Membrane Sites Research Articles

Janus polymer-grafted nanoparticles mimicking membrane repair proteins for the prevention of lipid membrane rupture.

Plasma membrane rupture often leads to cell damage, especially when there is a lack of membrane repair proteins near the wounds due to genetic mutations in organisms. To efficiently promote the repair of the injured lipid membrane, nanomedicines may act as a promising alternative to membrane repair proteins, but the related research is still in its infancy. Herein, using dissipative particle dynamics simulations, we designed a class of Janus polymer-grafted nanoparticles (PGNPs) that can mimic the function of membrane repair proteins. The Janus PGNPs comprise both hydrophobic and hydrophilic polymer chains grafted on nanoparticles (NPs). We track the dynamic process of the adsorption of Janus PGNPs at the damaged site in the lipid membrane and systematically assess the driving forces for this process. Our results reveal that tuning the length of the grafted polymer chains and the surface polarity of the NPs can efficiently enhance the adsorption of Janus PGNPs at the site of the damaged membrane to reduce membrane stress. After repair, the adsorbed Janus PGNPs can be successfully detached from the membrane, leaving the membrane untouched. These results provide valuable guidelines for designing advanced nanomaterials for the repair of damaged lipid membranes.

Negatively curved cellular membranes promote BAIAP2 signaling hub assembly.

Plasma membrane deformations are associated with curvature-dependent protein enrichment that contributes to a wide array of cellular functions. While the spatio-temporal protein dynamics at membrane indentations is well characterized, relatively little is known about protein kinetics at outwardly deforming membrane sites. This is in part due to the lack of high throughput approaches to systematically probe the curvature-dependence of protein-membrane interactions. Here, we developed a nanopatterned array for multiplexed analysis of protein dynamics at negatively curved cellular membranes. Taking advantage of this robust and versatile platform, we explored how membrane shape influences the prototypic negative curvature sensing protein BAIAP2 and its effector proteins. We find assembly of multi-protein signaling hubs and increased actin polymerization at outwardly deformed membrane sections, indicative of curvature-dependent BAIAP2 activation. Collectively, this study presents technical and conceptual advancements towards a quantitative understanding of spatio-temporal protein dynamics at negatively curved membranes.

Rationally designed molecularly imprinted polymer membranes as antibody and enzyme mimics in analytical biotechnology

The paper is a self-review of works on development of new approaches to formation of mimics of receptor and catalytic sites of biological macromolecules in the structure of highly cross-linked polymer membranes and thin films. The general strategy for formation of the binding sites in molecularly imprinted polymer (MIP) membranes and thin films was described. A selective recognition of a number of food toxins, endocrine disruptors and metabolites is based on the results of computational modeling data for the prediction and optimization of their structure. A strategy proposed for the design of the artificial binding sites in MIP membranes was supported by the research performed by the authors on development of a number of the MIP membrane-based affinity and catalytic biosensors for selective and sensitive measurement (detection limits 0.3–100 nM) of the target analytes. Novel versatile approaches aimed at improving sensitivity of the developed biosensor systems were discussed.

Relationship of Hearing Loss and Tympanic Membrane Perforation Characteristics in Chronic Suppurative Otitis Media Patients.

Objective The objective of this study is to assess the relationship between the site of tympanic membrane (TM) perforation and the type and degree of hearing impairment. The secondary objectivewas to compare the duration of the disease and the degree of hearing loss. Study design This is a prospective observational study. Place and duration of the study This study was carried out in the Department of Otolaryngology/Head and Neck Surgery at the Pakistan Institute of Medical Sciences, Islamabad, from May 2021 to April 2022. Patients and methods Of all the screened patients, 77 fulfilled the inclusion criteria. Patients aged 10-40 years with inactive mucosal chronic otitis media and unilateral perforation in one quadrant were included. The site of TM rupture was observed, and audiometric analysis was performed. Results The mean age of participants was 25 ± 8.61 years, with a preponderance of the female gender (57.1%). A total of 32 (41.6%), 19 (24.7%), 19 (24.7%), and seven(9.1%) perforations involved posterosuperior, anterosuperior, anteroinferior, and posteroinferior quadrants respectively. Conductive, mixed, and sensorineural hearing loss was found in 52 (67.5%), 18 (23.4%), and seven (9.1%) cases, respectively. Of all the subjects, 13 (16.9%) had the disease for < one year, 39(50.6%) for one to five years, 17 (22.1%) for five to 10 years, and eight (10.4%) for > 10 years. There was a statistically significant association between the degree of hearing loss and the site of perforation. No significant association was found between the site of perforation and thetype of hearing loss. Duration of disease and degree of hearing loss also had no significant association. Conclusion The extent of hearing loss was found to be directly influenced by the anatomical site of perforation, with the posterosuperior quadrant perforation producing the greatest degree of impairment.

