Identification of the novel HLA-DQA1*05:107 allele

Full length sequence characterisation of the novel HLA-DQA1*05:107 allele from whole genome sequencing data.

Transferability of the PRS estimates for height and BMI obtained from the European ethnic groups to the Western Russian populations

Genetic data plays an increasingly important role in modern medicine. Decrease in the cost of sequencing with subsequent increase in imputation accuracy, and the accumulation of large amounts of high-quality genetic data enable the creation of polygenic risk scores (PRSs) to perform genotype-phenotype associations. The accuracy of phenotype prediction primarily depends on the overall trait heritability, Genome-wide association studies cohort size, and the similarity of genetic background between the base and the target cohort. Here we utilized 8,664 high coverage genomic samples collected across Russia by "Evogen", a Russian biomedical company, to evaluate the predictive power of PRSs based on summary statistics established on cohorts of European ancestry for basic phenotypic traits, namely height and BMI. We have demonstrated that the PRSs calculated for selected traits in three distinct Russian populations, recapitulate the predictive power from the original studies. This is evidence that GWAS summary statistics calculated on cohorts of European ancestry are transferable onto at least some ethnic groups in Russia.

[The prospects for the creation of the National Center for Personalized Medicine of Endocrine Diseases]

ФГБУ «НМИЦ эндокринологии» Минздрава России (НМИЦ эндокринологии) получил право реализовать программу развития Научного Центра Мирового Уровня «Национальный Центр Персонализированной медицины эндокринных заболеваний» (НЦПМЭЗ). Задачей НЦПМЭЗ станет не только создание системы персонализированного лечения, но и подготовка новых кадров для медицины. Фундаментальные исследования, проводимые на базе уже существующих институтов и лабораторий НМИЦ эндокринологии, будут расширены за счет создаваемых de novo лабораторий НЦПМЭЗ в соответствии с одобренным проектом.  Данная публикация знакомит читателя с наиболее значимыми лабораториями, которые планируется создать в НЦПМЭЗ: лабораторией общей, молекулярной и популяционной генетики, биоинформатики, фармакогеномики, микробиоты, редактирования генома, математических и цифровых технологий, неинвазивных технологий диагностики эндокринопатий, клеточных технологий, искусственного интеллекта и принципиально новой, не имеющей аналогов, лабораторией метаболической визуализации и радиотераностики.  Авторы надеются, что читатели одного из основных журналов для эндокринологов нашей страны примут активное участие в осуществлении планов НМИЦ эндокринологии, поскольку как у молодых, так и у опытных талантливых исследователей появится шанс стать частью команды Центра. Для выполнения амбициозных задач необходимо кардинально изменить мировоззрение врача в стране, разработать новую систему обучения за счет увеличения числа специалистов по медицинской генетике, транскриптомике, биостатистике и биоинформатике, работающих на стыке экспериментальной и клинической эндокринологии, что обеспечит транзит инновационных технологий в клиническую практику. Созданные лаборатории Научного Центра Мирового Уровня станут местом будничной работы нового поколения врачей, владеющих не только основами клинической работы, но и навыками фундаментальных исследований, что позволит им значительно улучшить методы прогнозирования, диагностики и лечения.

95 Obtaining birds with chimeric gonads using invitro lentiviral transduction of primordial germ cells

Avian primordial germ cells (PGCs) have unique migration capacity towards the gonads via the bloodstream. Therefore, PGCs invitro genome modification is a dominant approach for poultry genetic modification. The aim of this study was to improve cultivation conditions of PGCs in terms of proliferation activity and further analyse their migration abilities. We isolated PGCs from whole blood cells collected from the embryonic dorsal aorta (Hamburger-Hamilton (HH) stage 14-17) and cultured them without feeder cells in customized avian knockout Dulbecco's modified Eagle's medium basal medium supplemented with fibroblast growth factor 2, Activin A and B-27 supplement containing insulin. We analysed the number of cells during the month of culture. Proliferation of PGCs increased in the first 7d of culture when both BMP4 and Activin A growth factors were added to the medium (four out of seven samples). Kinetic of stemness and PGC-marker genes (Nanog, PouV, DAZL) were similar to expression in mature gonadal PGCs (gPGCs). Expression levels of marker genes were significantly greater in the freshly isolated PGCs compared to the gPGCs and decreased during cultivation. In order to confirm the migration activity of the cultivated PGCs, cells were labelled with lentivirus (ZsGreen) and injected into the embryo blood stream (HH 14-17). Gonads from the recipient embryos were retrieved (HH 20-26) and analysed. Due to the low level of fluorescence in mature cells, the presence of transgenic PGC in the gonads was detected by ZsGreen-specific quantitative PCR. We confirmed that the cultured cells maintained migration activity, and efficient engraftment was detected in 75% of embryos.

