Biomedicine

Dr. R. Merkle is a specialist in the area of mechanosynthesis. Mechanosynthesis plays one of the leading roles in the classical molecular nanotechnology. Mechanosynthesis is defined as a chemical synthesis performed by mechanical systems and allowing to position reacting agents with high accuracy. R. Merkle’s research interests include obtaining of the programmable molecular compounds which can be used in the future for regeneration of cryopreserved tissues at the molecular and cellular levels.

In major neurodegenerative diseases, such as Alzheimer’s and Parkinson’s, the abnormal accumulation of one or more polypeptides within or around neurons is central to pathogenesis. R. Nixon’s research focuses on two aspects of neurobiology that govern the fate of normal and pathogenic proteins: the regulation of proteolytic processing and the control of protein export into axons and synapses. R. Nixon’s team have identified dysfunction of the endosomal-lysosomal system involving altered endocytosis and mistrafficking of proteases to endosomes, as the earlies known pathological response of neurons in Alzheimer’s disease. Cell modeling studies showed early endosomes to be major generators of the toxic beta-amyloid peptide and implicated dysfunction of endosomes in the mechanism of beta-amyloid accumulation in 'sporadic' Alzheimer’s. Consequences of endosomal-lysosomal and calpain system dysfunction on processing of Alzheimer-related proteins, receptor-mediated signal transduction, and neuronal cell death pathways were identified using genetic manipulations together with cell culture models. It was shown that calpain inhibitors improve memory and synaptic transmission in a mouse of Alzheimer disease.

The goal of research of F. Rosenfeldt’s team was to study the mechanisms of age-related decrease in stress tolerance of the heart and search for possible ways allowing to fight them. Specifically, the scientists investigated the possibility to use coenzyme Q (CoQ), which is a component of the mitochondrial respiratory chain, and other antioxidants. In experiments on rats, F. Rosenfeldt and his colleagues showed that the tolerance for aerobic stress caused by fast heart beating decreased in aging heart. However, CoQ provided specific protection in that situation. It was shown in clinical studies (on 100 patients whose average age was 68 years) that 2 week long CoQ intake preceding an operation on the heart enhanced mitochondrial effectiveness in the myocardium and the myocardial condition (in vitro and in vivo). Then in the pilot study on 14 patients, the action of various food supplements (α-lipoic acid, magnesium orotate and omega-3 fatty acid) taking as a part of the diet containing CoQ was studied. It was found that the patients who had taken such food supplements were faster discharged from the hospital, had a lower level of oxidative stress, and improved in quality of life. Thus, the authors concluded that the organism’s stress tolerance decreasing with aging could be restored by adding some substances into the diet.

The main scientific breakthroughs of prof. T. Okano’s team are associated with the modification of a temperature responsive polymer (poly(N-isopropylacrylamide)) as surfaces for tissue cultivation. Under standard culture conditions (37°С), these surfaces are hydrophobic, and cells adsorb and proliferate. When the temperature drops to 20°С, the polymer becomes hydrophilous. That allows to gather all cultured cells as intact sheets. In these sheets, all cells preserve their cytoskeleton and intercellular junctions intact. That allows to transfer them onto other surfaces and use them for bioengineered manipulations. This method is already successfully used in clinical practice for reconstruction of the eye surface, it also allows to solve the problem of donor tissue deficiency and allogenic transplant rejection. The regenerative medicine having concern with cornea diseases proposes just take a biopsy (2 square mm) of ectocorneal stem cells from the patient’s health eye in order to create a cell sheet for transplantation. Moreover, scientists have developed a technology suitable for bilateral corneal lesions. It uses an epithelial transplant obtained from the tunica mucosa of the patient’s mouth, that obviates the need for immunosuppression. In addition to two-dimensional cell sheets, three-dimensional structures have been created to use in heart tissue reconstruction. Sheets of cardiomyocytes layered one onto another showed spontaneous and simultaneous pulsation giving evidence that morphological links were established between cell sheets. This property allowed T. Okano to develop a cell sheet technology which will be used in tissue and organ regeneration. This technology completely excludes the use of any matrices and utilize autological cells only, without foreign components. The technology using sheets of cardiomyocytes may be useful in the heart model creation and in cardiovascular tissue restoration.

In Dr. M. Lokhandwala’s laboratory, the role of oxidative stress in cardiovascular diseases is investigated. The scientists have studied how physical activity (running on the special race track) affects markers of oxidative stress in old rats. The researchers have shown that physical activity increases the level of transcription factors which induce expression of proteins protecting from active forms of oxygen. Thus, the scientists concluded that physical activity reduces consequences of oxidative stress during aging.