Role of endoplasmic reticulum stress in hepatic glucose and lipid metabolism and therapeutic strategies for metabolic liver disease.

The endoplasmic reticulum is the most abundant membrane organelle in eukaryotic cells. It is an important site of membrane and secretory protein folding and glycolipid synthesis and transport, and it is responsible for regulating intracellular calcium homeostasis. When the load of protein synthesis and folding exceeds the processing capacity of the endoplasmic reticulum, the excessive accumulation of misfolded proteins leads to endoplasmic reticulum stress and activates the cellular unfolded protein response. Hepatocytes contain an abundance of smooth and rough endoplasmic reticulum, which can sense changes in various nutritional metabolic and external stimuli and mediate the regulation of glucose and lipid metabolism by activating the unfolded protein response signaling pathways. Endoplasmic reticulum stress plays a very important role in metabolic regulation and in the occurrence and development of liver diseases. This review summarizes the recent research progress on the unfolded protein response and hepatic glucose and lipid metabolism and discusses the mechanism linking endoplasmic reticulum stress with glucose and lipid metabolism disorders and related metabolic liver diseases to improve the understanding of the molecular pathological basis of major chronic diseases such as obesity, type II diabetes and nonalcoholic fatty liver disease.

Dry versus wet temporalis fascia graft in type-I tympanoplasty: a systematic review and meta-analysis of randomized controlled trials.

To conduct a systematic review and meta-analysis of all randomized controlled trials (RCTs) that examined the efficacy of dry versus wet temporalis fascia graft among patients undergoing type-I tympanoplasty. Web of Science, Scopus, PubMed, and CENTRAL databases were screened from inception until July 2022. The Cochrane risk of bias tool was used to assess the quality of included RCTs. The outcomes were summarized as risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI) in a random-effects model. Eight RCTs with 989 patients (dry group = 514 and wet group = 475) were included. The overall quality was 'low', 'some concerns', and 'high' risk of bias in five, two, and one RCT(s), respectively. There were no significant differences between both groups regarding the surgical success rate (n = 8 RCTs, RR 0.99, 95% CI [0.95, 1.03], p = 0.6), audiological success rate (n = 5 RCTs, RR = 0.93, 95% CI [0.73, 1.13], p = 0.48), mean difference in pure tone average (n = 2 RCTs, MD = 2.73Hz, 95% CI [- 2.31, 7.77], p = 0.29), and mean difference in graft placement time (n = 3 RCTs, MD = - 2.18min, 95% CI [- 5.11, 0.76], p = 0.15). However, the mean difference in operative time was significantly lower in favor of the wet compared with the dry temporalis fascia group (n = 2 RCTs, MD = 2.95min, 95% CI [- 1.80, 4.11], p < 0.001). The surgical success rate was not significantly different between both groups according to the tympanic membrane perforation size and site. The type of temporalis fascia graft (dry or wet) did not influence the clinical outcomes of type-I tympanoplasty.

Hearing loss increases with size but not site of tympanic membrane perforation in Aboriginal Australian children in remote locations.