200 Optimization of Individual Stages of Chicken Transgenesis to Increase Efficiency

Primordial germ cells (PGC) are the precursors of male and female progenitor cells. The cells are considered a valuable genetic material for the production of transgenic poultry. This technology includes isolation of the PGC from chick donor embryos, transformation of the cells, and injection into the dorsal aorta of recipient embryos. After injection, the PGC are involved in the process of embryo development and differentiate into male or female sex cells. The aim of the research was to optimize the individual stages of this technology to increase the efficiency of transgenesis. The PGC were extracted from embryo gonads at stage 26 to 27 (H&H) using the trypsinization process. The trypsin concentration and incubation time were determined experimentally. Treatment of chick embryos with a 0.05% trypsin solution for 5 min was optimal for obtaining culture of embryonic cells. Separation of the PGC from other types of embryonic cells was based on a differential adhesive capacity. The maximum homogeneity of the cell population for further cultivation was established by transfer (twice) of the supernatant containing unattached cells after 1 h of cultivation in a new culture dish. The cell population is represented mainly by the PGC (81 ± 4%). Additional purification of the PGC from other cell types using magnetic-activated cell sorting (MACS) increased the proportion of these cells up to 93 ± 2%. The lentiviral transduction (pHAGE vector, ZsGreen under CMV promotor) was used to transform the resulting culture of the PGC. The efficiency of infection of PGC with lentiviral particles (TU/mL = 2.5 × 108) was 70 ± 3%. The transformed cells were injected into the dorsal aorta of recipient embryos on Day 2.5 (n = 80). Before injecting donor PGC, recipient embryos were treated with busulfan to remove the endogenous PGC. The optimal dose of busulfan was selected experimentally. A series of experiments introducing busulfan in concentrations from 50 to 250 μg into chick embryos at 24 h of incubation showed that the optimal dose was 100 μg/embryo. The efficacy of colonization of gonads with donor PGC was assessed on Day-10 embryos (n = 32) and 4-week-old hatched chickens (n = 12). Cells from gonads were studied using fluorescence microscopy, fluorescence-activated cell sorting (FACS) and qPCR. The presence of fluorescent cells in the gonads of recipients was established in both embryos and hatched chickens. The relative number of the recombinant DNA copies and the relative level of expression were confirmed by qPCR. The FACS analysis of sex cells isolated from gonads of recipients showed that the percentage of transformed germ cells reached 55.8% in females (n = 5) and 31.9% in males (n = 7). Thus, the effectiveness of poultry transgenesis can be enhanced by preparation of donor PGC for injection into embryo recipients and elimination of endogenous PGC in recipients. Both the purification of PGC from other cell types based on adhesive capacity as well as treatment of embryo recipients at 24 h incubation with busulfan (100 μg/embryo) increased the effectiveness of transgenesis. Study supported by the RSF within project No. 16-16-10059.

111 Inhibition of Avian Influenza Virus by Blocking Specific Sialyltransferases

It is known that avian influenza penetrates into the host cell by binding with sialic acids, the terminal residues of oligosaccharides. Avian influenza A virus preferably recognises α(2,3)-linked sialic acid residues as a receptor for penetration whereas human influenza A virus preferably binds with α(2,6)-linked sialic acids. Prevention of transfer of sialic acids to sugar bond or removal of it could be a defensive strategy against viral infection. There are 6 known sialyltransferases (ST3Gal1-6) that transfer α(2,3)-linked sialic acid residues to sugar branches. Most avian influenza virus isolates bind strongly to a sugar chain containing Neu5Aca(2,3) residues. In our study, we have shown that knockout of sialyltransferases leads to inhibition of viral infection. To find the expressed sialyltransferases in respiratory and digestive tracts, we used RT-qPCR. Tissue samples were taken from 3 chickens of Haisex white cross. Expression of mRNA was measured by RT-qPCR in 3 repeats and serial dilutions. Data analysis was carried out using the 2−ΔΔCt method. The amount of total RNA was normalised using GAPDH mRNA. For CRISPR/Cas9 targeting sialyltransferases, 3 guide RNAs for each gene were designed. We confirmed knockout (KO) of ST3GAL1 and ST3GAL6 by T7E assay. To estimate sialylation level on the cell surface, we performed a lectin-binding assay. For the assay, cells were incubated with fluorescein isothiocyanate (FITC)-labelled Maackia amurensis lectins and then subjected to flow-cytometry analysis to quantify the percentage of α(2,3)-sialylated cells in DF1 knockout (KO) v. DF1 wild type (wt) cell line. To estimate resistance to viral infection, a hemagglutinin binding assay was done, using fluorescein isothiocyanate (FITC)-labelled HA1 from H5N1 (A/Vietnam/1203/2004). To quantify the percentage of agglutinated HA1 molecules, DF1 KO and DF1 wt cells were analysed by flow cytometry. We found that mainly ST3GAL4 and ST3GAL5 are expressed in the chicken intestine (3-fold and 20-fold less compared with GAPDH level, respectively; other STs were not detected), and mainly ST3GAL1 and ST3GAL6 are expressed in the chicken respiratory tract (5-fold and 1.2-fold more compared with GAPDH level respectively; other STs were not detected). The expression profile of α(2,3)-sialyltransferases in the DF1 chicken cell line showed the noticeable expression of ST3GAL1 and ST3GAL6 compared with others as has been shown for the respiratory tract (500- and 1000-fold less compared with GAPDH respectively; other STs were not detected). In this study, we adopted the CRISPR/Cas9 system to knock out ST3GAL1 and ST3GAL6 genes in the chicken DF1 cell line. We confirmed that knockout of the genes leads to extinction of α(2,3)-sialic residues from the cell surface (7% v. 100% for DF1 KO v. DF1 wt cell line). Finally, we showed that knockout of sialyltransferases in the DF1 cells increases resistance against influenza A infection (16% v. 100% for DF1 KO v. DF1 wt cell line). Thus, creation of transgenic poultry with tissue-specific knockout of the α(2,3) sialyltransferases might protect domestic birds against influenza virus and block possible transfer of avian flu to human population.