Modification of Fecal Bacteria Counts and Blood Immune Cells in the Offspring of BALB/c and C57BL/6 Mice Obtained through Interstrain Mouse Embryo Transfer.

The reproducibility of results obtained with rodent models depends on the genetic purity of the strain and the stability of the environment. However, another potential factor is changes in the gut microbiota due to the transmission of mother's bacteria during embryo transfer. In this study, we demonstrate the transmission of the microbiota and immune cell blood phenotype to the offspring of 2 strains, C57BL/6JNskrc and BALB/cJNskrc, from surrogate dams of different genotypes. Interstrain embryo transfer resulted in a change in the number of Enterococcus spp. organisms, as shown by quantitative PCR analysis. The number of blood leukocytes was also affected, as estimated by flow cytometry. The number of blood leukocytes, including B cells and helper T cells, and the number of Enterococcus spp. organisms in male C57BL/6JNskrc offspring bornto BALB/cJNskrc surrogate dams became similar to those of male BALB/cJNskrc mice born to BALB/cJNskrc dams. Likewise, the same parameters of male BALB/cJNskrc mice born to C57BL/6JNskrc dams became similar to those of male C57BL/6JNskrc offspring. Researchers should be aware of the possible transmission of the dam's microbiota and immune cell phenotypes to the experimental strains when planning embryo transfer experiments, because these factors could affect the experimental outcomes or the reproducibility of experimental results.

Phenotypic variations in transferred progeny due to genotype of surrogate mother.

STUDY QUESTION: Does the genotype of the surrogate mother modulate the body composition and immunity of her offspring? SUMMARY ANSWER: C57BL/6J (B6) progenies carried by immunodeficient NOD SCID (NS) mothers had increased adaptive but decreased innate, immune responsiveness in comparison with the same genotype offspring carried by immunocompetent mothers, B6 and BALB/c (C); the B6 progenies carried by the same genotype mothers also showed higher body fat than the others. WHAT IS KNOWN ALREADY: Differences in the major histocompatibility complex (MHC) genes between mother and foetus is considered as an important factor in prenatal embryo development, whereas the impact of such dissimilarity on the phenotype of the mature progeny is unclear. STUDY DESIGN, SIZE, DURATION: Transplantation of two-cell mouse embryos into recipient females of the different MHC (H2) genotypes was used as an approach to simulate three variants of the immunogenic mother-foetus interaction: (i) bidirectional immunogenic dialogue between B6 (H2b haplotype) embryos and C (H2d haplotype) surrogate mother; (ii) one-way immunogenic interaction between B6 embryos and immunodeficient NS (H2g7 haplotype) surrogate mother and (iii) reduced immunogenetic dialogue between embryos and surrogate mother of the same H2b haplotype resulting in only a maternal response to HY antigens of male foetuses. Delivered by Caesarean section, pups were fostered by lactating B6 females and weighed after weaning (n = 171). Body mass and composition and innate and adaptive immunity were assessed in selected progeny groups at 9-11 weeks of age. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study was performed on the specific pathogen-free mouse, inbred strains C57BL/6J, NOD SCID and BALB/c. Plasma progesterone in pregnant females was measured by enzyme-linked immunosorbent assay (ELISA). Body composition was determined by magnetic resonance spectroscopy using a low-field NMR spectrometer (EchoMRI, USA). To assess peritoneal macrophage responses (innate immunity) to anthrax, lactate dehydrogenase (LDH) and interleukin-1 (IL-1ß) were measured in a culture medium 24 h after the addition of both anthrax-lethal factor and anthrax-protective antigen. To assess adaptive immunity, 9-10 males in experimental groups were infected with Helicobacter hepaticus. Faeces collected 2 and 4 weeks after infection was used for quantitative assessment of the H. hepaticus DNA by real-time polymerase chain reaction. IgA, interferon (IFN-γ), tumour necrosis factor (TNFα), interleukin-17 (IL-17) and interleukin-10 (IL-10) in colon tissue and IgG in serum were determined in samples collected 4 weeks after gavage with H. hepaticus using ELISA. For statistical analyses, ANCOVA, post hoc least significant difference (LSD) test, Student's t-test, Spearman rank correlations and χ2 test were performed. P-value <0.05 was considered as a statistically significant difference. MAIN RESULTS AND THE ROLE OF CHANCE: ANCOVA with litter size and age as covariates revealed significant effects of the surrogate mother genotype on body mass and percent of fat in their adult progeny (F2149 = 15.60, P < 0.001 and F2149 = 5.02, P = 0.007, respectively). Adult B6 mice carried by B6 surrogate mothers were characterized by a higher percentage of body fat in comparison with offspring that were carried by NS and C females. In comparison with the male offspring carried by the B6 and C mothers, male B6 progenies carried by immunodeficient NS mothers had a higher humoral immune response (serum IgG) against oral infection with H. hepaticus, but lower in vitro macrophage IL-1ß reaction to the anthrax. Four weeks after the infection of offspring, concentrations of serum IgG and colon IL-10 correlated positively with maternal progesterone on Day 4 after embryo transfer and negatively with DNA of H. hepaticus. One-way ANOVA confirmed a statistically significant impact of surrogate mother genotype on adaptive (IgG) and innate (IL-1ß) immunity (F2.26 = 26.39, P < 0.001 and F2.27 = 5.89, P = 0.008, respectively). LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: The main limitation of our study is the number of combinations of mother and foetus interactions, in particular, transfer of only one embryo genotype was used. Also, it is a descriptive study, which requires further analysis of the epigenetic mechanisms of the observed phenotypic effects of surrogate mother genotype. WIDER IMPLICATIONS OF THE FINDINGS: Our experimental data demonstrate that the transfer of inbred embryos to surrogate mothers of the different genotypes is a prospective experimental model for the study of epigenetic effects of the immunogenetic interactions between mother and foetus. The experimental approach tested in our study will be in demand for the development of criteria for choosing surrogate mothers. In particular, immunocompetence of the surrogate mother along with genetic distance of her MHC alleles to the transferred embryos have a significant impact on offspring development. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Russian FPI (6/099/2017), budget projects (0324-2016-0002 and 0324-2018-0016) and implemented using the equipment of the Centre for Genetic Resources of Laboratory Animals at ICG SB RAS, supported by the Ministry of Education and Science of Russia (Unique project identifier RFMEFI62117X0015). The authors report no conflicts of interest.