To investigate the effect of size, site, and activity of tympanic membrane (TM) perforation on hearing loss (HL) in Aboriginal and Torres Strait Islander (ATSI) children. Observational study. Children aged 5-18 years who identified as ATSI at seven Anangu community schools within the Anangu Pitjantjatjara Yankunytjatjara Lands and Maralinga Lands of South Australia underwent 4-frequency pure-tone audiometry (0.5, 1, 2, and 4kHz) and video-otoscopy (VO). VO data was reviewed by surgeons for a middle ear diagnosis and VO files with TM perforations were then classified by perforation site (AS, AI, PS, PI, A, P, I) and size (<25%, 25%-50%, 50%-75%, or 75%-100%). Five hundred seventy-five VO files with matching audiological data were obtained. Active perforations (35 dBHL; 28-44 IQR) demonstrated greater HL than inactive perforations (31 dBHL; 29-39 IQR) p=.0029. For inactive perforations there was a significant difference between <25% and all larger perforations (p < .0001) whereas for active perforations the significance changed to between <25% (p < .0001) and 25%-50% (p < .05) when compared to larger perforations. When perforation site was compared within all size/activity groups, no statistically different findings were identified. In all analyses, findings did not change when individual frequencies were compared to 4-frequency pure-tone average dBHL. In ATSI children from remote communities, HL is greater in ears with larger perforations and active middle ear disease but there was no relationship between perforation site and HL.Level of evidence: Level 4.

Individual differences in the positive outcome from adolescent ketamine treatment in a female mouse model of anorexia nervosa involve drebrin A at excitatory synapses of the medial prefrontal cortex.

Anorexia nervosa (AN) is a mental illness with the highest rates of mortality and relapse, and no approved pharmacological treatment. Using an animal model of AN, called activity-based anorexia (ABA), we showed earlier that a single intraperitoneal injection of ketamine at a dose of 30 mg/kg (30mgKET), but not 3 mg/kg (3mgKET), has a long-lasting effect upon adolescent females of ameliorating anorexia-like symptoms through the following changes: enhanced food consumption and body weight; reduced running and anxiety-like behavior. However, there were also individual differences in the drug's efficacy. We hypothesized that individual differences in ketamine's ameliorative effects involve drebrin A, an F-actin-binding protein known to be required for the activity-dependent trafficking of NMDA receptors (NMDARs). We tested this hypothesis by electron microscopic quantifications of drebrin A immunoreactivity at excitatory synapses of pyramidal neurons (PN) and GABAergic interneurons (GABA-IN) in deep layer 1 of prefrontal cortex (PFC) of these mice. Results reveal that (1) the areal density of excitatory synapses on GABA-IN is greater for the 30mgKET group than the 3mgKET group; (2) the proportion of drebrin A+ excitatory synapses is greater for both PN and GABA-IN of 30mgKET than 3mgKET group. Correlation analyses with behavioral measurements revealed that (3) 30mgKET's protection is associated with reduced levels of drebrin A in the cytoplasm of GABA-IN and higher levels at extrasynaptic membranous sites of PN and GABA-IN; (5) altogether pointing to 30mgKET-induced homeostatic plasticity that engages drebrin A at excitatory synapses of both PN and GABA-IN.

DEGREE OF HEARING LOSS IN INACTIVE MUCOSAL CHRONIC OTITIS MEDIA AND ITS CORRELATION WITH SITE AND SIZE OF TYMPANIC MEMBRANE PERFORATION- AN OBSERVATIONAL STUDY

Background: Studies have persistently associated the site and size of the tympanic membrane (TM) with the magnitude of hearing loss;however,the results are mixed and inconclusive on the effect of the site of the perforation on the hearing loss. Therefore, we conducted the present study to investigate the relationship between the size and site of TM perforation and hearing loss in inactive mucosal chronic otitis media. Methods: We conducted a hospital-based observational, prospective study in the Postgraduate Department of Otorhinolaryngology, Head and Neck Surgery, Government Medical College Srinagar, and recruited 94 patients diagnosed to have inactive mucosal chronic otitis media with dry tympanic membrane perforation. In addition to the site and size of TM perforation, the magnitude of hearing loss was also estimated. Results: We recruited 94 subjects presenting acute otitis media with TP perforation. The mean age (±SD) of cases was 36.3(±4) and males showed a marginal over-representation over females (male to female ratio: 1.2:1). We observed a positive correlation of the size of TM perforation with the average hearing loss. Moreover, subjects having perforations in the posterior ear reported higher average hearing loss. Conclusion: We report a positive correlation of the size of TM perforation with the average hearing loss and subjects having perforations in the posterior ear reported higher average hearing loss. However, more replicative studies with a larger sample size are warranted to substantiate our findings.

