Mixed oxide nanotubes in nanomedicine: A dead-end or a bridge to the future?

Nanomedicine has seen a significant rise in the development of new research tools and clinically functional devices. In this regard, significant advances and new commercial applications are expected in the pharmaceutical and orthopedic industries. For advanced orthopedic implant technologies, appropriate nanoscale surface modifications are highly effective strategies and are widely studied in the literature for improving implant performance. It is well-established that implants with nanotubular surfaces show a drastic improvement in new bone creation and gene expression compared to implants without nanotopography. Nevertheless, the scientific and clinical understanding of mixed oxide nanotubes (MONs) and their potential applications, especially in biomedical applications are still in the early stages of development. This review aims to establish a credible platform for the current and future roles of MONs in nanomedicine, particularly in advanced orthopedic implants. We first introduce the concept of MONs and then discuss the preparation strategies. This is followed by a review of the recent advancement of MONs in biomedical applications, including mineralization abilities, biocompatibility, antibacterial activity, cell culture, and animal testing, as well as clinical possibilities. To conclude, we propose that the combination of nanotubular surface modification with incorporating sensor allows clinicians to precisely record patient data as a critical contributor to evidence-based medicine.

Synthesis of sharply thermo and PH responsive PMA-b-PNIPAM-b-PEG-b-PNIPAM-b-PMA by RAFT radical polymerization and its schizophrenic micellization in aqueous solutions.

Sharply thermo- and pH-responsive pentablock terpolymer with a core-shell-corona structure was prepared by RAFT polymerization of N-isopropylacrylamide and methacrylic acid monomers using PEG-based benzoate-type of RAFT agent. The PEG-based RAFT agent could be easily synthesized by dihydroxyl-capped PEG with 4-cyano-4-(thiobenzoyl) sulfanylpentanoic acids, using esterification reaction. This pentablock terpolymer was characterized by 1H NMR, FT-IR, and GPC. The PDI was obtained by GPC, indicating that the molecular weight distribution was narrow and the polymerization was well controlled. The thermo- and pH-responsive micellization of the pentablock terpolymer in aqueous solution was investigated using fluorescence spectroscopy technique, UV-vis transmittance, and TEM. The LCST of pentablock terpolymer increased (over 50 °C) compared to the NIPAM homopolymer (~32 °C), due to the incorporation of the hydrophilic PEG and PMA blocks in pentablock terpolymer (PNIPAM block as the core, PEG the block and the hydrophilic PMA block as the shell and the corona). Also, pH-dependent phase transition behavior shows at a pH value of about ~5.8, according to pKa of MAA. Thus, in acidic solution at room temperature, the pentablock terpolymer self-assembled to form core-shell-corona micelles, with the hydrophobic PMA block as the core, the PNIPAM block and the hydrophilic PEG block as the shell and the corona, respectively.

Anthelmintic PF1022A: stepwise solid-phase synthesis of a cyclodepsipeptide containing N-methyl amino acids.

Cyclodepsipeptides of the enniation-, PF1022-, and verticilide-family represent a diverse class of highly interesting natural products with respect to their manifold biological activities. However, until now no stepwise solid-phase synthesis has been accomplished due to the difficult combination of N-methyl amino acids and hydroxycarboxylic acids. We report here the first stepwise solid-phase synthesis of the anthelmintic cyclooctadepsipeptide PF1022A based on an Fmoc/THP-ether protecting group strategy on Wang-resin. The standard conditions of our synthesis allow an unproblematic adaption to an automated peptide synthesizer.

Continuous microfluidic synthesis of zirconium-based UiO-67 using a coiled flow invertor reactor.

Metal-organic frameworks (MOFs), particularly Zirconium based, have a wide variety of potential applications, such as catalysis and separation. However, these are held back by traditionally only being synthesised in long batch reactions, which causes the process to be expensive and limit the amount of reaction control available, leading to potential batch to batch variation in the products, such as particle size distributions. Microfluidics allows for batch reactions to be performed with enhanced mass/heat transfer, with the coiled flow inverter reactor (CFIR) setup narrowing the residence time distribution, which is key in controlling the particle size and crystallinity. In this work, a Zirconium based MOF, UiO-67, has been synthesised continuously using a microfluidic CFIR, which has allowed for the product to be formed in 30 min, a fraction of the traditional batch heating time of 24 h. The microfluidicially synthesised UiO-67 is also smaller product with a narrower particle size distribution (≈200 nm to ≈400 nm) than its batch counterpart (~500 nm to over 3 µm).