Deposition of the β-amyloid peptide (Aβ) play key role in Alzheimer’s disease (AD) pathogenesis. So, the Alzheimer’s disease may be delayed if we lessen accumulation of the amyloid in the brain or hasten its excretion. Activity of neprilysin decreases at the early stages of Alzheimer’s disease and during age-related changes in the organism. M. Kindy investigated how introduction of neprilysin affected mice having Alzheimer’s disease at the early stages (before amyloid placque were formed). Then he evaluated how that impact affected deposition of the β-amyloid and how it affected allied pathogenetic changes. It was found, that after mice had been exposed to that impact, they showed improvement of spatial memory in Morris labyrinth. Those data show that replenishment of neprilysin in brain at early stages of Alzheimer’s disease is an effective method to prevent or ease Alzheimer’s disease pathogenesis. Neprilysin is the main brain enzyme responsible for destruction of the β-amyloid. Data obtained give evidence that neprilysin overexpression leads to the decrease of β-amyloid and related pathological processes.

The domain of prof. P. Langley’s interests includes following: 1. Artificial intelligence. 2. Creation of user-adapted interfaces. 3. Cognitive architecture. 4. Estimated models of human behavior. 5. Estimated models in biology and ecology. 6. Computational scientific discoveries. 7. Taught machines. 8. Standardization of methods helping solve and plan problems. Prof. P. Langley’s interest in aging problems is linked to his professional interests. The volume of information concerning aging is huge and extremely heterogeneous. Creation of computer models for studying the aging processes is one of prof. P. Langley’s scientific goals. Prof. P. Langley develops computer model of cell aging basing upon J. Furber’s scheme of the systems biology. The model of the lysosome has been created already.

Prof. L. Donehower’s main scientific theme is investigation on the role of tumor suppressors in cancer development and aging. The focus of L. Donehower’s researches is investigation of protective properties of p53 factor. In L. Donehower’s laboratory, mice having defective gene of p53 suppressor were created. Such mice have normal development, but since an early age, they have been demonstrating extremely high sensitivity to various forms of cancer. Similar phenotype is typical for «super» mice with additional copies of p53 or ARF genes, and for mice with genetically suppressed MDM2 activity. «Super» mouse with additional p53 and ARF genes has increased resistance to cancers and long life span. However, the situation is absolutely different when normal regulation of p53 gene is disturbed. Loss of p53 regulation was reached by removing N-end domain of the protein responsible for the interaction with MDM2. So, «m» mouse has a deletion 500 kilobase long that results in 26 genes following p53 removed and 6 exons of p53 gene removed as well. Another example is Р44tg mouse that expresses shortened form of p53 (p44). Both mouse models have increased stability and transcriptional activity of p53. That leads to increased cancer resistance but hastens aging of the animals due to depletion of the regenerative functions of their tissues. Similar phenotype is typical for mice with defective BRCA1 gene (maintenance factor of genome stability) or with defective ZMPTE24 protease. Such mice are exposed to permanent stress at the cellular level because of persisting DNA damages and chromosomal instability. At present, researches seeking for molecular mechanisms of influence of p53 on aging are conducted in L. Donehower’s laboratory. The basis for those researches are developed mouse models which have mutant p53. When p53 activity is heightened while basic regulation is kept, p53 protects from cancer but does not slow aging down. Completely lost p53 highly predisposes to cancer. A mouse with hyperexpression of p53 (р53 +/m) has much higher cancer resistance but shortened life span.

Scientists supposed two ways how this problem can be solved. The first way is following. New chimeric receptor is «suspended» upon T-cell surface. The receptor has external structure similar to that of antibodies, and it has a cytosolic domain transmitting a signal into the cell. That construction can retarget T-cells in vitro and force them to attack neoplasms. The second way is following. T-cells can be modified so they can express the natural heterodimer αβTCR detecting tumor cells. In the first clinical trial, T-cells with surface TCR specific to glycoprotein 100 (gp100) were created. A patient suffered from melanoma got an injection with those T-cells and IL-2 admixture. The aim of that method was to generate additional receptors through pairing transgenic TCR chains with natural ones. Scientists did not observe any toxic side effects. However, investigations show that expression level of gp100-specipic TCRs falls that can reduce TCR avidity and therefore minimize effector functions. Another important restriction of this method lies in the fact that every TCR is particular for the given peptide-MHC complex. Transplantation of T-lymphocytes is successfully used in various clinical cases deal with immunodeficiency and neoplasms. However, this treatment is less effective when a tumor has deficiency in the antigens. Prospective lines of the treatment based on the transplantation of modified immune cells is creation of T-cells insensitive to HIV. Preclinical trials show that such a cure is possible but its safety still should be established.

One of the important factors of cognitive-safe aging is integrity of the corpus callosum pathways; that integrity can be evaluated through diffusion tensor imaging (DTI). Higher integrity of the corpus callosum partly guarantees higher cognitive and intellectual abilities in old age. Simultaneously, genetic predisposition exists and it can be diagnosed. For example, it is known that inherited alleles of two functional polymorphisms of beta-2 adrenergic receptor (ADRB2) gene were linked to higher cognitive ability in 70-year-old patients. Moreover, allele of beta-2 adrenergic receptor (ADRB2) gene having single nucleotide polymorphism seemed to correlate with higher safety of the corpus callosum pathways and, consequently, with safer aging. Thus, unity of the information that characterize human genetic parameters, and data obtained during diagnostics of neural pathways can be used as preventive measures which ensure cognitive-safe aging.