Pathomorphological changes of capillaries in the cerebral cortex in type 2 diabetes mellitus

The aim of the study was to determine microscopic, immunohistochemical, electron microscopic, morphometric parameters of capillaries in the cerebral cortex in deceased patients with type 2 diabetes mellitus (DM) in comparison with the conditional control group and the group of deceased patients with dyscirculatory ischemic encephalopathy. Materials and methods. Microscopic, immunohistochemical, electron microscopic and morphometric studies of the cerebral cortex capillaries were performed in 3 groups: group I – 20 deceased patients with type 2 DM, group II conditional control (CC) – 20 deceased patients without clinical morphological signs of DM and cerebrovascular pathology, group III – 20 patients with dyscirculatory ischemic encephalopathy (DIEP). Results. It was found that in type 2 DM, the capillaries in the cerebral cortex lose pericytes due to their apoptosis: the number of pericytes in the cortical capillaries in type 2 DM was statistically significantly lower by 57.14 % compared to CC group and 50.00 % lower compared to DIEP group, the level of caspase-3 expression in the cortical microvessels in type 2 DM was significantly higher by 230.85 % compared with CC group and 81.67 % higher than in DIEP group. According to electron microscopy in type 2 DM, apoptosis of pericytes and single endothelial cells in the cerebral cortex capillaries was determined as well as significant expansion of basement membranes with the accumulation of electron-dense amorphous material and collagen fibrils. According to the results of morphometry, the outer diameter of the cortical capillaries in type 2 DM group was 4.90 % significantly larger, the inner diameter was 9.78 % smaller and the walls were 66.62 % thicker (compared with CC group) due to the accumulation of PAS-positive substances of blood serum and fibrosis, confirmed by 22.96 % greater area of type IV collagen expression in the microvessel walls. Conclusions. The pathomorphological changes of microvessels identified in deceased patients with type 2 diabetes mellitus are signs of diabetic cerebral microangiopathy.

Conditional Control of Instrumental Avoidance by Context Following Extinction

Using rodents, three training arrangements (i.e., ABB vs. ABA, AAA vs. AAB and ABB vs. ABC) explored whether extinction influences the expression of avoidance in a manner controlled by context. Retention testing following extinction showed that more avoidance responding (i.e., renewal) was observed when extinguished cues were tested outside of the context where they had undergone extinction. In contrast, response rates were significantly lower when stimuli were tested within the context where extinction learning had occurred. These findings add to the emerging literature assessing the role of Pavlovian extinction processes in the development of instrumental avoidance responding by demonstrating conditional control over extinguished responding by context. This study was conducted using a within-subjects approach that minimized the potential for context-outcome associations to bias responding, and thus, reflects hierarchical control over behavior based on the specific associative status of each tested cue in each training context.

SUFFICIENT ACTIVITY OF THE UBIQUITIN PROTEASOME SYSTEM IN AGED MICE AND DURING RETINAL DEGENERATION SUPPORTS DHFR-BASED CONDITIONAL CONTROL OF PROTEIN ABUNDANCE IN THE RETINA

SummaryThe Escherichia coli dihydrofolate reductase (DHFR) destabilizing domain (DD) serves as a promising approach to conditionally regulate protein abundance in a variety of tissues. In the absence of TMP, a DHFR stabilizer, the DD is degraded by the ubiquitin proteasome system (UPS). To test whether this approach could be effectively applied to a wide variety of aged and disease-related ocular mouse models, which may have a compromised UPS, we evaluated the DHFR DD system in aged mice (up to 24 mo), a light-induced retinal degeneration (LIRD) model, and two genetic models of retinal degeneration (rd2 and Abca4−/− mice). Aged, LIRD, and Abca4−/− mice all had similar proteasomal activities and high-molecular weight ubiquitin levels compared to control mice. However, rd2 mice displayed compromised chymotrypsin activity compared to control mice. Nonetheless, the DHFR DD was effectively degraded in all model systems, including rd2 mice. Moreover, TMP increased DHFR DD-dependent retinal bioluminescence in all mouse models, however the fold induction was slightly, albeit significantly, lower in Abca4−/− mice. Thus, the destabilized DHFR DD-based approach allows for efficient control of protein abundance in aged mice and retinal degeneration mouse models, laying the foundation to use this strategy in a wide variety of mice for the conditional control of gene therapies to potentially treat multiple eye diseases.

Chemical Synthesis of Stimuli-Responsive Guide RNA for Conditional Control of CRISPR-Cas9 Gene Editing

CRISPR-Cas9 promotes changes in identity or abundance of nucleic acids in live cells and is a programmable modality of broad biotechnological and therapeutic interest. To reduce off-target effects, tools for...

Coniferous plants root system formation in plantations of Izhevsk (Udmurt Republic)

A study of the root systems of tree species, their distribution in soil in horizontal and vertical directions, expressed by quantitative and qualitative indicators in the form of architectonics, underground phytomass, volume, surface, area and root saturation, answers many questions regarding the growth and development of tree plants. The growth conditions and species characteristics of plants have a significant effect on the formation of the root system.The studies were carried out in the large industrial center of the Ural region of Izhevsk in plantations of various environmental categories, i.e. plantings of the residential zone and plantings along the highways. As a zone of conditional control, a city park of landscape type named after S.M. Kirov. The objects of the study were coniferous species: the representative of the local flora such as European spruce (Pícea ábies L.) and the introduced species — Blue spruce (Picea pungens Engelm.), prevailing among the coniferous species used in the city’s landscaping. In the course of the research, the peculiarities of P. pungens and P. ábies in the formation of the root system in an anthropogenic environment were revealed, manifested in a change in the root saturation index of the meter soil layer, the length of the roots, the ratio of root fractions and their distribution in soil horizons. The total root saturation of a meter layer of soil is higher in P. pungens, but under the conditions of the highest technogenic load in the mainline stands, this indicator is higher in P. ábies. In park plantings in both species, the maximum root saturation was noted in the first soil horizon, while the anthropogenic load in P. ábies increased in the second horizon, and in P. pungens in the third soil horizon. The proportion of different root fractions also changes. P. pungens increases the proportion of semi-skeletal roots, P. ábies increses skeletally, and in conditions of high anthropogenic load it makes half-skeleton and suction roots.

Controlling Phosphate Removal with Light: The Development of Optochemical Tools to Probe Protein Phosphatase Function

Protein phosphatases play an essential role in cell signaling; however, they remain understudied compared with protein kinases, in part due to a lack of appropriate tools. In order to provide conditional control over phosphatase function, we developed two different approaches for rendering MKP3 (a dual-specific phosphatase, also termed DUSP6) activatable by light. Specifically, we expressed the protein with strategically placed light-removable protecting groups in cells with an expanded genetic code. This allowed for the acute perturbation of the Ras/MAPK signaling pathway upon photoactivation in live cells. In doing so, we confirmed that MKP3 does not act as a thresholding gate for growth factor stimulation of the extracellular signal-regulated kinase (ESRK) pathway.