Biology subjects

Paulvannan, K.

Publications and source records attributed to Paulvannan, K..

4 recordsLinked to original sources

bioRxiv2024

A low-cost, open-source 3D printer for multimaterial and high-throughput direct ink writing of soft and living materials

Direct ink writing is a 3D printing method that is compatible with a wide range of structural, elastomeric, electronic, and living materials, and it continues to expand its uses into physics, engineering, and biology laboratories. However, the large footprint, closed hardware and software ecosystems, and expense of commercial systems often hamper widespread adoption. Here, we present a compact, simple-to-build, low-cost, multimaterial, and high-throughput direct ink writing 3D printer platform with detailed assembly files and instructions provided freely online. In contrast to existing low-cost 3D printers and bioprinters, which typically modify off-the-shelf plastic 3D printers, this system is built from scratch, offering a lower cost and full customizability. Despite its low cost, we demonstrate advanced active mixing and multimaterial multinozzle 3D (MM3D) printing methods, which previously have relied on expensive and custom motion control platforms. We finally introduce embedded multinozzle and 3D gradient nozzle designs that offer high throughput and graded 3D parts. This powerful, easy-to-build, and customizable printing platform can help stimulate a vibrant biomaker community of engineers, biologists, and educators.

bioengineering↗

bioRxiv2024

An ALS Therapeutic Assembly Modulator Target in Peripheral Blood Mononuclear Cells: Implications for ALS Pathophysiology, Therapeutics, and Diagnostics

Assembly modulators are a new class of allosteric site-targeted therapeutic small molecules, some of which are effective at restoring nuclear localization of TDP-43 in ALS cellular models, and which display efficacy in a variety of ALS animal models. These compounds have been shown to bind selectively to a small subset of protein disulfide isomerase (PDI), a protein implicated in ALS pathophysiology. The targeted subset of PDI is found within a novel, transient and energy-dependent multi-protein complex that includes other important members of the ALS interactome, such as TDP-43, RanGTPase, and selective autophagy receptor p62/SQSTM1. We demonstrate here that a similar multi-protein complex drug target is present in PBMCs as isolated by energy-dependent drug resin affinity chromatography (eDRAC) and characterized by mass spectrometry and by Western blot (WB). Signature alterations in the composition of the multi-protein complex in PBMCs from ALS patients compared to PBMCs from healthy individuals were identified by WB of eDRAC bound proteins, thereby extending earlier literature suggesting PBMC dysfunction in ALS. Changes in the PBMC drug target in ALS patients compared to healthy individuals include diminished p62/SQSTM1 and appearance of a 17kDa post-translationally modified form of RanGTPase. These changes are not readily apparent from analysis of whole cell extracts, as the individual protein components within the drug target multi-protein complex comprise only small percentages of the total of those component proteins in the extract. Furthermore, whole blood from ALS patients shows a distinctive degradation of total RanGTPase not observed in blood from healthy individuals. This degradation appears to be rescued by treatment of whole blood from ALS patients for 72 hrs with ALS-active assembly modulator small molecules. Our findings are consistent with the hypothesis that ALS is fundamentally a disorder of homeostasis that can be detected early, prior to disability, in blood by the methods described, and restored to the healthy state by assembly modulator drug treatment.

physiology↗

bioRxiv2023

Protein Assembly Modulation: A New Approach to ALS Therapeutics

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease with a complex, multifactorial pathophysiology, most commonly manifest as loss of motor neurons. We introduce a new mechanism of ALS pathogenesis via a novel drug-like small molecule series that targets protein disulfide isomerase (PDI) within a previously unappreciated transient and energy-dependent multi-protein complex. This novel drug was found to have activity in cellular models for both familial and sporadic ALS, as well as in transgenic worms, flies, and mice bearing a diversity of human genes with ALS-associated mutations. These compounds were initially identified as modulators of human immunodeficiency virus (HIV) capsid assembly in cell-free protein synthesis and assembly (CFPSA) systems, with demonstrated antiviral activity in cell culture. Their advancement as ALS-therapeutics, and the subsequent separation of activity against HIV and ALS in chemical subseries through structure-activity-relationship optimization, may provide insights into the molecular mechanisms governing pathophysiology of disordered homeostasis relevant to ALS.

neuroscience↗

bioRxiv2021

From COVID-19 to the Common Cold: Novel Host-Targeted, Pan-Respiratory Antiviral Small Molecule Therapeutics

We present a novel small molecule antiviral chemotype that was identified by an unconventional cell-free protein synthesis and assembly-based phenotypic screen for modulation of viral capsid assembly. Activity of PAV-431, a representative compound from the series, has been validated against infectious virus in multiple cell culture models for all six families of viruses causing most respiratory disease in humans. In animals this chemotype has been demonstrated efficacious for Porcine Epidemic Diarrhea Virus (a coronavirus) and Respiratory Syncytial Virus (a paramyxovirus). PAV-431 is shown to bind to the protein 14-3-3, a known allosteric modulator. However, it only appears to target the small subset of 14-3-3 which is present in a dynamic multi-protein complex whose components include proteins implicated in viral lifecycles and in innate immunity. The composition of this target multi-protein complex appears to be modified upon viral infection and largely restored by PAV-431 treatment. Our findings suggest a new paradigm for understanding, and drugging, the host-virus interface, which leads to a new clinical therapeutic strategy for treatment of respiratory viral disease.

biochemistry↗