Target-specific Approach Research Articles

To Explore the Putative Molecular Targets of Diabetic Nephropathy and their Inhibition Utilizing Potential Phytocompounds.

This review critically addresses the putative molecular targets of Diabetic Nephropathy (DN) and screens effective phytocompounds that can be therapeutically beneficial, and highlights their mechanistic modalities of action. DN has become one of the most prevalent complications of clinical hyperglycemia, with individual-specific variations in the disease spectrum that leads to fatal consequences. Diverse etiologies involving oxidative and nitrosative stress, activation of polyol pathway, inflammasome formation, Extracellular Matrix (ECM) modifications, fibrosis, and change in dynamics of podocyte functional and mesangial cell proliferation adds up to the clinical complexity of DN. Current synthetic therapeutics lacks target-specific approach, and is associated with the development of inevitable residual toxicity and drug resistance. Phytocompounds provides a vast diversity of novel compounds that can become an alternative therapeutic approach to combat the DN. Relevant publications were searched and screened from research databases like GOOGLE SCHOLAR, PUBMED and SCISEARCH. Out of 4895 publications, the most relevant publications were selected and included in this article. This study critically reviews over 60 most promising phytochemical and provides with their molecular targets, that can be of pharmacological significance in context to current treatment and concomitant research in DN. This review highlights those most promising phytocompounds that have the potential of becoming new safer naturally-sourced therapeutic candidates and demands further attention at clinical level.

Technical note: Patient-specific quality assurance for multi-target single-isocenter SRS-A target-specific approach.

As radiotherapy techniques advance, so do planning methods for multi-target intracranial SRS cases. Multi-target-single-isocenter (MTSI) planning offers high-precision beam delivery with shortened duration. However, accommodating all targets in a single Patient-Specific-Quality-Assurance (PSQA) with QA devices like SRS MapCHECK (SRS MC) is generally impractical. Consequently, we conducted PSQA, using a custom script, by relocating each Target or Neighboring-Target-Group (T-NTG) relative to the beam isocenter on the PSQA device, ensuring each target's dose coverage at high precision. SRS treatment plans use 6MV-FFF beams, consisting of four Volumetric Modulated ARC Therapy (VMAT) arcs, including one full-arc and three half arcs with couch-kicks. A custom script calculated T-NTG coordinates relative to the beam isocenter. QA verification plans were created for each T-NTG, redefining the beam isocenter for precise alignment with the center of the SRS MC. CBCT images were acquired during PSQA for SRS MC alignment, and gamma-index analysis (GIA) was performed. A single-tail paired t-test assessed the passing rate (PR) for 75 QA verification plans. GIA with l.0mm/2.0% criteria for each QA plan yielded a PR>95.5%, with an average of 98.9%. Plans achieving PR>99.0% and>97.0% constituted 63% and 92% of studied plans, respectively. Statistical significance was observed in a t-test with an ideal PR value of 100%, while insignificance was found with a PR value of 99%, suggesting that PSQA for individual targets consistently approaches 99% PR. In MTSI cases using 6MV-FFF beams, targets within the lateral dose-fall-off region require careful verification for acceptability. Our clinical study on individual T-NTG relocation demonstrates that the presented PSQA methods are generally acceptable, supported by a statistically insignificant PR against a 99% PR value. Presented statistical analysis results indicate that the proposed PSQA approach can serve as a reliable tool in clinical settings.

Nanodelivery systems: An efficient and target-specific approach for drug-resistant cancers.

Cancer treatment is still a global health challenge. Nowadays, chemotherapy is widely applied for treating cancer and reducing its burden. However, its application might be in accordance with various adverse effects by exposing the healthy tissues and multidrug resistance (MDR), leading to disease relapse or metastasis. In addition, due to tumor heterogeneity and the varied pharmacokinetic features of prescribed drugs, combination therapy has only shown modestly improved results in MDR malignancies. Nanotechnology has been explored as a potential tool for cancer treatment, due to the efficiency of nanoparticles to function as a vehicle for drug delivery. With this viewpoint, functionalized nanosystems have been investigated as a potential strategy to overcome drug resistance. This approach aims to improve the efficacy of anticancer medicines while decreasing their associated side effects through a range of mechanisms, such as bypassing drug efflux, controlling drug release, and disrupting metabolism. This review discusses the MDR mechanisms contributing to therapeutic failure, the most cutting-edge approaches used in nanomedicine to create and assess nanocarriers, and designed nanomedicine to counteract MDR with emphasis on recent developments, their potential, and limitations. Studies have shown that nanoparticle-mediated drug delivery confers distinct benefits over traditional pharmaceuticals, including improved biocompatibility, stability, permeability, retention effect, and targeting capabilities.