Fabrication of the polyethersulfone/functionalized mesoporous carbon nanocomposite nanofiltration membrane for dyes and heavy metal ions removal: Experimental and quantum mechanical simulation method

AbstractThe presence of industrial pollutants, especially salts, heavy metals ions, and dyes in water and wastewater is considered a serious environmental issue. To eliminate these pollutants, a high‐performing nanofiltration (NF) membrane was prepared by blending the functionalized mesoporous carbon CMK‐5 (F‐CMK‐5) nanofiller. This membrane was synthesized by introducing the active groups of sulfonyl and amide to the surface of mesoporous carbon CMK‐5 through covalent functionalization. Characterizations were conducted to study the membranes' physical properties and separation performance in terms of antifouling properties and rejection of salts, heavy metal ions, and dyes. The interactions between the active sites of the nanocomposite membrane and the studied solutes, including dyes and heavy metal ions in aqueous solutions, were studied by the density functional based tight binding method and structural optimization was carried out. Insertion of the F‐CMK‐5 nanofiller was eventuated in a remarkable increase in surface hydrophilicity, pure water flux, and antifouling properties. For all membranes, the lowest and the highest salt rejection was obtained for NaCl and Na2SO4, respectively, exhibiting the characteristics of NF membranes. Moreover, M0.3 with 0.3 wt% nanofiller showed the highest rejection for heavy metal ions (Fe2+ = 99.9%, Zn2+ = 99.9%, Cu2+ = 99.7%, and Pb2+ = 99.2%) and dyes (RB5 = 99.21, DR16 = 98.87, and MB = 98.12%), as well as high separation performance for filtration of multipollutant solutions. The reusability and 144 h uninterrupted filtration experiments for M0.3 confirmed the stability of the membrane. The findings suggest that the PES/F‐CMK‐5 nanocomposite NF membrane is a promising candidate for water and wastewater treatment.

Surface cholesterol-enriched domains specifically promote invasion of breast cancer cell lines by controlling invadopodia and extracellular matrix degradation

Tumor cells exhibit altered cholesterol content. However, cholesterol structural subcellular distribution and implication in cancer cell invasion are poorly understood mainly due to difficulties to investigate cholesterol both quantitatively and qualitatively and to compare isogenic cell models. Here, using the MCF10A cell line series (non-tumorigenic MCF10A, pre-malignant MCF10AT and malignant MCF10CAIa cells) as a model of breast cancer progression and the highly invasive MDA-MB-231 cell line which exhibits the common TP53 mutation, we investigated if cholesterol contributes to cancer cell invasion, whether the effects are specific to cancer cells and the underlying mechanism. We found that partial membrane cholesterol depletion specifically and reversibly decreased invasion of the malignant cell lines. Those cells exhibited dorsal surface cholesterol-enriched submicrometric domains and narrow ER-plasma membrane and ER-intracellular organelles contact sites. Dorsal cholesterol-enriched domains can be endocytosed and reach the cell ventral face where they were involved in invadopodia formation and extracellular matrix degradation. In contrast, non-malignant cells showed low cell invasion, low surface cholesterol exposure and cholesterol-dependent focal adhesions. The differential cholesterol distribution and role in breast cancer cell invasion provide new clues for the understanding of the molecular events underlying cellular mechanisms in breast cancer.

Competitive interaction of Mn(II) and Fe(II) cations with the high-affinity Mn-binding site of the photosystem II: evolutionary aspect.

