Synthesis of mannose-6-phosphate analogues and their utility as angiogenesis regulators

Could CH3-M6P Be a Potential Dual-Functioning Candidate for Bone Regeneration?

Background: CI-RM6P has different binding sites with affinities for both M6P and IGF2, plays a role in the regulation of the TGF-β and IGF pathways that is important for controlling cell growth and differentiation. We hypothesize that previously synthesised derivative of M6P could be an alternative candidate for bone tissue regeneration in terms of higher binding affinity, stability in human serum, low cost and temporal delivery. Methods: CH3-M6P is synthesised based on previously described protocol; mesenchymal origin of isolated DPSCs was assessed by flow cytometry and AR staining prior to alkaline phosphatase (ALP) activity test, qPCR to evaluate differentiation specific marker expression, immunofluoresence, and SEM/EDS to evaluate organic and inorganic matrix formation; and rat aortic ring model to evaluate angiogenic effect of molecule. Results: CH3-M6P upregulated ALP activity, the expression of the ALP, Col1, RunX2, Mef2C, TGFβ1, TGFβ1R, TGFβ2, and Smad3 genes under osteogenic conditions. The results of immunofluorescence and SEM/EDS studies did not show enhancing effect on matrix formation. As we observed, the induction effect of CH3-M6P on the expression of angiogenic genes such as SMAD3 and TGFβ1R, even under osteogenic conditions, within the scope of research, we checked the angiogenic effect of the molecule and compared it to VEGF, showing that the CH3-M6P is really angiogenic. Conclusions: Our findings provide an important clue for the further exploration of the molecule, which can be necessary to enhance the capability of the commonly used osteomedium, possibly leading to the development of bone-forming drugs and has the potential to be a dual-functioning molecule for bone tissue engineering.

Exploring the impact of severity in hepatic fibrosis disease on the intrahepatic distribution of novel biodegradable nanoparticles targeted towards different disease biomarkers

Nanoparticle-based drug delivery systems (DDS) have shown promising results in reversing hepatic fibrosis, a common pathological basis of chronic liver diseases (CLDs), in preclinical animal models. However, none of these nanoparticle formulations has transitioned to clinical usage and there are currently no FDA-approved drugs available for liver fibrosis. This highlights the need for a better understanding of the challenges faced by nanoparticles in this complex disease setting. Here, we have systematically studied the impact of targeting strategy, the degree of macrophage infiltration during fibrosis, and the severity of fibrosis, on the liver uptake and intrahepatic distribution of nanocarriers. When tested in mice with advanced liver fibrosis, we demonstrated that the targeting ligand density plays a significant role in determining the uptake and retention of the nanoparticles in the fibrotic liver whilst the type of targeting ligand modulates the trafficking of these nanoparticles into the cell population of interest - activated hepatic stellate cells (aHSCs). Engineering the targeting strategy indeed reduced the uptake of nanoparticles in typical mononuclear phagocyte (MPS) cell populations, but not the infiltrated macrophages. Meanwhile, additional functionalization may be required to enhance the efficacy of DDS in end-stage fibrosis/cirrhosis compared to early stages.

One-pot Dess-Martin periodinane-mediated oxidative deprotection and olefination of trimethylsilyl-protected pyranosides and pyranoses

The selective functionalization of carbohydrates provides a powerful method for introducing structural complexity, allowing access to unique drug scaffolds with distinctive pharmaceutical profiles. Herein, we describe an efficient and selective carbon-carbon bond forming reaction of a variety of common trimethylsilyl-protected pyranosides and pyranoses at C-6 using a one-pot Dess-Martin periodinane-mediated oxidation deprotection. This is followed by addition of stabilized and non-stabilized ylides to generate alkenoate carbohydrates and related analogs in good to moderate yields. We also report on the rapid deprotection of the remaining trimethylsilyl ether groups in near quantitative yields using an acidic resin-mediated ethanolysis.