Abstract 8: Differential flt3 mutational status in acute myeloid leukemia predicts sensitivity to flt3 inhibitor gilteritinib in vitro and in vivo

Abstract Acute Myeloid Leukemia (AML) is a heterogenous hematopoietic cancer characterized by abnormal differentiation and uncontrolled proliferation of hematopoietic progenitor cells. Recent approaches to treatment, which aim to improve outcomes in refractory AML, include strategies to molecularly target specific receptor-mediated signaling pathways which regulate cell growth and proliferation. One target-specific approach is the inhibition of fms-like tyrosine kinase 3 (FLT3). FLT3 is expressed on the surface of hematopoietic progenitor cells and plays an important role in regulating proliferation, survival, and differentiation of multipotent stem cells. The presence of internal tandem duplications (ITDs) at the juxta membrane domain within the FLT3 receptor are common driver mutations in 30% of AML patients. In this study, we utilized 3 luciferase-expressing human AML models, MV4-11, MOLM-13, and, OCI-AML3 to determine the prognostic impact of FLT3 inhibitor Gilteritinib on the allelic ratio of ITD versus wildtype allele. OCI-AML3 expresses wild-type FLT3 whereas MOLM-13 is heterozygous for FLT3-ITD mutations, and MV4-11 possesses a homozygous in-frame tandem repeat insertion in the FLT3 allele. Here we demonstrate that FLT3-ITD mutational status impacts the efficacy of Gilteritinib in both in vitro and in vivo AML models. The in vitro assays showed that treatment with Gilteritinib resulted in significant dose dependent reduction in overall cell viability and bioluminescence in the MV4-11 cell line, while MOLM-13 was only moderately sensitive, and OCI-AML3 was least sensitive to Gilteritinib treatment. Additionally, we evaluated the downstream MAPK and PI3K signaling pathways as FLT3-ITD oncogenic mutations result in ligand-independent constitutive activation of signaling pathways mediating leukemic transformation. For in vivo validation, MV4-11, MOLM-13, and OCI-AML3 luciferase expressing cells were implanted systemically into NCG mice and once tumors were established, we evaluated the survival benefit in response to Gilteritinib and various standard of care agents. In accordance with our in vitro findings, the quantification of tumor progression by bioluminescent imaging showed the highest therapeutic activity of Gilteritinib in MV4-11 tumor bearing mice through selective targeting of FLT3-ITD mutations. Taken together, our in vitro and in vivo results demonstrate that differential FLT3-ITD mutational status in AML models impacts Gilteritinib treatment response and downstream signaling events with the highest activity in MV4-11 followed by MOLM-13, and lack of activity in OCI-AML3 harboring wild-type FLT3. Citation Format: Bincy John, Pasupathi Sundaramoorthy, Elizabeth Rainbolt, Andrew Wong, Zachary Ward, Justin Avery, Savannah Todd, Shasta Kidder, Diana Gietl, Chassidy Hall, David Harris. Differential flt3 mutational status in acute myeloid leukemia predicts sensitivity to flt3 inhibitor gilteritinib in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 8.

TCF-1 Is Required for CD4 T Cell Persistence Functions during AlloImmunity

The transcription factor T cell factor-1 (TCF-1) is encoded by Tcf7 and plays a significant role in regulating immune responses to cancer and pathogens. TCF-1 plays a central role in CD4 T cell development; however, the biological function of TCF-1 on mature peripheral CD4 T cell-mediated alloimmunity is currently unknown. This report reveals that TCF-1 is critical for mature CD4 T cell stemness and their persistence functions. Our data show that mature CD4 T cells from TCF-1 cKO mice did not cause graft versus host disease (GvHD) during allogeneic CD4 T cell transplantation, and donor CD4 T cells did not cause GvHD damage to target organs. For the first time, we showed that TCF-1 regulates CD4 T cell stemness by regulating CD28 expression, which is required for CD4 stemness. Our data showed that TCF-1 regulates CD4 effector and central memory formation. For the first time, we provide evidence that TCF-1 differentially regulates key chemokine and cytokine receptors critical for CD4 T cell migration and inflammation during alloimmunity. Our transcriptomic data uncovered that TCF-1 regulates critical pathways during normal state and alloimmunity. Knowledge acquired from these discoveries will enable us to develop a target-specific approach for treating CD4 T cell-mediated diseases.

