A competitive ligand-binding assay to detect neutralizing antibodies to a bispecific drug using a used multiplex Meso Scale Discovery platform

Background: Monitoring appearance of neutralizing antibodies (NAbs) to multidomain large molecule drugs is a challenging task. Materials & methods: Here, we report development of a competitive ligand-binding assay for detection of NAbs to a bispecific candidate drug using a used multiplex Meso Scale Discovery platform, which allows for detection of NAbs to both drug arms in the same sample. Results: The assay has sensitivity better than 250 ng/ml and is tolerant to the presence of drug at concentration >600 μg/ml and to the level of soluble target(s) >400 ng/ml. Conclusion: Our data suggest that multiplex approach can be successfully used for development of NAb assays in competitive ligand-binding assay format.

P2X7 Receptors and TMEM16 Channels Are Functionally Coupled with Implications for Macropore Formation and Current Facilitation

P2X7 receptors (P2X7) are cationic channels involved in many diseases. Following their activation by extracellular ATP, distinct signaling pathways are triggered, which lead to various physiological responses such as the secretion of pro-inflammatory cytokines or the modulation of cell death. P2X7 also exhibit unique behaviors, such as “macropore” formation, which corresponds to enhanced large molecule cell membrane permeability and current facilitation, which is caused by prolonged activation. These two phenomena have often been confounded but, thus far, no clear mechanisms have been resolved. Here, by combining different approaches including whole-cell and single-channel recordings, pharmacological and biochemical assays, CRISPR/Cas9 technology and cell imaging, we provide evidence that current facilitation and macropore formation involve functional complexes comprised of P2X7 and TMEM16, a family of Ca2+-activated ion channel/scramblases. We found that current facilitation results in an increase of functional complex-embedded P2X7 open probability, a result that is recapitulated by plasma membrane cholesterol depletion. We further show that macropore formation entails two distinct large molecule permeation components, one of which requires functional complexes featuring TMEM16F subtype, the other likely being direct permeation through the P2X7 pore itself. Such functional complexes can be considered to represent a regulatory hub that may orchestrate distinct P2X7 functionalities.

MO799IS COMBINATION OF MAINTENANCE HEMODIALYSIS WITH HEMOPERFUSION AN EFFECTIVE METHOD IN MANAGEMENT OF RENAL OSTEODYSTROPHY AND INFLAMMATION IN HEMODIALYSIS PATIENTS?

Background and Aims Some of the conditions which occur in maintenance hemodialysis (MHD) patients with a high incidence resulting in a decline in their quality of life, include malnutrition, renal osteodystrophy, refractory hypertension and chronic systemic inflammation. In developing countries, due to the low level of economic development, low-flux dialysis is the main means of extracorporeal blood purification therapy. But it can hardly remove the middle and large molecule uremic toxins and protein-bound toxins; as a result, the patients suffer from long-term complications and poor quality of life. In this study, we attempted to investigate whether the combination of maintenance hemodialysis (MHD) with hemoperfusion (HP) could improve the clearance rate of middle and large molecule uremic toxins so as to improve their uremic complications. Method A total of 54 patients, who underwent routine hemodialysis, were assessed in this study. Those patients were randomly divided into two groups: Group 1 (27 patients) received combined treatment of HD with hemoperfusion (HP) in this regimen: HD 2 times a week with HD+HP once a week two times in a row, then after two weeks, and afterwards once a month as a maintenance treatment. Group 2 (27 patients) was only undergoing maintenance HD 3 times a week. The clinical and laboratory properties of both groups were followed up for 18 months, whereas the primary outcomes included normal clinical data, high sensitive C-reactive protein (hsCRP), immunoreactive parathyroid hormone (iPTH), phosphorus (P04), calcium (Ca), albumin, iron (Fe), total iron binding capacity (TIBC), hemoglobin, Epo doses and types of hypertensive drugs. Results At the end of the 18-month observation, the serum concentration of albumin, P04, hsCRP, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were lower with Group 1 than with Group 2 (p<0.05). Whereas, higher levels of iPTH were noticed in group 1, but when the laboratory and clinical data are analysed of the group 1 alone a statistically significant lower values after the observational period are noticed especially in the serum values of iPTH (p<0.05), P04 (p<0.001), CRP (p<0.011), SBP and DBP (p<0.05). Conclusion HD+HP was superior to HD in regularly eliminating middle and large molecule uremic toxins accumulated in the body which is mostly shown through reducing the values of iPTH and hsCRP. These findings suggest a potential role for HD+HP in the treatment of inflammation and renal osteodystrophy as well, because lowering these values of iPTH leads to a normalization of other minerals which is expected and therefore leads to a stabilization of this long-term uremic complications, which can improve the overall general condition of the MHD patient.

P2X7 Receptors and TMEM16 Channels Form a Hub with Implications for Macropore Formation and Current Facilitation

P2X7 receptors (P2X7) are cationic channels involved in many diseases. They exhibit unique behaviors, such as “macropore” formation, which corresponds to enhanced large molecule cell membrane permeability, and current facilitation, which is caused by prolonged activation. These two phenomena have often been confounded, but thus far no clear mechanisms have been resolved. Here we provide evidence that current facilitation and macropore formation involve functional complexes comprised of P2X7 and TMEM16, a family of Ca2+-activated ion channel/scramblases. We found that current facilitation results in an increase of complex-embedded P2X7 open channel probability, a result mimicked by plasma membrane cholesterol depletion. We further show that macropore formation entails two distinct large molecule permeation components, one of which requires protein complexes featuring TMEM16F subtype, the other likely being direct permeation through the P2X7 pore itself. Such protein complexes can be considered to represent a regulatory hub intimately involved in distinct P2X7 functionalities.

Molecule Set Comparator (MSC): a CDK-based open rich‐client tool for molecule set similarity evaluations

The open rich-client Molecule Set Comparator (MSC) application enables a versatile and fast comparison of large molecule sets with a unique inter-set molecule-to-molecule mapping obtained e.g. by molecular-recognition-oriented machine learning approaches. The molecule-to-molecule comparison is based on chemical descriptors obtained with the Chemistry Development Kit (CDK), such as Tanimoto similarities, atom/bond/ring counts or physicochemical properties like logP. The results are summarized and presented graphically by interactive histogram charts that can be examined in detail and exported in publication quality.