Gold nanoparticles from magnetite for the detection of amyloid proteins in neurodegenerative diseases

Introduction. Currently, neurodegenerative diseases (ND) are the fourth leading cause of death worldwide that pose a great challenge in the development of tools for early diagnosis. Thus, advances in science seek sensitive and selective detection systems and this manuscript will highlight the importance of nanotechnology. Material and methods. A literature review was conducted on the representative findings of NPs technologies in neurodegenerative diseases. Articles written in both English and Spanish were included. References between 2015-2021 were also taken into account. Results. One of the most representative techniques, AuNP was specifically implemented, together with a magnetic center composed of magnetite, which has as a specific ligand with a C-terminal cysteine domain present in the B-amyloid protein, which adhere directly to the surface of the NPs, characterizing the anomalous protein. Subsequently, by means of nanosensors capable of detecting and measuring different concentrations, these pathologies are identified at an early stage. Conclusions. Today, along with the advent of biotechnology, it has been possible to design techniques with NPs that allow the identification of specific mutations and provide diagnosis in individuals. In the investigative models of AuNP, it is possible to infer that the capabilities that make them representative focus on their magnetism and biofunctionality, by specifically binding to amyloid peptides and other ligands present in the protein, which are the major components of amyloid plaques used in these studies.

Mechanism-Based Strategy for Optimizing HaloTag Protein Labeling

HaloTag labeling technology has introduced unrivaled potential in protein chemistry, molecular and cellular biology. A wide variety of ligands have been developed to meet the specific needs of diverse applications, but only a single protein tag, DhaAHT, is routinely used for their incorporation. Following a systematic kinetic and computational analysis of different reporters, tetramethylrhodamine and three 4-stilbazolium-based fluorescent ligands, we showed that the mechanism of incorporating different ligands depends both on the binding step and the efficiency of the chemical reaction. By studying the different haloalkane dehalogenases DhaA, LinB, and DmmA, we found that the architecture of the access tunnels is critical for the kinetics of both steps and the ligand specificity. We show that highly efficient labelling with specific ligands is achievable with natural dehalogenases. We propose a simple protocol for selecting the optimal protein tag for a specific ligand from a wide pool of available enzymes with diverse access tunnel architectures. The application of this protocol eliminates a need for expensive and laborious protein engineering.

Behavioral and Slice Electrophysiological Assessment of DREADD Ligand, Deschloroclozapine (DCZ) in Rats

Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) have become a premier neuroscience research tool for enabling reversible manipulations of cellular activity following experimenter-controlled delivery of a DREADD-specific ligand. However, several DREADD ligands, e.g., clozapine-N-oxide (CNO), have metabolic and off-target effects that may confound experimental findings. New DREADD ligands aim to reduce metabolic and potential off-target effects while maintaining strong efficacy for the designer receptors. Recently a novel DREADD ligand, deschloroclozapine (DCZ), was shown to induce chemogenetic-mediated cellular and behavioral effects in mice and monkeys without detectable side effects. The goal of the present study was to examine the effectiveness of systemic DCZ for DREADD-based chemogenetic manipulations in behavioral and slice electrophysiological applications in rats. We demonstrate that a relatively low dose of DCZ (0.1 mg/kg) supports excitatory DREADD-mediated cFos induction, DREADD-mediated inhibition of a central amygdala-dependent behavior, and DREADD-mediated inhibition of neuronal activity in a slice electrophysiology preparation. In addition, we show that this dose of DCZ does not alter gross locomotor activity or induce a place preference/aversion in control rats without DREADD expression. Together, our findings support the use of systemic DCZ for DREADD-based manipulaations in rats, and provide evidence that DCZ is a superior alternative to CNO.

Secondary-structure switch regulates the substrate binding of a YopJ family acetyltransferase

The Yersinia outer protein J (YopJ) family effectors are widely deployed through the type III secretion system by both plant and animal pathogens. As non-canonical acetyltransferases, the enzymatic activities of YopJ family effectors are allosterically activated by the eukaryote-specific ligand inositol hexaphosphate (InsP6). However, the underpinning molecular mechanism remains undefined. Here we present the crystal structure of apo-PopP2, a YopJ family member secreted by the plant pathogen Ralstonia solanacearum. Structural comparison of apo-PopP2 with the InsP6-bound PopP2 reveals a substantial conformational readjustment centered in the substrate-binding site. Combining biochemical and computational analyses, we further identify a mechanism by which the association of InsP6 with PopP2 induces an α-helix-to-β-strand transition in the catalytic core, resulting in stabilization of the substrate recognition helix in the target protein binding site. Together, our study uncovers the molecular basis governing InsP6-mediated allosteric regulation of YopJ family acetyltransferases and further expands the paradigm of fold-switching proteins.