The Angiogenic Balance and Its Implications in Cancer and Cardiovascular Diseases: An Overview

Angiogenesis is the process of developing new blood vessels from pre-existing ones. This review summarizes the main features of physiological and pathological angiogenesis and those of angiogenesis activation and inhibition. In healthy adults, angiogenesis is absent apart from its involvement in female reproductive functions and tissue regeneration. Angiogenesis is a complex process regulated by the action of specific activators and inhibitors. In certain diseases, modulating the angiogenic balance can be a therapeutic route, either by inhibiting angiogenesis (for example in the case of tumor angiogenesis), or by trying to activate the process of new blood vessels formation, which is the goal in case of cardiac or peripheral ischemia.

Pathways in the synthesis of functionalized glycolipids for liposomal preparations

We describe in this paper the synthesis of two glycolipids containing a mannosyl residue functionalized with malonic acid and azide groups at the C6 position. Two synthetic routes have been successfully implemented: the first one involves Schmidt's glycosylation procedure using functionalized carbohydrates, whereas the second one involves nucleophilic substitutions in the C6 position of an iodinated intermediate obtained using Koenigs-Knorr reaction. A comparative discussion of reactions and yields is realized. The two glycolipids served as material for the preparation of liposomes.

Phytochemical and biological activities of Pinus halepensis mill., and their ethnomedicinal use

ETHNOPHARMACOLOGICAL RELEVANCE

Pinus halepensis Mill., is a Mediterranean medicinal plant with numerous traditional applications such as anti-scarring, antiseptic, astringent, antifungal, and anti-tuberculosis. It is used against diarrhea, wounds, rheumatism, cough, gastrointestinal illnesses, hypertension, and hemorrhoids.

AIM OF THE REVIEW

We critically summarized previous reports on the botanical, taxonomical, ecological, geographical distribution, phytochemical, and pharmacological results of P. halepensis Mill.

MATERIALS AND METHODS

To gather data on P. halepensis Mill., different scientific search engines were consulted such as Google Scholar, Scopus, Wiley Online, Scifinder, Web of Science, ScienceDirect, SpringerLink, PubMed. The collected data on P. halepensis Mill., were organised according to ethnomedicinal use, phytochemistry, and pharmacology.

RESULTS

Ethnomedicinal studies indicated that P. halepensis Mill., is used as a protective remedy against respiratory and digestive disorders, arterial hypertension, microbial infections. These medicinal uses vary based on the part used and regions. The extracts and essential oils of P. halepensis Mill., demonstrated several biological effects including antimicrobial, antidiabetic anti-inflammatory, cytotoxic, antiparasitic, and hepatoprotective. Traditional uses and biological effects of P. halepensis Mill., were attributed to the numerous molecules that belong to different chemical classes such as terpenoids, phenolic acids, flavonoids, fatty acids and steroids, aldehydes and ketones.

CONCLUSIONS

In vitro and in vivo investigations of P. halepensis Mill., extracts and essential oils showed interesting pharmacological activities supporting the traditional use of this species. Previous reports indicated that P. halepensis Mill., extracts and their constituents exhibited potent antibacterial, antifungal, antioxidant, protective, anticoagulant, anti-hemolytic, and anti-inflammatory effects. Further investigation is needed to reveal the full biological spectra of P. halepensis Mill., extracts and essential oils (using in vivo models) and to validate their industrial applications as a food additive. However, in-depth studies are required to investigate the biological properties and molecular mechanisms of P. halepensis Mill., secondary metabolites in the management of diabetes mellitus and the prevention of the neurodegenerative disorders development such as Alzheimer's and Parkinson's disease. Studies exploring pharmacological effects of P. halepensis Mill., bioactive components such as the antimicrobial, anti-inflammatory, and antiparasitic drugs are required to validate the clinical use of these molecules. The safety of P. halepensis Mill., and its bioactive compounds should be also investigated by carrying out further pharmacokinetic and toxicological experiments.

