Human cytomegalovirus manipulation of latently infected cells.

Primary infection with human cytomegalovirus (HCMV) results in the establishment of a lifelong infection of the host which is aided by the ability of HCMV to undergo a latent infection. One site of HCMV latency in vivo is in haematopoietic progenitor cells, resident in the bone marrow, with genome carriage and reactivation being restricted to the cells of the myeloid lineage. Until recently, HCMV latency has been considered to be relatively quiescent with the virus being maintained essentially as a "silent partner" until conditions are met that trigger reactivation. However, advances in techniques to study global changes in gene expression have begun to show that HCMV latency is a highly active process which involves expression of specific latency-associated viral gene products which orchestrate major changes in the latently infected cell. These changes are argued to help maintain latent infection and to modulate the cellular environment to the benefit of latent virus. In this review, we will discuss these new findings and how they impact not only on our understanding of the biology of HCMV latency but also how they could provide tantalising glimpses into mechanisms that could become targets for the clearance of latent HCMV

Block of death-receptor apoptosis protects mouse cytomegalovirus from macrophages and is a determinant of virulence in immunodeficient hosts.

The inhibition of death-receptor apoptosis is a conserved viral function. The murine cytomegalovirus (MCMV) gene M36 is a sequence and functional homologue of the human cytomegalovirus gene UL36, and it encodes an inhibitor of apoptosis that binds to caspase-8, blocks downstream signaling and thus contributes to viral fitness in macrophages and in vivo. Here we show a direct link between the inability of mutants lacking the M36 gene (ΔM36) to inhibit apoptosis, poor viral growth in macrophage cell cultures and viral in vivo fitness and virulence. ΔM36 grew poorly in RAG1 knockout mice and in RAG/IL-2-receptor common gamma chain double knockout mice (RAGγC(-/-)), but the depletion of macrophages in either mouse strain rescued the growth of ΔM36 to almost wild-type levels. This was consistent with the observation that activated macrophages were sufficient to impair ΔM36 growth in vitro. Namely, spiking fibroblast cell cultures with activated macrophages had a suppressive effect on ΔM36 growth, which could be reverted by z-VAD-fmk, a chemical apoptosis inhibitor. TNFα from activated macrophages synergized with IFNγ in target cells to inhibit ΔM36 growth. Hence, our data show that poor ΔM36 growth in macrophages does not reflect a defect in tropism, but rather a defect in the suppression of antiviral mediators secreted by macrophages. To the best of our knowledge, this shows for the first time an immune evasion mechanism that protects MCMV selectively from the antiviral activity of macrophages, and thus critically contributes to viral pathogenicity in the immunocompromised host devoid of the adaptive immune system

Перспективы применения сперматогониальных стволовых клеток при лечении мужской инфертильности

Spermatogonial stem cells, which are already present at birth in the testicles, are the progenitors of male gametes. These cells cannot produce mature sperm before puberty due to their dependence on hormonal stimuli. This feature of the reproductive system limits preservation of fertility only to males who can produce an ejaculate. Therefore, the use of cancer treatment which can lead to fertility loss has made sperm cryopreservation a standard practice. Prepubertal cancer boys – who are prescribed chemotherapy that is toxic to their reproductive system – are deprived of this fertility management procedure. This review focuses on the problem of obtaining and preserving spermatogonial stem cells for future transplantation to restore spermatogenesis. Development of these methods is becoming increasingly urgent due to higher survival rates in childhood cancer over the past decades thanks to improvements in diagnosis and effective treatment. Restoring and preserving fertility using spermatogonial stem cells may be the only option for such patients.Сперматогониальные стволовые клетки, которые существуют в семенниках с рождения, являются клетками-предшественниками мужских гамет. Эти клетки не способны продуцировать зрелые сперматозоиды до половой зрелости из-за их зависимости от гормональных стимулов. Эта особенность репродуктивной системы позволяет сохранять фертильность только мужчинам, которые способны производить эякулят. Поэтому при угрозе потери фертильности вследствие применения противоракового лечения стандартным является криоконсервация спермы. Этой возможности лишены неполовозрелые мальчики с онкологическими заболеваниями, которым назначают токсическую для их репродуктивной системы химиотерапию. В настоящем обзоре основное внимание уделяется проблеме получения и сохранения сперматогониальных стволовых клеток для будущей трансплантации с целью восстановления сперматогенеза. Разработка этих методов становится все более актуальной в связи с ростом за последние десятилетия выживаемости детей с онкологическими заболеваниями благодаря улучшению диагностики и эффективности лечения. Восстановление и сохранение фертильности с помощью сперматогониальных стволовых клеток может быть у таких пациентов безальтернативным вариантом