The evolutionary origin of the oxygen-evolving complex (OEC) in the photosystem II (PSII) is still unclear, as is the nature of electron source for the photosystem before the OEC had appeared. Johnson et al. (in PNAS 110:11238, 2013) speculated that Mn(II) cations were the source of electrons for transitional photosystems. However, Archean oceans also contained Fe(II) cations at concentrations comparable or higher than that of Mn(II). Fe(II) cations can bind to the high-affinity (НА) Mn-binding site in the OEC (Semin et al. in Biochemistry 41:5854, 2002). Now we have investigated the competitive interaction of Mn(II) and Fe(II) cations with the HA site in the Mn-depleted PSII membranes (PSII[-Mn]). Fe cations, oxidized under illumination, bind strongly to the HA site and, thus, prevent the interaction of Mn(II) with this site. If the Mn(II) and Fe(II) cations, at relatively equal concentration, are simultaneously present in the buffer, together with PSII(-Mn) membranes, there is competition between these two cations for the binding site, which manifests itself in partial inhibition of the Mn(II) oxidation and the blocking of the HA site by Fe(II) cations. If the concentration of Fe(II) cations is several times higher than the concentration of Mn(II), the HA site is completely blocked and the oxidation of Mn(II) cations is inhibited; under saturating light, the effectiveness of this inhibitory effect increases. This may be due to the generation of H2O2 on the acceptor side of the photosystem, which significantly accelerates the rate of the turnover reaction of Mn(II) on the HA site.

An efficient and high-capacity porous functionalized-membranes for uranium recovery from wastewater

In order to satisfy the increasing needs for sustainable development of the nuclear energy industry, it is critical to vigorously develop efficient materials for uranium separation and recovery from wastewater. In this work, novel amidoxime-functionalized membranes (PAO membranes) were successfully synthesized via a facile one-step non-solvent induce phase separation rather than as-reported synthesized approaches that needed complicated additives or harsh reaction conditions. The pore channels provided large specific surface areas and massive binding sites, and the bulk-shape membrane was convenient for collection. Removal of uranium as a function of initial pH, reaction time, initial concentrations of U(VI), and temperature was studied. The maximum adsorption capacity of the PAO membranes toward U(VI) calculated from the Langmuir model was up to 641.72 mg·g−1 at pH 5 and 298 K. Thermodynamic studies indicated that the enrichment of U(VI) was a spontaneous and endothermic process. The removal percentage of uranium reached 86.50% in simulated wastewater in the case of multiple coexisting metal ions. In addition, the scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results confirmed that the abundant adsorption sites of the PAO membranes were responsible for the efficient immobilization of uranium by forming chelating species, especially amidoxime groups and carboxyl groups. This work presents a novel strategy for mass production of a new generation of high-efficiency adsorbents for uranium-containing wastewater treatment in the future.

Synergism of orderly intrinsic and extrinsic proton-conducting sites in covalent organic framework membranes

Development of high proton-conducting membranes is the major demand in energy conversion, sensing, and catalysis. The emerging ionic covalent organic frameworks (iCOFs) with abundant and well-arranged proton-conducting groups offer new materials for efficient proton conduction. However, the poor processability of iCOFs makes it difficult to fabricate defect-free membranes. Herein, we use the interfacial reaction method to synthesize high crystalline iCOF nanosheets (NUS-9) which are then processed into defect-free membranes by vacuum-assisted assembly method. The plenty of intrinsic orderly aligned sulfonic acid groups in the iCOF skeletons endows the nanosheets with intrinsic high proton conductivity. Furthermore, the deoxyribonucleic acid molecules (DNA) with sequential linear arranged phosphate groups are intercalated into the iCOF membrane. The synergetic effect of orderly intrinsic and extrinsic proton-conducting sites gives the resulting DNA@iCOF membranes high proton conductivity of up to 494.7 mS cm−1 (98% RH, 80 °C), which is among the highest values of the state-of-the-art COF-based proton conductors. Besides, it also retains high conductivity over a wide range of RH (40–100%) and temperature (30−80 °C).

Phospholipase D1-generated phosphatidic acid modulates secretory granule trafficking from biogenesis to compensatory endocytosis in neuroendocrine cells.