Uptake and trafficking of different sized PLGA nanoparticles by dendritic cells in imiquimod-induced psoriasis-like mice model.

Psoriasis is an autoimmune inflammatory disease, where dendritic cells (DCs) play an important role in its pathogenesis. In our previous work, we have demonstrated that topical delivery of curcumin-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) could treat Imiquimod (IMQ)-induced psoriasis-like mice. The objective of this study is to further elucidate biofate of PLGA NPs after intradermal delivery including DCs uptake, and their further trafficking in psoriasis-like mice model by using fluorescence probes. Two-sized DiO/DiI-loaded PLGA NPs of 50 ± 4.9 nm (S-NPs) and 226 ± 7.8 nm (L-NPs) were fabricated, respectively. In vitro cellular uptake results showed that NPs could be internalized into DCs with intact form, and DCs preferred to uptake larger NPs. Consistently, in vivo study showed that L-NPs were more captured by DCs and NPs were firstly transported to skin-draining lymph nodes (SDLN), then to spleens after 8 h injection, whereas more S-NPs were transported into SDLN and spleens. Moreover, FRET imaging showed more structurally intact L-NPs distributed in skins and lymph nodes. In conclusion, particle size can affect the uptake and trafficking of NPs by DCs in skin and lymphoid system, which needs to be considered in NPs tailing to treat inflammatory skin disease like psoriasis.

Facile synthesis of insulin fusion derivatives through sortase A ligation.

Insulin derivatives such as insulin detemir and insulin degludec are U.S. Food and Drug Administration (FDA)-approved long-acting insulin currently used by millions of people with diabetes. These derivatives are modified in C-terminal B29 lysine to retain insulin bioactivity. New and efficient methods for facile synthesis of insulin derivatives may lead to new discovery of therapeutic insulin. Herein, we report a new method using sortase A (SrtA)-mediated ligation for the synthesis of insulin derivatives with high efficiency and functional group tolerance in the C-terminal B chain. This new insulin molecule (Ins-SA) with an SrtA-recognizing motif can be conjugated to diverse groups with N-terminal oligoglycines to generate new insulin derivatives. We further demonstrated that a new insulin derivative synthesized by this SrtA-mediated ligation shows strong cellular and in vivo bioactivity. This enzymatic method can therefore be used for future insulin design and development.

Evodiamine-inspired dual inhibitors of histone deacetylase 1 (HDAC1) and topoisomerase 2 (TOP2) with potent antitumor activity.

A great challenge in multi-targeting drug discovery is to identify drug-like lead compounds with therapeutic advantages over single target inhibitors and drug combinations. Inspired by our previous efforts in designing antitumor evodiamine derivatives, herein selective histone deacetylase 1 (HDAC1) and topoisomerase 2 (TOP2) dual inhibitors were successfully identified, which showed potent in vitro and in vivo antitumor potency. Particularly, compound 30a was orally active and possessed excellent in vivo antitumor activity in the HCT116 xenograft model (TGI = 75.2%, 150 mg/kg, p.o.) without significant toxicity, which was more potent than HDAC inhibitor vorinostat, TOP inhibitor evodiamine and their combination. Taken together, this study highlights the therapeutic advantages of evodiamine-based HDAC1/TOP2 dual inhibitors and provides valuable leads for the development of novel multi-targeting antitumor agents.

First small-molecule PROTACs for G protein-coupled receptors: inducing α 1A-adrenergic receptor degradation.

Proteolysis targeting chimeras (PROTACs) are dual-functional hybrid molecules that can selectively recruit an E3 ubiquitin ligase to a target protein to direct the protein into the ubiquitin-proteasome system (UPS), thereby selectively reducing the target protein level by the ubiquitin-proteasome pathway. Nowadays, small-molecule PROTACs are gaining popularity as tools to degrade pathogenic protein. Herein, we present the first small-molecule PROTACs that can induce the α 1A-adrenergic receptor (α 1A-AR) degradation, which is also the first small-molecule PROTACs for G protein-coupled receptors (GPCRs) to our knowledge. These degradation inducers were developed through conjugation of known α 1-adrenergic receptors (α 1-ARs) inhibitor prazosin and cereblon (CRBN) ligand pomalidomide through the different linkers. The representative compound 9c is proved to inhibit the proliferation of PC-3 cells and result in tumor growth regression, which highlighted the potential of our study as a new therapeutic strategy for prostate cancer.