Nanoparticles Associate with Intrinsically Disordered RNA-Binding Proteins.

Nanoparticles are capable of penetrating cells, but little is known about the way they interact with intracellular proteome. Here we show that inorganic nanoparticles associate with low-complexity, intrinsically disordered proteins from HeLa cytosolic protein extracts in nondenaturing in vitro nanoparticle pull-down assays. Intrinsic protein disorder associates with structural mobility, suggesting that side-chain flexibility plays an important role in the driving of a protein to nanoparticle absorption. Disordered protein domains are often found in a diverse group of RNA-binding proteins. Consequently, the nanoparticle-associated proteomes were enriched in subunits of RNA-processing protein complexes. In turn, this indicates that within a cell, nanoparticles might interfere with protein synthesis triggering a range of cellular responses.

Modulation of embryonic development due to mating with immunised males.

The modification of pre- and postnatal development conferred by immunogenic stimulation of mothers provides a population-level adaptation mechanism for non-genetic transfer of maternal experiences to progeny. However little is known about the transmission of paternal immune experiences to offspring. Here, we show that immune priming of males 3-9 days before mating affects the growth and humoral environment of developing embryos of outbred (ICR) and inbred (C57BL and BALB/c) mice. Antigenic stimulation of fathers caused a significant increase in embryonic bodyweight as measured on Day 16 of pregnancy and altered other gestation parameters, such as feto-placental ratio. Pregnant females mated with immunised males were also characterised by changes in humoral conditions as shown by measurements of blood and amniotic progesterone, testosterone and granulocyte-macrophage colony-stimulating factor (GM-CSF) cytokine concentrations. These results emphasise the role of paternal effects of immune priming on the in utero environment and fetal growth.

Comparison of behavioral and biochemical deficits in rats with hereditary defined or D-galactose-induced accelerated senescence: evaluating the protective effects of diosgenin.