In planta transformation of Polianthes tuberosa for concomitant knockdown of flp-1, flp-12 and flp-18 genes induced root-knot nematode resistance

Polianthes tuberosa is a lucrative crop owing to its huge demand in floriculture, perfume and pharmaceutical industry. Root-knot nematodes, especially Meloidogyne incognita poses a major impediment on tuberose yield. Currently nematode management relies on the use of hazardous nematicides and other inefficacious means viz. crop rotation and soil solarization. The ongoing search for an ecologically sustainable and target specific approach, led to the progression of genetic modification based techniques to target genes critical for nematode survival. FMRFamide like peptide (FLPs) genes have drawn interest as prospective targets because of their diverse physiological roles in nematodes. Here, the effect of concomitant silencing of three vital nematode FLP genes (Mi-flp-1, Mi-flp-12 and Mi-flp-18) using host induced RNAi in tuberose was assessed against M. incognita. Firstly, the fusion (flp-1, flp-12 and flp-18) gene cassette was functionally validated using host-delivered RNAi in tobacco model system. Transgenic tobacco expressing dsRNA of fusion gene significantly reduced the nematode multiplication factor (MF) by 82.6%. Since, genetic transformation of tuberose has been neglected so far, and transgenic development is an inevitable step for host-generated RNAi, an Agrobacterium mediated transformation protocol was optimized in tuberose. Tuberose tubers were pricked at the apical meristem of the axis and at the tiny white meristematic buds emerging from them, followed by infection with Agrobacterium hosting pCAMBIA 3301 vector. Maximum transformation efficiency was achieved with 200 μM acetosyringone as observed from the GUS staining. For HIGS, fusion transgenic events were developed in tuberose and molecular analysis confirmed the presence and integration of fusion transgene using PCR, qRT-PCR and Southern blot analysis. Bioefficacy analysis of transgenic plants against M. incognita resulted in 73.75% reduction in nematode fecundity, thereby demonstrating the effectiveness of the three flp genes for nematode management in tuberose. This study established first ever report of in planta Agrobacterium-mediated transformation of tuberose for host delivered RNAi for M. incognita resistance.

Role of Bioactive Phytoconstituents as Modulators of Hepatic Carbohydrates Metabolising Enzymes: A Target Specific Approach to Treat Diabetes Mellitus.

Diabetes mellitus is the most prevalent malady, becoming a leading public health concern around the world. It is a chronic endocrine metabolic disturbance that is accompanied by the commencement of a sequence of complications. The liver primarily serves as the body's glucose or fuel reserve and also maintains standard blood sugar concentration. Hepatic gluconeogenesis, glycolysis and glycogenesis are the key contributors to fasting or post-prandial hyperglycaemia in type 2 diabetes mellitus subjects. So, regulating these channels could be a viable approach for mitigating hyperglycaemia in type 2 diabetes mellitus. Few potential synthetic drugs that precisely target hepatic glucose-producing metabolic pathways are presently available, but they have some serious negative effects like hypoglycaemia, hepatosteatosis and lactic acidosis. Therefore, scientists have veered to herbal products because of their edible nature, costeffectiveness and fewer side effects. Natural products and their isolated phytochemicals are progressively being employed to manage hyperglycaemia by modulating the enzyme's activity and regulating transcription factors concerned with hepatic glucose synthesis. We reviewed the potential effects of isolated bioactive phytochemicals on interesting targets that affect hepatic glucose homeostasis in diabetes. This study illustrates the benefit and feasibility of developing liver-specific drugs through secondary metabolites to restore hyperglycaemia.