Calcium-regulated exocytosis is a multi-step process that allows specialized secretory cells to release informative molecules such as neurotransmitters, neuropeptides, and hormones for intercellular communication. The biogenesis of secretory vesicles from the Golgi cisternae is followed by their transport towards the cell periphery and their docking and fusion to the exocytic sites of the plasma membrane allowing release of vesicular content. Subsequent compensatory endocytosis of the protein and lipidic constituents of the vesicles maintains cell homeostasis. Despite the fact that lipids represent the majority of membrane constituents, little is known about their contribution to these processes. Using a combination of electrochemical measurement of single chromaffin cell catecholamine secretion and electron microscopy of roof-top membrane sheets associated with genetic, silencing and pharmacological approaches, we recently reported that diverse phosphatidic acid (PA) species regulates catecholamine release efficiency by controlling granule docking and fusion kinetics. The enzyme phospholipase D1 (PLD1), producing PA from phosphatidylcholine, seems to be the major responsible of these effects in this model. Here, we extended this work using spinning disk confocal microscopy showing that inhibition of PLD activity also reduced the velocity of granules undergoing a directed motion. Furthermore, a dopamine β-hydroxylase (DβH) internalization assay revealed that PA produced by PLD is required for an optimal recovery of vesicular membrane content by compensatory endocytosis. Thus, among numerous roles that have been attributed to PA our work gives core to the key regulatory role in secretion that has been proposed in different cell models. Few leads to explain these multiple functions of PA along the secretory pathway are discussed.

Enteric Glia and Enteric Neurons, Associated.

Peripheral neurons are never found alone and are invariably accompanied by glial cells, with which they are intimately associated in compact, highly deformable structures.Myenteric ganglia of the guinea-pig, examined in situ by electron microscopy, show that in their neuropil (axons and dendrites, and glial cells and processes) the glia constitutes almost half of the volume and almost half of membrane extent.In the glia, the expanse of the cell membrane predominates over that of their cytoplasm, the opposite being the case with the neural elements.The profile of the glial elements is passive and is dictated by the surrounding elements, mainly the axons, and hence it is predominantly concave.The enteric glia is widely developed; however, it is not sufficient to form a full wrapping around all neurons and around all axons (unlike what is found in other autonomic ganglia).Glial processes are radially expanding laminae, irregularly tapering, branching, and penetrating between axons.Some processes have a specialized termination attached to the basal lamina of the ganglion.Mitochondria are markedly more abundant in neural element that in the glia (up to a factor of 2).Many expanded axons, laden with vesicles clustered beneath membrane sites, abut on glial cells and processes, while these show no matching structural specializations.

Detection of superoxide radical in all biological systems by Thin Layer Chromatography

The study presents a new method that detects O2•−, via quantification of 2-hydroxyethidium (2-ΟΗ-Ε+) as low as ∼30 fmoles by High-Performance Thin Layer Chromatography (HPTLC). The method isolates 2-ΟΗ-Ε+ after its extraction by the anionic detergent SDS (at 18-fold higher than its CMC) together with certain organic/inorganic reagents, and its HPTLC-separation from di-ethidium (di-Ε+) and ethidium (Ε+). Quantification of 2-OH-E+ is based on its ex/em maxima at 290/540 nm, and of di-E+ and E+ at 295/545 nm. The major innovations of the present method are the development of protocols for (i) efficient extraction (by SDS) and (ii) sensitive quantification (by HPTLC) for 2-OH-E+ (as well as di-E+ and E+) from most biological systems (animals, plants, cells, subcellular compartments, fluids). The method extracts 2-ΟΗ-Ε+ (by neutralizing the strong binding between its quaternary N+ and negatively charged sites on phospholipids, DNA etc) together with free HE, while protects both from biological oxidases, and also extracts/quantifies total proteins (hydrophilic and hydrophobic) for expressing O2•− levels per protein quantity. The method also uses SDS (at 80-fold lower than its CMC) to extract/remove/wash 2-ΟΗ-Ε+ from cell/organelle exterior membrane sites, for more accurate internal content quantification. The new method is applied on indicative biological systems: (1) artificially stressed (mouse organs and liver mitochondria and nuclei, ±exposed to paraquat, a known O2•− generator), and (2) physiologically stressed (cauliflower plant, exposed to light/dark).