An overview on medicinal perspective of thiazolidine-2,4-dione: A remarkable scaffold in the treatment of type 2 diabetes.

Diabetes or diabetes mellitus is a complex or polygenic disorder, which is characterized by increased levels of glucose (hyperglycemia) and deficiency in insulin secretion or resistance to insulin over an elongated period in the liver and peripheral tissues. Thiazolidine-2,4-dione (TZD) is a privileged scaffold and an outstanding heterocyclic moiety in the field of drug discovery, which provides various opportunities in exploring this moiety as an antidiabetic agent. In the past few years, various novel synthetic approaches had been undertaken to synthesize different derivatives to explore them as more potent antidiabetic agents with devoid of side effects (i.e., edema, weight gain, and bladder cancer) of clinically used TZD (pioglitazone and rosiglitazone). In this review, an effort has been made to summarize the up to date research work of various synthetic strategies for TZD derivatives as well as their biological significance and clinical studies of TZDs in combination with other category as antidiabetic agents. This review also highlights the structure-activity relationships and the molecular docking studies to convey the interaction of various synthesized novel derivatives with its receptor site.

Cold-active extracellular lipase: Expression in Sf9 insect cells, purification, and catalysis.

Cold-active lipases are gaining special attention nowadays as they are increasingly used in various industries such as fine chemical synthesis, food processing, and washer detergent. In the present study, an extracellular lipase gene from Yarrowia lipolytica (LIPY8) was cloned and expressed by baculovirus expression system. The recombinant lipase (LipY8p) was purified using chromatographic techniques, resulting in a purification factor of 25.7-fold with a specific activity of 1102.9U/mg toward olive oil. The apparent molecular mass of purified LipY8p was 40 kDa. The enzyme was most active at pH 7.5 and 17 °C. It exhibited maximum activity toward medium chain (C10) esters. The presence of transition metals such as Zn2+, Cu2+, and Ni2+ strongly inhibited the enzyme activity, which was enhanced by EDTA. The lipase activity was affected by detergents and was elevated by various organic solvents at 10% (v/v). These enzymatic properties make this lipase of considerable potential for biotechnological applications.

Biomimetic thiamine- and niacin-decorated liposomes for enhanced oral delivery of insulin.

Biomimetic nanocarriers are emerging as efficient vehicles to facilitate dietary absorption of biomacromolecules. In this study, two vitamins, thiamine and niacin, are employed to decorate liposomes loaded with insulin, thus facilitating oral absorption via vitamin ligand-receptor interactions. Both vitamins are conjugated with stearamine, which works to anchor the ligands to the surface of liposomes. Liposomes prepared under optimum conditions have a mean particle size of 125-150 nm and an insulin entrapment efficiency of approximately 30%-36%. Encapsulation into liposomes helps to stabilize insulin due to improved resistance against enzymatic disruption, with 60% and 80% of the insulin left after 4 h when incubated in simulated gastric and intestinal fluids, respectively, whereas non-encapsulated insulin is broken down completely at 0.5 h. Preservation of insulin bioactivity against preparative stresses is validated by intra-peritoneal injection of insulin after release from various liposomes using the surfactant Triton X-100. In a diabetic rat model chemically induced by streptozotocin, both thiamine- and niacin-decorated liposomes showed a comparable and sustained mild hypoglycemic effect. The superiority of decorated liposomes over conventional liposomes highlights the contribution of vitamin ligands. It is concluded that decoration of liposomes with thiamine or niacin facilitates interactions with gastrointestinal vitamin receptors and thereby facilitates oral absorption of insulin-loaded liposomes.

Multiple exo-glycosidases in human serum as detected with the substrate DNP-α-GalNAc. I. A new assay for lysosomal α-N-acetylgalactosaminidase.

This paper presents a new assay to determine the activity of the lysosomal enzyme α-N-acetylgalactosaminidase (Naga, EC 3.2.1.49) in human serum. It is based on the use of a new chromogenic substrate, DNP-α-GalNAc (2,4-dinitrophenyl-N-acetyl-α-D-galactosaminide) and is performed at pH 4.3 and 37 °C. This allows continuous monitoring of the absorbance of the released DNP. The assay can be performed with a standard spectrophotometer. Compared to established methods using an endpoint assay with MU-α-GalNAc (4-methylumbelliferyl-GalNAc), the present method gives a ca. 3-fold higher specific activity, while only one tenth of the serum concentration in the assay is required. Hence, the assay is at least 30-fold more sensitive than that with MU-α-GalNAc. The pH dependence of the reaction with DNP-α-GalNAc in the pH 3.5 to 6.5 region, while using 4% serum in the assay, shows only one peak around pH 4. This pH optimum is similar to that reported with MU-α-GalNAc. In the accompanying paper (Albracht and Van Pelt (2017) Multiple exo-glycosidases in human serum as detected with the substrate DNP-α-GalNAc. II. Three α-N-acetylgalactosaminidase-like activities in the pH 5 to 8 region. Biochim. Biophys. Acta 159 (2017) Part I and II), the method is used to show that, under special assay conditions, three more Naga-like activities can be uncovered in human serum.