CXCR1/2 Inhibitor Ladarixin Ameliorates the Insulin Resistance of 3T3-L1 Adipocytes by Inhibiting Inflammation and Improving Insulin Signaling

Type 2 diabetes mellitus is a severe public health issue worldwide. It displays a harmful effect on different organs as the eyes, kidneys and neural cells due to insulin resistance and high blood glucose concentrations. To date, the available treatments for this disorder remain limited. Several reports have correlated obesity with type 2 diabetes. Mainly, dysfunctional adipocytes and the regulation of high secretion of inflammatory cytokines are the crucial links between obesity and insulin resistance. Several clinical and epidemiological studies have also correlated the onset of type 2 diabetes with inflammation, which is now indicated as a new target for type 2 diabetes treatment. Thus, it appears essential to discover new drugs able to inhibit the secretion of proinflammatory adipocytokines in type 2 diabetes. Adipocytes produce inflammatory cytokines in response to inflammation or high glucose levels. Once activated by a specific ligand, CXCR1 and CXCR2 mediate some cytokines’ effects by activating an intracellular signal cascade once activated by a specific ligand. Therefore, it is conceivable to hypothesize that a specific antagonist of these receptors may ameliorate type 2 diabetes and glucose metabolism. Herein, differentiated 3T3-L1-adipocytes were subjected to high glucose or inflammatory conditions or the combination of both and then treated with ladarixin, a CXCR1/2 inhibitor. The results obtained point towards the positive regulation by ladarixin on insulin sensitivity, glucose transporters GLUT1 and GLUT4, cytokine proteome profile and lipid metabolism, thus suggesting ladarixin as a potentially helpful treatment in type 2 diabetes mellitus and obesity.

PSMA Theranostics: Science and Practice

Prostate cancer (PCa) causes significant morbidity and mortality in men globally. While localized PCa may be managed with curative intent by surgery and/or radiation therapy, the management of advanced hormone resistant metastatic disease (mCRPC) is more challenging. Theranostics is a principle based on the ability to use an organ specific ligand and label it to both a diagnostic and a therapeutic agent. The overexpression of prostate specific membrane antigen (PSMA) on prostate cancer cells creates a unique opportunity for development of targeted radionuclide therapy. The use of both beta and alpha emitting particles has shown great success. Several clinical trials have been initiated assessing the efficacy and safety profile of these radionuclide agents. The results are encouraging with PSMA directed radioligand therapy performing well in patients who have exhausted all other standard treatment options. Future studies need to assess the timing of introduction of these radionuclide therapies in the management schema of mCRPC. Drugs or therapies are not without side effects and targeted radionuclide therapies presents a new set of toxicities including xerostomia and myelosuppression. New therapeutic strategies are being explored to improve outcomes while keeping toxicities to a minimum. This review aims to look at the various PSMA labelled tracers that form part of the theragnostic approach and subsequently delve into the progress made in the area of radionuclide therapy.

Functional Characterization of Olfactory Receptors in the Thyroid Gland

Olfactory receptors (ORs) are almost ubiquitously expressed in the human body. However, information about their functions in these tissues is lacking. To date, no functional characterization of expressed ORs in the human thyroid has been performed. In this study, we detected and compared the expression of OR2H2 and OR2W3 in healthy and malignant cell lines and their corresponding tissues, respectively. We demonstrated that stimulation of ORs by their specific ligand resulted in a transient increase in intracellular calcium and cAMP concentrations. In the case of OR2H2, the downstream signaling cascade analysis revealed that adenylate cyclase (AC) and phosphoinositide phospholipase C (PLC) were involved. Furthermore, OR2H2 and OR2W3 activation affected migration, proliferation, and invasion. These are the first insights that ORs influence physiology-relevant processes in the healthy and malignant thyroid.

Recent Advances in the Therapeutic Development of Receptor Tyrosine Kinases (RTK) against Different Types of Cancer

Receptor Tyrosine Kinases (RTKs) are an important class of receptors involved in regulating different cellular functions. The usual pathway of RTK activation involves specific ligand binding, dimerization and trans-autophosphorylation. Recently, RTK has been extensively studied as they have potential applications in targeted cancer therapy. RTK-based therapeutic strategies are promising because dysfunction of RTK is connected to a variety of diseases. More specifically, RTK has been widely associated with different types of cancer and related diseases. The chapter aims to cover recent advances and challenges in RTK related research, to get an overview of the problems and possibilities associated with targeted therapy. This will help in deciphering novel therapeutic applications in the future.