Multivalent, Stabilized Mannose-6-Phosphates for the Targeted Delivery of Toll-Like Receptor Ligands and Peptide Antigens

Mannose-6-phosphate (M6P) is recognized by the mannose-6-phosphate receptor and plays an important role in the transport of cargo to the endosomes, making it an attractive tool to improve endosomal trafficking of vaccines. We describe herein the assembly of peptide antigen conjugates carrying clusters of mannose-6-C-phosphonates (M6Po). The M6Po's are stable M6P mimics that are resistant to cleavage of the phosphate group by endogenous phosphatases. Two different strategies for the incorporation of the M6Po clusters in the conjugate have been developed: the first relies on a "post-assembly" click approach employing an M6Po bearing an alkyne functionality; the second hinges on an M6Po C-glycoside amino acid building block that can be used in solid-phase peptide synthesis. The generated conjugates were further equipped with a TLR7 ligand to stimulate dendritic cell (DC) maturation. While antigen presentation is hindered by the presence of the M6Po clusters, the incorporation of the M6Po clusters leads to increased activation of DCs, thus demonstrating their potential in improving vaccine adjuvanticity by intraendosomally active TLR ligands.

Rapid Entry into Biologically Relevant α,α-Difluoroalkylphosphonates Bearing Allyl Protection-Deblocking under Ru(II)/(IV)-Catalysis

A convenient synthetic route to α,α-difluoroalkylphosphonates is described. Structurally diverse aldehydes are condensed with LiF2CP(O)(OCH2CH═CH2)2. The resultant alcohols are captured as the pentafluorophenyl thionocarbonates and efficiently deoxygenated with HSnBu3, BEt3, and O2, and then smoothly deblocked with CpRu(IV)(π-allyl)quinoline-2-carboxylate (1-2 mol %) in methanol as an allyl cation scavenger. These mild deprotection conditions provide access to free α,α-difluoroalkylphosphonates in nearly quantitative yield. This methodology is used to rapidly construct new bis-α,α-difluoroalkyl phosphonate inhibitors of PTPIB (protein phosphotyrosine phosphatase-1B).

Regioselective Single-Electron Tsuji-Trost Reaction of Allylic Alcohols: A Photoredox/Nickel Dual Catalytic Approach

A radical-mediated functionalization of allyl alcohol derived partners with a variety of alkyl 1,4-dihydropyridines via photoredox/nickel dual catalysis is described. This transformation transpires with high linear and E-selectivity, avoiding the requirement of harsh conditions (e.g., strong base, elevated temperature). Additionally, using aryl sulfinate salts as radical precursors, allyl sulfones can also be obtained. Kinetic isotope effect experiments implicated oxidative addition of the nickel catalyst to the allylic electrophile as the turnover-limiting step, supporting previous computational studies.

General Linker Diversification Approach to Bivalent Ligand Assembly: Generation of an Array of Ligands for the Cation-Independent Mannose 6-Phosphate Receptor

A generalized strategy is presented for the rapid assembly of a set of bivalent ligands with a variety of linking functionalities from a common monomer. Herein, an array of phosphatase-inert mannose-6-phosphonate-presenting ligands for the cation-independent-mannose 6-phosphate receptor (CI-MPR) is constructed. Receptor binding affinity varies with linking functionality-the simple amide and 1,5-triazole(tetrazole) being preferred over the 1,4-triazole. This approach is expected to find application across chemical biology, particularly in glycoscience, wherein multivalency often governs molecular recognition.

Gold nanoparticles decorated with mannose-6-phosphate analogues

Herein, the preparation of neoglycoconjugates bearing mannose-6-phosphate analogues is described by: (a) synthesis of a cyclic sulfate precursor to access the carbohydrate head-group by nucleophilic displacement with an appropriate nucleophile; (b) introduction of spacers on the mannose-6-phosphate analogues via Huisgen's cycloaddition, the Julia reaction, or the thiol-ene reaction under ultrasound activation. With the resulting compounds in hand, gold nanoparticles could be functionalized with various carbohydrate derivatives (glycoconjugates) and then tested for angiogenic activity. It was observed that the length and flexibility of the spacer separating the sugar analogue from the nanoparticle have little influence on the biological response. One particular nanoparticle system substantially inhibits blood vessel growth in contrast to activation by the corresponding monomeric glycoconjugate, thereby demonstrating the importance of multivalency in angiogenic activity.