Multiple exo-glycosidases in human serum as detected with the substrate DNP-α-GalNAc. II. Three α-N-acetylgalactosaminidase-like activities in the pH 5 to 8 region.

With the substrate DNP-α-GalNAc (2,4-dinitrophenyl-N-acetyl-α-d-galactosaminide) three α-N-acetylgalactosaminidase-like activities could be distinguished in serum, in addition to the classical lysosomal enzyme (Naga, EC 3.2.1.49, pH optimum at 4). Two activities had optima in the pH 5 to 6 region and one peaked around pH 8. Like the Naga activity at pH 4, the activity at pH 8 was detectable under standard assay conditions. However, the two activities in the pH 5 to 6 range were not readily apparent in such assays. They could be unmasked as separate activities only when low serum concentrations were used. Addition of 1% saturated ammonium sulphate to the assay medium stimulated these activities. All activities in the pH 5 to 8 range decreased with increasing serum concentration in the assay, suggesting the presence of endogenous inhibitors. The activities between pH 5 and 6 might be similar to an activity described in 1996, which was considerably elevated in serum of patients with great variety of cancers (N. Yamamoto, V.R. Naraparaju, and S.O. Asbell (1996). Deglycosylation of serum vitamin D3-binding protein leads to immunosuppression in cancer patients. Cancer Res. 56, 2827-2811).

Uptake and trafficking of different sized PLGA nanoparticles by dendritic cells in imiquimod-induced psoriasis-like mice model

Psoriasis is an autoimmune inflammatory disease, where dendritic cells (DCs) play an important role in its pathogenesis. In our previous work, we have demonstrated that topical delivery of curcumin-loaded poly (lactic-

Substrate specificity of mitochondrial intermediate peptidase analysed by a support-bound peptide library.

The substrate specificity of recombinant human mitochondrial intermediate peptidase (hMIP) using a synthetic support-bound FRET peptide library is presented. The collected fluorescent beads, which contained the hydrolysed peptides generated by hMIP, were sequenced by Edman degradation. The results showed that this peptidase presents a remarkable preference for polar uncharged residues at P1 and P1' substrate positions: Ser = Gln > Thr at P1 and Ser > Thr at P1'. Non-polar residues were frequent at the substrate P3, P2, P2' and P3' positions. Analysis of the predicted MIP processing sites in imported mitochondrial matrix proteins shows these cleavages indeed occur between polar uncharged residues. Previous analysis of these processing sites indicated the importance of positions far from the MIP cleavage site, namely the presence of a hydrophobic residue (Phe or Leu) at P8 and a polar uncharged residue (Ser or Thr) at P5. To evaluate this, additional kinetic analyses were carried out, using fluorogenic substrates synthesized based on the processing sites attributed to MIP. The results described here underscore the importance of the P1 and P1' substrate positions for the hydrolytic activity of hMIP. The information presented in this work will help in the design of new substrate-based inhibitors for this peptidase.

Selective targeting of the IL23 pathway: Generation and characterization of a novel high-affinity humanized anti-IL23A antibody.

Herein, we describe the generation and characterization of BI 655066, a novel, highly potent neutralizing anti-interleukin-23 (IL23) monoclonal antibody in clinical development for autoimmune conditions, including psoriasis and Crohn's disease. IL23 is a key driver of the differentiation, maintenance, and activity of a number of immune cell subsets, including T helper 17 (Th17) cells, which are believed to mediate the pathogenesis of several immune-mediated disorders. Thus, IL23 neutralization is an attractive therapeutic approach. Designing an antibody for clinical activity and convenience for the patient requires certain properties, such as high affinity, specificity, and solubility. These properties were achieved by directed design of the immunization, lead identification, and humanization procedures. Favorable substance and pharmacokinetic properties were established by biophysical assessments and studies in cynomolgus monkeys.