One of the important factors in aging is oxidative stress and aging-related disturbances are believed be ameliorated by antioxidants. Diosgenin is a bio-active ingredient of dioscorea that is widely used in Chinese medicine, shows anti-oxidant activity and improves some aging-related deficits in senescent and menopausal animals. We compared alterations in behavior, biochemical parameters (plasma levels of the uric acid, creatinine, calcium, phosphate, total cholesterol, low-density lipoprotein cholesterol and triglycerides, and the plasma activity of aminotransferases AST and ALT), and sperm motility in two models of accelerated senescence (d-galactose-induced (150 mg/kg/day, i.p., 57 days) aging in Wistar rats vs. genetically defined in OXYS rats) and examined the protective effects of diosgenin (10 or 50mg/kg/day, p.o., 57 days). Both models had augmented levels of ALT activity indicating hepatopathology. Compared to d-galactose-treated animals, OXYS rats demonstrated profound biochemical alterations (hypocalcemia, hypophosphatemia, and hypocholesterolemia) and behavioral deficits (impaired object recognition, decreased sexual motivation and locomotor activity, retarded learning) that confirmed the difference in the mechanisms of accelerated senescence in these models. We first showed diminished sperm motility in males of both models of accelerated senescence studied. Chronic diosgenin treatment failed to improve biochemical and behavioral disturbances and had some undesirable side effects on body weight and working memory in OXYS rats. However, diosgenin restored moderately decreased sperm motility in d-galactose-treated Wistar males and might be recommended for treatment of mild age-related reproductive dysfunctions.

IL-1ß-independent activation of lung immunity in male mice by female odor.

In previous studies, we showed that long-term perception of female odor increases flu virus resistance in male mice. To expand on this finding, we examined the ability of female chemical cues to rapidly induce leukocyte mobilization into male lung tissue as a critical condition of signal-derived respiratory infection risk reduction, which is usually associated with sniffing scent marks. Here, we compared the immune and endocrine effects of female chemical cues and lipopolysaccharide (LPS) as common triggers of innate immunity. The number of leukocytes in the lung tissue, concentrations of IL-1ß in lung and hypothalamus, and plasma corticosterone and testosterone levels were assessed in ICR male mice 2h after the intranasal application of female urine, LPS or urine and LPS. Both stimuli induced leukocyte mobilization but, in contrast to LPS, female urine alone did not stimulate increased IL-1ß levels in lung and hypothalamus. Plasma corticosterone increased and plasma testosterone decreased in response to LPS, whereas the concentrations of these hormones did not change in response to female chemical cues. Thus, the present study gives additional evidence for an anticipatory adaptation of male mice to potential breeding risks. Appreciable mobilization of leukocytes to the lungs requires less than 2h and develops through an IL-1ß-independent pathway.

Antigen-induced changes in odor attractiveness and reproductive output in male mice.

Modulation of social signals by antigen-induced immunoenhancement is a significant component of behavioral and reproductive adaptations of a host population to parasitic pressure. To investigate this concept, we studied odor attractiveness and reproductive output of ICR male mice treated with keyhole limpet hemocyanin (KLH) as an antigenic stimulus. We collected urine samples for olfactory preference tests (control vs. KLH administration) on different days following treatment. We found that the differences in odor attractiveness between control and immunized males, which were observed on the 3rd day, disappeared soon afterwards. Odor attractiveness of male mice positively correlated with their immunoresponsiveness, which was assessed by the sum of anti-KLH IgG1 and anti-KLH IgG2a titers. According to the hypothesis of terminal investment, antigen-treated males had higher reproductive output in comparison with control males and produced more progeny as a result.

Female scent mobilizes leukocytes to airways in BALB/c male mice.

The scent of receptive females as a signal to reproduction stimulates male mice to olfactory search of a potential breeding partner. This searching behavior is coupled with infection risk due to bacterial contamination of the fecal and urine scent marks. We hypothesized that sniffing of female soiled bedding induced the migration of immuno-competent cells into airways as a possible adaptation to breeding-related infection. Using bronchoalveolar lavage in a study on mice, we found the number of leukocytes to be significantly higher in male mice that were provided new portions of soiled bedding daily from female cages, in comparison with male mice that were kept in isolation from female scent. The number of leukocytes in blood was equal in both groups. However, monocytes were fewer in number in male mice exposed to female scent than in male mice isolated from female mice. Scent-induced migration of leukocytes was accompanied by typical behavioral (increased sniffing activity and aggressiveness) and morphological (increase preputial glands and seminal vesicles) responses to olfactory sexual stimulus.