Patient-derived Siglec-6-targeting antibodies engineered for T-cell recruitment have potential therapeutic utility in chronic lymphocytic leukemia

BackgroundDespite numerous therapeutic options, safe and curative therapy is unavailable for most patients with chronic lymphocytic leukemia (CLL). A drawback of current therapies such as the anti-CD20 monoclonal antibody (mAb)...

Universal adaptability: Target-independent inference that competes with propensity scoring

The gold-standard approaches for gleaning statistically valid conclusions from data involve random sampling from the population. Collecting properly randomized data, however, can be challenging, so modern statistical methods, including propensity score reweighting, aim to enable valid inferences when random sampling is not feasible. We put forth an approach for making inferences based on available data from a source population that may differ in composition in unknown ways from an eventual target population. Whereas propensity scoring requires a separate estimation procedure for each different target population, we show how to build a single estimator, based on source data alone, that allows for efficient and accurate estimates on any downstream target data. We demonstrate, theoretically and empirically, that our target-independent approach to inference, which we dub "universal adaptability," is competitive with target-specific approaches that rely on propensity scoring. Our approach builds on a surprising connection between the problem of inferences in unspecified target populations and the multicalibration problem, studied in the burgeoning field of algorithmic fairness. We show how the multicalibration framework can be employed to yield valid inferences from a single source population across a diverse set of target populations.

Waveform Optimization for Multistatic Radar Imaging Using Mutual Information

This article addresses the problem of radar waveform design for imaging targets in a cluttered environment. A multistatic radar scenario is considered for sparse and random sensor positions. The target impulse response is modeled using the simulated frequency response of a buried metallic mine, and the clutter is modeled using the compound Gaussian (CG) distribution. We explore novel waveform design techniques with respect to the mutual information (MI) criterion based on the CG clutter. The first method presents a waveform that exploits the CG distribution of the scene reflectivity function when projected onto a sparse basis. This is compared to the second method, called the target-specific approach that uses knowledge of the target and clutter frequency responses to optimize a matched illumination waveform. In both cases, the Taguchi and particle swarm optimization solvers are employed for MI-based waveform design optimization. To validate and compare the effectiveness of the optimized waveforms, the resulting scene reflectivity function is estimated using the sparsity-driven regularization radar imaging method. Our experimental results demonstrate that both waveform optimization techniques result in significantly better image reconstruction performance than the traditional linear-frequency-modulated waveform, and that the target-specific approach additionally suppresses clutter information in the scene.

Therapeutic progression of quinazolines as targeted chemotherapeutic agents.

Presently cancer is a grave health issue with predominance beyond restrictions. It can affect any organ of the body. Most of the available chemotherapeutic drugs are highly toxic, not much selective and eventually lead to the development of resistance. Therefore, a target specific palliative approach for the treatment of cancer is required. Remarkable advancements in science have illuminated various molecular pathways responsible for cancer. This has resulted in abundant opportunities to develop targeted anticancer agents. Quinazoline nucleus is a privileged scaffold with significant diversified pharmacological activities. Numerous established anticancer quinazoline derivatives constitute a new class of chemotherapeutic agents which are found to act by inhibiting various protein kinases as well as other molecular targets. A recent update on various quinazoline derivatives acting on different types of molecular targets for the treatment of cancer has been compiled in this review. Brief SAR studies of quinazoline derivatives acting through different mechanisms of action have been highlighted. The comprehensive medicinal chemistry aspects of these agents in this review provide a panoramic view to the biologists as well as medicinal chemists working in this area and would assist them in their efforts to design and synthesize novel quinazoline based anticancer compounds.

2,4-Thiazolidinediones as PTP 1B Inhibitors: A Mini Review (2012-2018).

