development including contributions to the regulation of trophoblast invasion and remodeling of the spiral arteries. Epigenetic processes that lead to changes in placental gene expression in PE mediate downstream effects that contribute to the development of placenta dysfunction, a critical mediator in the onset of PE, impaired fetal growth and IUGR. Therefore, this review will focus on epigenetic processes that contribute to the pathogenesis of PE and IUGR. Understanding the epigenetic mechanisms that contribute to normal placental development and the initiating events in PE may lead to novel therapeutic targets in PE that improve fetal growth and mitigate increased CV risk in the offspring.

Evidence for and localization of proposed causative variants in cattle and pig genomes

BACKGROUND

This paper reviews the localization of published potential causative variants in contemporary pig and cattle reference genomes, and the evidence for their causality. In spite of the difficulties inherent to the identification of causative variants from genetic mapping and genome-wide association studies, researchers in animal genetics have proposed putative causative variants for several traits relevant to livestock breeding.

RESULTS

For this review, we read the literature that supports potential causative variants in 13 genes (ABCG2, DGAT1, GHR, IGF2, MC4R, MSTN, NR6A1, PHGK1, PRKAG3, PLRL, RYR1, SYNGR2 and VRTN) in cattle and pigs, and localized them in contemporary reference genomes. We review the evidence for their causality, by aiming to separate the evidence for the locus, the proposed causative gene and the proposed causative variant, and report the bioinformatic searches and tactics needed to localize the sequence variants in the cattle or pig genome.

CONCLUSIONS

Taken together, there is usually good evidence for the association at the locus level, some evidence for a specific causative gene at eight of the loci, and some experimental evidence for a specific causative variant at six of the loci. We recommend that researchers who report new potential causative variants use referenced coordinate systems, show local sequence context, and submit variants to repositories.

Expression of insulin-like growth factors depends on both mass and resource availability in female green anoles (Anolis carolinensis)

The insulin and insulin-like signaling (IIS) network is an important mediator of cellular growth and metabolism in animals, and is sensitive to environmental conditions such as temperature and resource availability. The two main hormones of the IIS network, insulin-like growth factor 1 (IGF1) and insulin-like growth factor 2 (IGF2), are present in all vertebrates, yet little is known regarding the responsiveness of IGF2 in particular to external stimuli in non-mammalian animals. We manipulated diet (low or high quantity of food: low and high diet group, respectively) in adult green anole (Anolis carolinensis) females to test the effect of energetic state on hepatic gene expression of IGF1 and IGF2. The absolute expression of IGF2 in female green anoles was 100 times higher than that of IGF1 regardless of diet treatment, and IGF1 and IGF2 expression interacted with post-treatment body mass and treatment, as did the expression of the purported housekeeping genes glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and eukaryotic elongation factor 2 (EEF2). The low diet group showed a negative relationship between body mass and gene expression for all genes, whereas the relationships between body mass and gene expression in the high diet group were either absent (in the case of IGF1) or positive (for all other genes). After accounting for total change in mass, the low diet group expressed IGF2, GAPDH and EEF2 at higher levels compared with individuals in the high diet group of a similar change in mass. These results illustrate that expression of IGF1 and IGF2, and of the housekeeping genes is affected by energe-tic status in reptiles.

Dietary fat intake during early pregnancy is associated with cord blood DNA methylation at IGF2 and H19 genes in newborns

Maternal fat intake during pregnancy affects fetal growth, but mechanisms underlying this relationship are unclear. We performed an exploratory study of the associations of fat consumption during pregnancy with cord blood DNA methylation of the insulin-like growth factor 2 (IGF2) and H19 genes. We used data from 96 uncomplicated full-term pregnancies of mothers of whom majority had normal body mass index (BMI) (66%) in Project Viva, a prospective pre-birth cohort. We assessed maternal diet with validated food frequency questionnaires during the first and second trimesters and measured DNA methylation in segments of the IGF2- and H19-differentially methylated regions (DMRs) by pyrosequencing DNA extracted from umbilical cord blood samples. Mean (SD) age was 32.8 (4.1) years and prepregnancy BMI was 24.0 (4.4) kg/m² . Mean DNA methylation was 56.3% (3.9%) for IGF2-DMR and 44.6% (1.9%) for H19-DMR. Greater first trimester intake of omega-6 polyunsaturated fat (effect per 1% of calories at the expense of carbohydrates) was associated with lower DNA methylation of IGF2-DMR (-1.2%; 95% confidence interval [CI]: -2.2%, -0.2%) and higher DNA methylation at H19-DMR (0.8%; 95% CI: 0.3%, 1.3%). On the other hand, greater first trimester intake of omega-3 polyunsaturated fat was associated with lower DNA methylation of the H19-DMR (-4.3%; 95% CI: -7.9%, -0.8%). We did not find significant associations of IGF2 and H19 methylation with IGF2 cord blood levels. Our findings suggest that early prenatal fat intake (omega-3, omega-6, and saturated fatty acids) may influence DNA methylation at the IGF2 and H19 locus, which could impact fetal development and long-term health.

Global transcriptome analysis of rat dorsal root ganglia to identify molecular pathways involved in incisional pain

To develop non-opioid therapies for postoperative incisional pain, we must understand its underlying molecular mechanisms. In this study, we assessed global gene expression changes in dorsal root ganglia neurons in a model of incisional pain to identify pertinent molecular pathways. Male, Sprague-Dawley rats underwent infiltration of 1% capsaicin or vehicle into the plantar hind paw (n = 6-9/group) 30 min before plantar incision. Twenty-four hours after incision or sham (control) surgery, lumbar L4-L6 dorsal root ganglias were collected from rats pretreated with vehicle or capsaicin. RNA was isolated and sequenced by next generation sequencing. The genes were then annotated to functional networks using a knowledge-based database, Ingenuity Pathway Analysis. In rats pretreated with vehicle, plantar incision caused robust hyperalgesia, up-regulated 36 genes and downregulated 90 genes in dorsal root ganglias one day after plantar incision. Capsaicin pretreatment attenuated pain behaviors, caused localized denervation of the dermis and epidermis, and prevented the incision-induced changes in 99 of 126 genes. The pathway analyses showed altered gene networks related to increased pro-inflammatory and decreased anti-inflammatory responses in dorsal root ganglias. Insulin-like growth factor signaling was identified as one of the major gene networks involved in the development of incisional pain. Expression of insulin-like growth factor -2 and IGFBP6 in dorsal root ganglia were independently validated with quantitative real-time polymerase chain reaction. We discovered a distinct subset of dorsal root ganglia genes and three key signaling pathways that are altered 24 h after plantar incision but are unchanged when incision was made after capsaicin infiltration in the skin. Further exploration of molecular mechanisms of incisional pain may yield novel therapeutic targets.