Boronic acid-rich dendrimer for efficient intracellular peptide delivery

Interests in intracellular peptide delivery have continued to grow,significantly fueled by the importance of peptides and their mimetics in modern cell biology and pharmaceutical industry.However,efficient intracellular delivery of membrane-impermeable peptides of different polarities remains a challenging task.In this study,we develop a general and robust strategy for intracellular peptide delivery by using a boronic acid-rich dendrimer.The designed material is capable of transporting peptides with different polarities and charge properties into the cytosol of various cell lines without inducing additional cytotoxicity.The transduction efficacy and proteolytic stability of cargo peptides delivered by the boronic acid-rich dendrimer are much superior to peptides conjugated with cell penetrant peptides such as octaarginine.In addition,the bioactivities of pro-apoptotic peptides are maintained after intracellular delivery.This study provides a versatile and robust platform for the intracellular delivery of membrane-impermeable peptides.

ISP and PAP4 peptides promote motor functional recovery after peripheral nerve injury

Both intracellular sigma peptide(ISP) and phosphatase and tensin homolog agonist protein(PAP4) promote nerve regeneration and motor functional recovery after spinal cord injury. However, the role of these two small peptides in peripheral nerve injury remains unclear. A rat model of brachial plexus injury was established by crush of the C6 ventral root. The rats were then treated with subcutaneous injection of PAP4(497 μg/d, twice per day) or ISP(11 μg/d, once per day) near the injury site for 21 successive days. After ISP and PAP treatment, the survival of motoneurons was increased, the number of regenerated axons and neuromuscular junctions was increased, muscle atrophy was reduced, the electrical response of the motor units was enhanced and the motor function of the injured upper limbs was greatly improved in rats with brachial plexus injury. These findings suggest that ISP and PAP4 promote the recovery of motor function after peripheral nerve injury in rats. The animal care and experimental procedures were approved by the Laboratory Animal Ethics Committee of Jinan University of China(approval No. 20111008001) in 2011.

COVID-19,liver dysfunction and pathophysiology:A conceptual discussion

The intra and extracellular pathways of hepatic injury by coronavirus disease 2019(COVID-19)are still being studied.Understanding them is important to treat this viral disease and other liver and biliary tract disorders.Thus,this paper aims to present three hypotheses about liver injury caused by COVID-19:(1)The interactions between severe acute respiratory syndrome coronavirus 2 spike protein and membrane receptors in the hepatocyte;(2)The dysbiosis and"gutliver axis"disruption in patients with serious clinical presentations of COVID-19;and(3)The inflammatory response exacerbated through the production of interleukins such as interleukin-6.However,despite these new perspectives,the pathophysiological process of liver injury caused by COVID-19 is still complex and multifactorial.Thus,understanding all these variables is a challenge to science but also the key to propose individualized and effective patient therapies.