2,4-thiazolidinedione (TZD) scaffold is a synthetic versatile scaffold explored by medicinal chemists for the discovery of novel molecules for the target-specific approach to treat or manage number of deadly ailments. PTP 1B is the negative regulator of insulin signaling cascade, and its diminished activity results in abolishment of insulin resistance associated with T2DM. The present review focused on the seven years journey (2012-2018) of TZDs as PTP 1B inhibitors with the insight into the amendments in the structural framework of TZD scaffold in order to optimize/design potential PTP 1B inhibitors. We have investigated the synthesized molecules based on TZD scaffold with potential activity profile against PTP 1B. Based on the SAR studies, the combined essential pharmacophoric features of selective and potent TZDs have been mapped and presented herewith for further design and synthesis of novel inhibitors of PTP 1B. Compound 46 bearing TZD scaffold with N-methyl benzoic acid and 5-(3-methoxy-4-phenethoxy) benzylidene exhibited the most potent activity (IC50 1.1 µM). Imidazolidine-2,4-dione, isosteric analogue of TZD, substituted with 1-(2,4-dichlorobenzyl)-5-(3-(2,4- dichlorobenzyloxy)benzylidene) (Compound 15) also endowed with very good PTP inhibitory activity profile (IC50 0.57 µM). It is noteworthy that Z-configuration is essential in structural framework around the double bond of arylidene for the designing of bi-dentate ligands with optimum activity.

In vivo Protein Evolution, Next Generation Protein Engineering Strategy: from Random Approach to Target-specific Approach

In vivo protein evolution is a protein engineering approach that is performed by both generating mutagenesis libraries and selecting desired mutants in a cell. Despite its clear advantages in some aspects, the approach has not much been popularized compared to in vitro protein evolution methods which employ in vitro mutagenesis. The reason behind this unpopularity is the limitations in the low library diversity and specificity of in vivo mutagenic methods compared to those of in vitro mutagenic methods. While various non-specific and specific in vitro mutagenic methods, which allowed us to use computational design principles as well as random approach in the design of mutant library, had been developed, in vivo mutagenic methods were stalled at the step of random mutagenesis since the in vivo generation of target-specific library with high specificity and broad mutational spectra is quite challenging. Recently, various in vivo protein mutagenesis methods have been developed to generate rather focused libraries in a target-specific manner, thanks to the significant decrease in the price of oligomer synthesis and better understanding of DNA targeting systems. In this review, we examined the trends of in vivo protein evolution and inspect some of the state-of-the-art techniques that were recently introduced for in vivo protein mutagenesis in a target-specific manner. In vivo protein mutagenesis is a subject undergoing intense study and will become more specific and thorough simultaneously.

Biomining of MoS2 with Peptide-based Smart Biomaterials

Biomining of valuable metals using a target specific approach promises increased purification yields and decreased cost. Target specificity can be implemented with proteins/peptides, the biological molecules, responsible from various structural and functional pathways in living organisms by virtue of their specific recognition abilities towards both organic and inorganic materials. Phage display libraries are used to identify peptide biomolecules capable of specifically recognizing and binding organic/inorganic materials of interest with high affinities. Using combinatorial approaches, these molecular recognition elements can be converted into smart hybrid biomaterials and harnessed for biotechnological applications. Herein, we used a commercially available phage-display library to identify peptides with specific binding affinity to molybdenite (MoS2) and used them to decorate magnetic NPs. These peptide-coupled NPs could capture MoS2 under a variety of environmental conditions. The same batch of NPs could be re-used multiple times to harvest MoS2, clearly suggesting that this hybrid material was robust and recyclable. The advantages of this smart hybrid biomaterial with respect to its MoS2-binding specificity, robust performance under environmentally challenging conditions and its recyclability suggests its potential application in harvesting MoS2 from tailing ponds and downstream mining processes.

Exploiting the Sensitivity of Nutrient Transporter Deletion Strains in Discovery of Natural Product Antimetabolites

Actinomycete secondary metabolites are a renowned source of antibacterial chemical scaffolds. Herein, we present a target-specific approach that increases the detection of antimetabolites from natural sources by screening actinomycete-derived extracts against nutrient transporter deletion strains. On the basis of the growth rescue patterns of a collection of 22 Escherichia coli (E. coli) auxotrophic deletion strains representative of the major nutrient biosynthetic pathways, we demonstrate that antimetabolite detection from actinomycete-derived extracts prepared using traditional extraction platforms is masked by nutrient supplementation. In particular, we find poor sensitivity for the detection of antimetabolites targeting vitamin biosynthesis. To circumvent this and as a proof of principle, we exploit the differential activity of actinomycete extracts against E. coli ΔyigM, a biotin transporter deletion strain versus wildtype E. coli. We achieve more than a 100-fold increase in antimetabolite sensitivity using this method and demonstrate a successful bioassay-guided purification of the known biotin antimetabolite, amiclenomycin. Our findings provide a unique solution to uncover the full potential of naturally derived antibiotics.

