Albumin Expands Albumin Reabsorption Capacity in Proximal Tubule Epithelial Cells through a Positive Feedback Loop between AKT and Megalin

Renal proximal tubule cells (PTECs) act as urine gatekeepers, constantly and efficiently avoiding urinary protein waste through receptor-mediated endocytosis. Despite its importance, little is known about how this process is modulated in physiologic conditions. Data suggest that the phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT) pathway regulates PTEC protein reabsorption. Here, we worked on the hypothesis that the physiologic albumin concentration and PI3K/AKT pathway form a positive feedback loop to expand endocytic capacity. Using LLC-PK1 cells, a model of PTECs, we showed that the PI3K/AKT pathway is required for megalin recycling and surface expression, affecting albumin uptake. Inhibition of this pathway stalls megalin at EEA1+ endosomes. Physiologic albumin concentration (0.01 mg/mL) activated AKT; this depends on megalin-mediated albumin endocytosis and requires previous activation of PI3K/mTORC2. This effect is correlated to the increase in albumin endocytosis, a phenomenon that we refer to as “albumin-induced albumin endocytosis”. Mice treated with L-lysine present decreased albumin endocytosis leading to proteinuria and albuminuria associated with inhibition of AKT activity. Renal cortex explants obtained from control mice treated with MK-2206 decreased albumin uptake and promoted megalin internalization. Our data highlight the mechanism behind the capacity of PTECs to adapt albumin reabsorption to physiologic fluctuations in its filtration, avoiding urinary excretion.

Biodegradation of Keratin-Rich Husbandry Waste as a Path to Sustainable Agriculture

Every year, the size of the human population grows; with it, the need for agricultural products increases. This leads to an increment in the volume of waste, including hard-to-degrade keratin-rich ones, such as feathers. Currently, most of the agro-industrial complex protein by-products are utilized by incineration, landfilling, and chemical hydrolysis. Such methods do not meet modern trends in the development of a sustainable economy, negatively affecting the environment and humans, and preventing the reusing of waste. An alternative is biodegradation, which consists of the application of living organisms and their enzymes to recycle by-products. This approach is not only sustainable, but also makes it possible to obtain products of waste hydrolysis that are in demand for the manufacture of fertilizers and feed additives. This brings the development of agriculture closer to a circular economy and makes the recycling process more profitable. This review article emphasizes the significance of keratinolytic microorganisms and keratinases for the improvement of green methods for processing hard-to-degrade protein waste of the agro-industrial complex, which is necessary for sustainable economic development.

Smart biopolymers from protein wastes used in agriculture

The area of interest is the synthesis and study of properties of new types of hydrogels made from pelt waste, in order to recover waste from tanneries. The complex aspects related to protein projects in the leather industry are addressed by accurately determining a chemical composition, a skin designer and a different possibility of recovery and claiming a value, the use of biotechnology. The complex aspects related to protein waste in the leather industry are addressed by accurately determining the chemical composition of leather waste and the different possibilities of recovery and recycling using biotechnology. The technologies used in order to obtain a smart hydrogel based on collagen and natural polymers are non-polluting and waste-free. An important aspect to note is that the smart hydrogel is obtained through an almost identical technological process to the one used for medical collagen. An extensive study of the potential for reuse and recycling of leather protein waste in ecological conditions by developing innovative procedures for obtaining an NPK collagen matrix to be used successfully as smart fertilizer for modifying nutrient-poor soils. Hydrogels with collagen structure are characterized by a high-performance instrumental analysis system (FT-IR-ATR, SEM, EDAX, etc.).

Pelt waste degradation using active microbial consortia

In tanneries, environmental problems have special implications in terms of optimizing the consumption of used chemicals, applied technologies, the degree of recovery of useful substances from leather waste. Biodegradation is the process by which organic substances are broken down by microorganisms. From an ecological point of view, biodegradability assessments of new materials and compounds in the industry are essential to understand and quantify their impact on the environment. The sustainable development of the leather industry has focused on major environmental issues, such as clean production methods and waste management. Tanneries generate huge quantities of solid wastes as pelt waste. If these bio-waste materials are not utilized properly, they are potential source of pollution. Microbiological degradation of pelt waste is amongst the permanent concerns of leather processing units. The process may have the purpose of decomposing waste to exploit by-products as biocompost or to obtain proteases through a biotechnological process. These enzymes can be used after purification in various processes that have animal protein as a substrate. They can also be used in raw state for enzymatic hydrolysis. The paper aims at development of an experimental model on the bioenzymatic degradation process of protein waste from tanneries.

Glymphatic failure as a final common pathway to dementia

Sleep is evolutionarily conserved across all species, and impaired sleep is a common trait of the diseased brain. Sleep quality decreases as we age, and disruption of the regular sleep architecture is a frequent antecedent to the onset of dementia in neurodegenerative diseases. The glymphatic system, which clears the brain of protein waste products, is mostly active during sleep. Yet the glymphatic system degrades with age, suggesting a causal relationship between sleep disturbance and symptomatic progression in the neurodegenerative dementias. The ties that bind sleep, aging, glymphatic clearance, and protein aggregation have shed new light on the pathogenesis of a broad range of neurodegenerative diseases, for which glymphatic failure may constitute a therapeutically targetable final common pathway.