ПЕРСПЕКТИВЫ ПРИМЕНЕНИЯ ТКАНЕИНЖЕНЕРНЫХ КОНСТРУКЦИЙ ПОДЖЕЛУДОЧНОЙ ЖЕЛЕЗЫ В ЛЕЧЕНИИ САХАРНОГО ДИАБЕТА 1-го ТИПА

Allotransplantation of pancreatic islets remains the most effective method of treatment of diabetes mellitus type 1 being capable under combination of favorable conditions (suffi cient number of isolated islets, effective combination of immunosuppressive drugs) to reach the recipients’ insulin independence for several years. However, the overwhelming shortage of donor pancreas and limited post-transplantation islet survival do not allow increasing the number of such transplants and their effectiveness. This review presents a critical analysis of the work done by Russian and foreign authors onto creation of tissue-engineered pancreatic constructs that may lead to the resolution of the three main pancreatic islet transplantation issues: 1) lack of donor material; 2) necessity of immunosuppressive therapy; 3) limited survival and functional activity of the islet.Наиболее эффективным методом лечения сахарного диабета 1-го типа по-прежнему является аллотранс-плантация островков поджелудочной железы, которая при сочетании благоприятных условий (достаточное количество выделенных островков, удачная комбинация иммуносупрессивных препаратов) способна достичь инсулиннезависимости реципиентов на протяжении нескольких лет. Однако постоянный дефицит донорских поджелудочных желез и ограниченность выживания островков в организме реципиента не позволяют увеличить количество таких трансплантаций и повысить их эффективность. В настоящем обзоре дан критический анализ работ российских и зарубежных авторов по созданию тканеинженерных конструкций поджелудочной железы, направленных на решение трех главных проблем трансплантации островков поджелудочной железы: 1) дефицит донорского материала; 2) необходимость проведения иммуносупрессивной терапии; 3) непродолжительность выживания и функциональной активности пересаженных островков

High-throughput sequence analysis of variants of human cytomegalovirus strains Towne and AD169

The genomes of commonly used variants of human cytomegalovirus (HCMV) strains Towne and AD169 each contain a substantial mutation in which a region (UL/b′) at the right end of the long unique region has been replaced by an inverted duplication of a region from the left end of the genome. Using high-throughput technology, we have sequenced HCMV strain Towne (ATCC VR-977) and confirmed the presence of two variants, one exhibiting the replacement in UL/b′ and the other intact in this region. Both variants are mutated in genes RL13, UL1, UL40, UL130, US1 and US9. We have also sequenced a novel AD169 variant (varUC) that is intact in UL/b′ except for a small deletion that affects genes UL144, UL142, UL141 and UL140. Like other AD169 variants, varUC is mutated in genes RL5A, RL13, UL36 and UL131A. A subpopulation of varUC contains an additional deletion affecting genes IRS1, US1 and US2

Viral and Cell Cycle–Regulated Kinases in Cytomegalovirus-Induced Pseudomitosis and Replication

A process of pseudomitosis occurs during human cytomegalovirus infection that appears similar to cellular mitosis but involves the formation of multiple spindle poles, abnormal condensation, and mislocalization of chromosomal DNA. The relationship of this process to viral replication and cell cycle regulation during infection has been poorly understood. Pseudomitosis consistently peaks at late times of infection in all viral strains examined but at overall highest frequencies (30% to 35% of cells) using one common laboratory strain variant (AD169varATCC). Cyclin-dependent kinase 1 (Cdk1) plays a crucial role in pseudomitosis, mirroring its role in conventional mitosis. Dominant negative Cdk1 inhibits and wild-type Cdk1 stimulates this process; however, viral yields remain the same regardless of pseudomitosis levels. Broad inhibition of cell cycle−regulated kinases (Cdk1/Cdk2/Cdk5/Cdk9) with indirubin-3′-monoxime substantially decreases viral yields and synergizes with the viral UL97 kinase inhibitor, maribavir. Thus, Cdk1 is necessary and sufficient to drive pseudomitosis, whereas a combination of viral and cell cycle−regulated kinases is important during viral replication