Association of bone morphogenic protein 4 gene polymorphism and left ventricle hypertrophy in diabetic chronic kidney disease patients: A pilot study

BackgroundThe Bone Morphogenetic Protein 4 (BMP4) is identified to play a significant role in cardiac remodelling; gene polymorphism and its resulting associations with Left Ventricular Hypertrophy (LVH) in diabetic Chronic Kidney Disease (CKD) patients of this protein are yet to be established. AimTo analyse the association between BMP4 gene polymorphism and LVH in diabetic CKD patients. Materials and methodsIsolation of DNA from whole blood samples of 50 patients each; patients diagnosed LVH with diabetic CKD and also from LVH patients without diabetic CKD, diabetic CKD without LVH and also normal patients as control were extracted. The gene of interest (BMP4 gene) purified from various samples digested using zero-cutter restriction endonucleases (Hind III and Bam HI) by employing the Restriction Fragment Length Polymorphism (RFLP) technique. The restriction has been analysed using 1% agarose gel Electrophoresis. ResultsThe gene from patient having LVH without diabetic CKD when digested with Hind III showed fragmentation, more specifically, it presented three/four fragments which were at a comparable distance corresponding with the following size reference markers at 2000bp(few cases), 1500bp, between 700–600bp and the last one near 100bp. This fragmentation pattern was repeated identically for the gene from blood sample of patient having LVH with diabetic CKD which was also digested with Hind III. A similar fragmentation was not visualized for sample from patient having diabetic CKD without LVH when digested with Hind III. But no such fragments were noted for the samples from the same patients when digested with Bam HI. ConclusionBMP4 gene polymorphism has been confirmed in patients having LVH regardless of the presence or absence of diabetic CKD along with it. Focal points•Benchside:Left ventricular (LV) hypertrophy is a strong autonomous predictor of increased cardiovascular morbidity and mortality in clinical and population-based samples. Thus understanding the correlation of LVH with BMP4 gene is necessitated to provide alternate therapeutics strategy at genome level. Eventually, genetic investigations provide high assurance for future prevention, early intervention and treatment of this major public health issue.•Bedside:Determination of BMP4 Polymorphism would raise a new drug development target using single nucleotide polymorphism. They also serve as molecular marker for next generation therapeutics of personalized medicine at genome level.•Community:The patient's therapeutic quality would be high due target specific approach with the understanding of personalized medicine. This can prevent unwanted treatment that can guide way to side-effects in the system.•Governments:Funding bodies should continue to acknowledge the importance that the BMP4 gene plays a role in LVH, which can be a causative agent for many other cardio-disorders. Overtime, this will help in benefiting patients and healthcare institutions.

Microbial Proteins as Novel Industrial Biotechnology Hosts to Treat Epilepsy.

Epilepsy is characterized by the hyperexcitability of various neuronal circuits that results due to the imbalance between glutamate-mediated excitation of voltage-gated cation channels and γ-amino butyric acid (GABA)-mediated inhibition of anion channels leading to aberrant, sporadic oscillations or fluctuations in neuronal electrical activity. Epilepsy with a risk of mortality and around 65 million sufferers of all ages all over the world is limited therapeutically with high rates of adverse reactions, lack of complete seizure control, and over 30% patients with refractory epilepsy. The only alternative to medicines is to identify and surgically remove the seizure foci in the brain or to abort the seizures just as they begin using an implanted cerebral electrode. However, these alternatives are unable to precisely aim aberrant neuronal circuits while leaving others unaltered. Epilepsy animal models also constitute the identical constraint. Thus, a better target-specific approach is needed to study and treat epilepsy. Unicellular green algae Chlamydomonas reinhardtii expresses a channelrhodopsin-2 (ChR2) sodium ion channel protein that controls the phototaxis movement of algae in response to blue light. Similarly, archaeon Natronomonas pharaonis (NpHR) expresses a monovalent Cl- channel protein halorhodopsin that responds to yellow light. These features of ChR2 and NpHR proteins can be used in optogenetic techniques to manipulate the bi-directional firing pattern of neuronal circuits in an attempt to better understand the pathophysiology of epileptic seizures as well as to discover novel potential drugs to treat epilepsy.