Optimised GMP-compliant production of [18F]DPA-714 on the Trasis AllinOne module

Background The translocator protein 18 kDa is recognised as an important biomarker for neuroinflammation due to its soaring expression in microglia. This process is common for various neurological disorders. DPA-714 is a potent TSPO-specific ligand which found its use in Positron Emission Tomography following substitution of fluorine-19 with fluorine-18, a positron-emitting radionuclide. [18F]DPA-714 enables visualisation of inflammatory processes in vivo non-invasively. Radiolabelling of this tracer is well described in literature, including validation for clinical use. Here, we report significant enhancements to the process which resulted in the design of a fully GMP-compliant robust synthesis of [18F]DPA-714 on a popular cassette-based system, Trasis AllinOne, boosting reliability, throughput, and introducing a significant degree of simplicity. Results [18F]DPA-714 was synthesised using the classic nucleophilic aliphatic substitution on a good leaving group, tosylate, with [18F]fluoride using tetraethylammonium bicarbonate in acetonitrile at 100∘C. The process was fully automated on a Trasis AllinOne synthesiser using an in-house designed cassette and sequence. With a relatively small precursor load of 4 mg, [18F]DPA-714 was obtained with consistently high radiochemical yields of 55-71% (n=6) and molar activities of 117-350 GBq/µmol at end of synthesis. With a single production batch, starting with 31-42 GBq of [18F]fluoride, between 13-20 GBq of the tracer can be produced, enabling multi-centre studies. Conclusion To the best of our knowledge, the process presented herein is the most efficient [18F]DPA-714 synthesis, with advantageous GMP compliance. The use of a Trasis AllinOne synthesiser increases reliability and allows rapid training of production staff.

Phase Ia study of CBP-1008, a bi-specific ligand drug conjugate targeting FRα and TRPV6, in patients with advanced solid tumors.

3077 Background: CBP-1008 is a first-in-class bi-specific ligand drug conjugate targeting folate receptor α (FRα) and vanilloid subfamily member 6 of transient receptor potential channels (TRPV6) with a high potency tublin inhibitor payload, monomethyl auristatin E (MMAE). A first-in-human, multicenter, phase I study of CBP-1008 (NCT 04740398) is ongoing, and we herein report the preliminary result of part A which is to evaluate the safety, tolerability, pharmacokinetics, and antitumor activity of CBP-1008 in solid tumors. Methods: Dose escalation commenced in single-patient cohorts for the first 2 planned dose levels and then followed by a standard 3 + 3 scheme. CBP-1008 was administered as intravenous infusion at escalating doses (0.015, 0.03, 0.12, 0.15, and 0.18 mg/kg). The primary endpoints were to determine the safety and maximum tolerated dose (MTD). Adverse events (AEs) and dose-limiting toxicities (DLTs) were evaluated. Results: Eighteen patients with advanced solid tumors who had failed multiple systemic treatment regimens were enrolled. The diseases include colorectal cancer (n = 7), breast cancer (n = 5), non-small cell lung cancer (n = 2), ovarian cancer (n = 2), adrenocortical carcinoma (n = 1), and follicular dendritic cell sarcoma (n = 1). The DLTs observed included grade 4 hypophosphatemia (0.15 mg/kg), grade 4 neutropenia (0.12, 0.15, and 0.18 mg/kg), grade 4 febrile neutropenia (FN) (0.18 mg/kg), grade 3 hyperglycemia (0.15 mg/kg), and grade 3 alanine aminotransferase (ALT) elevation (0.18 mg/kg). The most common all grade AEs suspected to be drug-related were fever (83.3%, totally limited to grade 1-2), aspartate aminotransferase (AST) elevation (72.2%, 5.6% evaluated as grade 3-4), leukopenia (66.7%, 27.8% as grade 3-4), neutropenia (66.7%, 38.9% as grade 3-4) and hypohemoglobinemia (55.6%, 5.6% as grade 3-4), with no drug-related deaths. MTD is estimated between 0.15 mg/kg and 0.18 mg/kg Q2W. Best overall response was partial response (PR) in 1 patient at 0.18 mg/kg and 4 patients (22.2%) achieved stable disease (SD). Responses occurred in patients with FRα and/or TRPV6 -positive expression advanced solid tumors. Conclusions: CBP-1008 has demonstrated acceptable safety profile. Tumor response correlating with dosing and FRα/TRPV6 receptor expression levels has been well observed. Clinical trial information: 04740398.