Cell membrane-anchored anti-HIV single-chain antibodies and bifunctional inhibitors targeting the gp41 fusion protein: new strategies for HIV gene therapy

ABSTRACT Emerging studies indicate that infusion of HIV-resistant cells could be an effective strategy to achieve a sterilizing or functional cure. We recently reported that glycosylphosphatidylinositol (GPI)-anchored nanobody or a fusion inhibitory peptide can render modified cells resistant to HIV-1 infection. In this study, we comprehensively characterized a panel of newly isolated HIV-1-neutralizing antibodies as GPI-anchored inhibitors. Fusion genes encoding the single-chain variable fragment (scFv) of 3BNC117, N6, PGT126, PGT128, 10E8, or 35O22 were constructed with a self-inactivating lentiviral vector, and they were efficiently expressed in the lipid raft sites of target cell membrane without affecting the expression of HIV-1 receptors (CD4, CCR5 and CXCR4). Significantly, transduced cells exhibited various degrees of resistance to cell-free HIV-1 infection and cell-associated HIV-1 transmission, as well as viral Env-mediated cell–cell fusion, with the cells modified by GPI-10E8 showing the most potent and broad anti-HIV activity. In mechanism, GPI-10E8 also interfered with the processing of viral Env in transduced cells and attenuated the infectivity of progeny viruses. By genetically linking 10E8 with a fusion inhibitor peptide, we subsequently designed a group of eight bifunctional constructs as cell membrane-based inhibitors, designated CMI01∼CMI08, which rendered cells completely resistant to HIV-1, HIV-2, and simian immunodeficiency virus (SIV). In human CD4+ T cells, GPI-10E8 and its bifunctional derivatives blocked both CCR5- and CXCR4-tropic HIV-1 isolates efficiently, and the modified cells displayed robust survival selection under HIV-1 infection. Therefore, our studies provide new strategies for generating HIV-resistant cells, which can be used alone or with other gene therapy approaches.

Roles of matrix metalloproteinases in development, immunology, and ovulation in fruit Fly (Drosophila).

Matrix metalloproteinase (MMP), a protease enzyme, participates in proteolytic cleavage of extracellular matrix proteins from Drosophila and mammals. But, recent studies have revealed other physiologically important roles of MMP in Drosophila. MMP contributes to cardioblast movement and distribution of collagen proteins during cardiogenesis in developing Drosophila. Tissue remodeling, especially tracheal development is also maintained by MMP. MMP regulates certain immunological functions in Drosophila such as wound repairing, plasmatocyte assemblage at the injured site of the basement membrane and glial response to axon degeneration in Drosophila nervous system. But, the contribution of MMP to tumor formation and metastasis in Drosophila has made it an interesting topic among researchers. Ovulation and egg laying are also found to be affected positively by MMP in Drosophila.

Small-Sized Co-Polymers for Targeted Delivery of Multiple Imaging and Therapeutic Agents

Research has increasingly focused on the delivery of high, often excessive amounts of drugs, neglecting negative aspects of the carrier’s physical preconditions and biocompatibility. Among them, little attention has been paid to “small but beautiful” design of vehicle and multiple cargo to achieve effortless targeted delivery into deep tissue. The design of small biopolymers for deep tissue targeted delivery of multiple imaging agents and therapeutics (mini-nano carriers) emphasizes linear flexible polymer platforms with a hydrodynamic diameter of 4 nm to 10 nm, geometrically favoring dynamic juxtaposition of ligands to host receptors, and economic drug content. Platforms of biodegradable, non-toxic poly(β-l-malic acid) of this size carrying multiple chemically bound, optionally nature-derived or synthetic affinity peptides and drugs for a variety of purposes are described in this review with specific examples. The size, shape, and multiple attachments to membrane sites accelerate vascular escape and fast blood clearance, as well as the increase in medical treatment and contrasts for tissue imaging. High affinity antibodies routinely considered for targeting, such as the brain through the blood–brain barrier (BBB), are replaced by moderate affinity binding peptides (vectors), which penetrate at high influxes not achievable by antibodies.