Exosome-mediated small RNA delivery for gene therapy.

Small RNAs, including small interfering RNAs (siRNA) and microRNAs (miRNA), are emerging as promising therapeutic drugs against a wide array of diseases. The key obstacle for the successful clinical application of small RNAs is to develop a safe delivery system directed at the target tissues only. Current small RNA transfer techniques use viruses or synthetic agents as delivery vehicles. The replacement of these delivery vehicles with a low toxicity and high target-specific approach is essential for making small RNA therapy feasible. Because exosomes have the intrinsic ability to traverse biological barriers and to naturally transport functional small RNAs between cells, they represent a novel and exciting delivery vehicle for the field of small RNA therapy. As therapeutic delivery agents, exosomes will potentially be better tolerated by the immune system because they are natural nanocarriers derived from endogenous cells. Furthermore, exosomes derived from genetically engineered cells can deliver small RNAs to target tissues and cells. Thus, exosome-based delivery of small RNAs may provide an untapped, effective delivery strategy to overcome impediments such as inefficiency, nonspecificity, and immunogenic reactions. In this review, we briefly describe how exosomal small RNAs function in recipient cells. Furthermore, we provide an update and overview of new findings that reveal the potential applications of exosome-based small RNA delivery as therapeutics in clinical settings. WIREs RNA 2016, 7:758-771. doi: 10.1002/wrna.1363 For further resources related to this article, please visit the WIREs website.

Status Differences in Target-Specific Prosocial Behavior and Aggression.

Previous studies exploring the link between social status and behavior have predominantly utilized measures that do not provide information regarding toward whom aggression or prosocial behavior is directed. Using a contextualized target-specific approach, this study examined whether high- and low-status adolescents behave differently toward peers of varying levels of status. Participants, aged 11-15 (N=426, 53% females), completed measures assessing aggression and prosocial behavior toward each same-sex grademate. A distinct pattern of findings emerged regarding the likeability, popularity, and dominance status of adolescents and their peer targets. Popular adolescents reported more direct aggression, indirect aggression, and prosocial behavior toward popular peers than did unpopular adolescents. Well-accepted adolescents reported more prosocial behavior toward a wider variety of peers than did rejected adolescents. Finally, compared to subordinate adolescents, dominant adolescents reported greater direct and indirect aggression toward dominant than subordinate peers. The results highlight the importance of studying target-specific behavior to better understand the status-behavior link.

Developing a Universal Steric Trapping Strategy for Studying Folding and Stability of Helical Membrane Proteins

“Steric trapping” is a method that links binding of monovalent streptavidin (mSA) to unfolding of a biotinylated protein (MP). It allowed the measurements of high affinity protein–protein interactions and thermodynamic stability of polytopic helical MPs in a native environment, which had been difficult to achieve using more conventional methods. In the current steric trapping framework, a conformation-sensitive chromophore or an enzymatic activity in a target MP is required for monitoring mSA-induced unfolding. This target-specific approach is a limiting factor that hinders its application to various MP systems, i.e. MPs in a misfolded conformation, MPs with an assembly role, or MPs without convenient unfolding readout. To further advance the steric trapping strategy for more general application, we have developed novel tripartite probes possessing a thiol-reactive group, a biotin group and a fluorescent or paramagnetic group for sensitization of unfolding or binding of mSA. We applied the new strategy to investigating the stability and unfolding mechanism of an intramembrane protease GlpG. By combining FRET between fluorescently labeled GlpG and quencher-labeled mSA as a measure of mSA binding and the proteolytic activity of GlpG as a measure of unfolding, we proved the thermodynamic coupling between binding and unfolding, and determined the thermodynamic stability and unfolding rate of GlpG in a native micellar environment. While the stabilities were similar independent of the location of biotin pairs, the unfolding was 20 times faster when the biotin pair was placed near the proteolytic active site. This result suggests a subdomain-organization of the helical bundle architecture of GlpG. Steric trapping may serve as a useful tool for elucidating the local versus global flexibility of helical MPs.