The congenital cataract-causing mutations P20R and A171T are associated with important changes in the amyloidogenic feature,structure and chaperone-like activity of human αB-crystallin

Cataract is the major reason for human blindness worldwide. α-Crystallin, as a key chaperone of eye lenses, keeps the lenticular tissues in its transparent state over time. In this study, cataract-causing familial mutations, P20R and A171T, were introduced in CRYАB gene. After successful expression in Escherichia coli and subsequent purification, the recombinant proteins were subjected to extensive structural and functional analyses using various spectroscopic techniques, gel electrophoresis, and electron microscopy. The results of fluorescence and Raman assessments suggest important but discreet conformational changes in human αB-Cry upon these cataractogenic mutations. Furthermore, the mutant proteins exhibited significant secondary structural alteration as revealed by FTIR and Raman spectroscopy. An increase in conformational stability was seen in the human αB-Cry bearing these congenital cataractogenic mutations. The oligomeric size distribution and chaperone-like activity of human αB-Cry were significantly altered by these mutations. The P20R mutant protein was observed to loose most of the chaperone-like activity. Finally, these cataractogenic mutant proteins exhibited an increased propensity to form the amyloid fibrils when incubated under environmental stress. Overall, the structural and functional changes in mutated human αB-Cry proteins can shed light on the pathogenic development of congenital cataracts.     

Hybrid nanoreservoirs based on dextran-capped dendritic mesoporous silica nanoparticles for CD133-targeted drug delivery

In this study, the chemical features of dendritic mesoporous silica nanoparticles (DMSNs) provided the opportunity to design a nanostructure with the capability to intelligently transport the payload to the tumor cells. In this regard, doxorubicin (DOX)-encapsulated DMSNs was electrostatically surface-coated with polycarboxylic acid dextran (PCAD) to provide biocompatible dextran-capped DMSNs (PCAD-DMSN@DOX) with controlled pH-dependent drug release. Moreover, a RNA aptamer against a cancer stem cell (CSC) marker, CD133 was covalently attached to the carboxyl groups of DEX to produce a CD133-PCAD-DMSN@DOX. Then, the fabricated nanosystem was utilized to efficiently deliver DOX to CD133+ colorectal cancer cells (HT29). The in vitro evaluation in terms of cellular uptake and cytotoxicity demonstrated that the CD133-PCAD-DMSN@DOX specifically targets HT29 as a CD133 overexpressed cancer cells confirmed by flow cytometry and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay. The potentially promising intelligent-targeted platform suggests that targeted dextran-capped DMSNs may find impressive application in cancer therapy.     

Real-time observation of structure and dynamics during the liquid-to-solid transition of FUS LC

A subset of the proteins found in pathological protein fibrils also exhibit tendencies for liquid-liquid phase separation (LLPS) both in vitro and in cells. The mechanisms underlying the connection between these phase transitions have been challenging to study due to the heterogeneous and dynamic nature of the states formed during the maturation of LLPS protein droplets into gels and solid aggregates. Here, we interrogate the liquid-to-solid transition of the low-complexity domain of the RNA-binding protein FUS (FUS LC), which has been shown to adopt LLPS, gel-like, and amyloid states. We employ magic-angle-spinning NMR spectroscopy, which has allowed us to follow these transitions in real time and with residue-specific resolution. We observe the development of β-sheet structure through the maturation process and show that the final state of FUS LC fibrils produced after LLPS is distinct from that grown from fibrillar seeds. We also apply our methodology to FUS LC G156E, a clinically relevant FUS mutant that exhibits accelerated fibrillization rates. We observe significant changes in dynamics during the transformation of the FUS LC G156E construct and begin to unravel the sequence specific contributions to this phenomenon with computational studies of the phase-separated state of FUS LC and FUS LC G156E.     

Prey preference and prey switching in Anthocoris minki Dohrn (Hemiptera: Anthocoridae)

The understanding of host specificity of predacious insects is one of the most important problems in the investigation of biological control. Prey preference and the potential for prey switching in Anthocoris minki Dohrn (Hem.: Anthocoridae) was assessed in two- choice experiments under environmentally controlled conditions. Manly's preference index was used to compare A. minki predation on Agonoscena pistaciae Burckhardt and Lauterer (Hem.: Psyllidae) versus Psyllopsis repens Loginova (Hem.: Psyllidae) but showed no statistically significant evidence for preference. Anthocoris minki did prefer psyllids (Agonoscena pistaciae and Psyllopsis repens) over aphids (Forda hirsuta Mordvilko (Hem.: Pemphigidae) and Aphis craccivora Koch (Hem.: Aphididae)). The predator also consumed significantly more 2nd instar than 4th instar nymphs of P. repens. Switching behavior experiments showed that A. minki did not preferentially attack the most abundant prey when the prey combination was either biased toward A. pistaciae or toward F. hirsuta. Linear regression between preference indices and prey ratios indicated an overall preference for psyllids over aphids. The results suggest that a psyllid-specialized feeder such as A. minki is more likely to be effective biocontrol agent against psyllid species and less effective at reducing the numbers of other pest species that might co-occur with psyllids.     

Design,Synthesis, and Cholinesterase Inhibition Assay of Coumarin‐3‐carboxamide‐N‐morpholine Hybrids as New Anti‐Alzheimer Agents

A new series of coumarin‐3‐carboxamide‐N‐morpholine hybrids 5a – 5l was designed and synthesized as cholinesterases inhibitors. The synthetic approach for title compounds was started from the reaction between 2‐hydroxybenzaldehyde derivatives and Meldrum's acid to afford corresponding coumarin‐3‐carboxylic acids. Then, amidation of the latter compounds with 2‐morpholinoethylamine or N‐(3‐aminopropyl)morpholine led to the formation of the compounds 5a – 5l . The in vitro inhibition screen against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) revealed that most of the synthesized compounds had potent AChE inhibitory while their BuChE inhibitions are moderate to weak. Among them, propylmorpholine derivative 5g (N‐[3‐(morpholin‐4‐yl)propyl]‐2‐oxo‐2H‐chromene‐3‐carboxamide) bearing an unsubstituted coumarin moiety and ethylmorpholine derivative 5d (6‐bromo‐N‐[2‐(morpholin‐4‐yl)ethyl]‐2‐oxo‐2H‐chromene‐3‐carboxamide) bearing a 6‐bromocoumarin moiety showed the most activity against AChE and BuChE, respectively. The inhibitory activity of compound 5g against AChE was 1.78 times more than that of rivastigmine and anti‐BuChE activity of compound 5d is approximately same as rivastigmine. Kinetic and docking studies confirmed the dual binding site ability of compound 5g to inhibit AChE.     

Mechanisms of statin-induced new-onset diabetes

Statins, with their lipid-lowering properties, are a first-line therapy for the prevention of cardiovascular diseases. Recent evidence, however, suggests that statins can increase the risk of new-onset diabetes (NOD). The molecular mechanisms of statin-induced NOD are not precisely known, although some pathophysiologic mechanisms have been suggested. Specific to the beta cell, these mechanisms include alterations in insulin secretion, changes in ion channels, modulation of signaling pathways, and inflammation/oxidative stress. Outwith the beta cell, other suggested mechanisms involve adipocytes, including alterations in adipocyte differentiation and modulation of leptin and adiponectin, and genetic and epigenetic mechanisms, including alterations in microRNA. The evidence supporting these and other mechanisms will be discussed. Greater understanding of the underlying mechanisms linking the onset of diabetes to statin therapy is essential and clinically relevant, as it may enable novel preventative or therapeutic approaches to be instituted and guide the production of a new generation of statins lacking this side effect.     

Stem cell therapy: A novel approach for myocardial infarction

Myocardial infarction (MI) is a major cause of morbidity and mortality worldwide. Until recently, it was thought that myocardium was not able to repair itself, but studies have now shown that resident cardiac stem cells have regenerative capacity, and stem cell therapy may be a novel approach for cardiac muscle repair and regeneration. Stem cell-derived paracrine factors have been shown to regulate ventricular remodeling, inflammation, apoptosis, cardiomyocytes regeneration, and neovascularization in regions of infarcted cardiac tissue. In this review, we summarize the evidence from cellular, animal, and clinical studies supporting the potential clinical significance of stem cell therapy as a novel therapeutic approach for the treatment of MI.