There is an immediate need to drastically reduce the emissions associated with global fossil fuel consumption in order to limit climate change. However, carbon-based materials, chemicals, and ...transportation fuels are predominantly made from fossil sources and currently there is no alternative source available to adequately displace them. Gas-fermenting microorganisms that fix carbon dioxide (CO2) and carbon monoxide (CO) can break this dependence as they are capable of converting gaseous carbon to fuels and chemicals. As such, the technology can utilize a wide range of feedstocks including gasified organic matter of any sort (e.g., municipal solid waste, industrial waste, biomass, and agricultural waste residues) or industrial off-gases (e.g., from steel mills or processing plants). Gas fermentation has matured to the point that large-scale production of ethanol from gas has been demonstrated by two companies. This review gives an overview of the gas fermentation process, focusing specifically on anaerobic acetogens. Applications of synthetic biology and coupling gas fermentation to additional processes are discussed in detail. Both of these strategies, demonstrated at bench-scale, have abundant potential to rapidly expand the commercial product spectrum of gas fermentation and further improve efficiencies and yields.
We investigated whether a training protocol that involved 3 min of intense intermittent exercise per week--within a total training time commitment of 30 min including warm up and cool down--could ...increase skeletal muscle oxidative capacity and markers of health status. Overweight/obese but otherwise healthy men and women (n = 7 each; age = 29±9 y; BMI = 29.8±2.7 kg/m2) performed 18 training sessions over 6 wk on a cycle ergometer. Each session began with a 2 min warm-up at 50 W, followed by 3×20 s "all-out" sprints against 5.0% body mass (mean power output: ∼450-500 W) interspersed with 2 min of recovery at 50 W, followed by a 3 min cool-down at 50 W. Peak oxygen uptake increased by 12% after training (32.6±4.5 vs. 29.1±4.2 ml/kg/min) and resting mean arterial pressure decreased by 7% (78±10 vs. 83±10 mmHg), with no difference between groups (both p<0.01, main effects for time). Skeletal muscle biopsy samples obtained before and 72 h after training revealed increased maximal activity of citrate synthase and protein content of cytochrome oxidase 4 (p<0.01, main effect), while the maximal activity of β-hydroxy acyl CoA dehydrogenase increased in men only (p<0.05). Continuous glucose monitoring measured under standard dietary conditions before and 48-72 h following training revealed lower 24 h average blood glucose concentration in men following training (5.4±0.6 vs. 5.9±0.5 mmol/L, p<0.05), but not women (5.5±0.4 vs. 5.5±0.6 mmol/L). This was associated with a greater increase in GLUT4 protein content in men compared to women (138% vs. 23%, p<0.05). Short-term interval training using a 10 min protocol that involved only 1 min of hard exercise, 3x/wk, stimulated physiological changes linked to improved health in overweight adults. Despite the small sample size, potential sex-specific adaptations were apparent that warrant further investigation.
Pain medication plays an important role in the treatment of acute and chronic pain conditions, but some drugs, opioids in particular, have been overprescribed or prescribed without adequate ...safeguards, leading to an alarming rise in medication-related overdose deaths. The NIH Helping to End Addiction Long-term (HEAL) Initiative is a trans-agency effort to provide scientific solutions to stem the opioid crisis. One component of the initiative is to support biomarker discovery and rigorous validation in collaboration with industry leaders to accelerate high-quality clinical research into neurotherapeutics and pain. The use of objective biomarkers and clinical trial end points throughout the drug discovery and development process is crucial to help define pathophysiological subsets of pain, evaluate target engagement of new drugs and predict the analgesic efficacy of new drugs. In 2018, the NIH-led Discovery and Validation of Biomarkers to Develop Non-Addictive Therapeutics for Pain workshop convened scientific leaders from academia, industry, government and patient advocacy groups to discuss progress, challenges, gaps and ideas to facilitate the development of biomarkers and end points for pain. The outcomes of this workshop are outlined in this Consensus Statement.
In recent years, there has been a growing interest in therapeutic peptides within the pharmaceutical industry with more than 50 peptide drugs on the market, approximately 170 in clinical trials, and ...>200 in preclinical development. However, the current state of the art in peptide synthesis involves primarily legacy technologies with use of large amounts of highly hazardous reagents and solvents and little focus on green chemistry and engineering. In 2016, the ACS Green Chemistry Institute Pharmaceutical Roundtable identified development of greener processes for peptide API as a critical unmet need, and as a result, a new Roundtable team formed to address this important area. The initial focus of this new team is to highlight best practices in peptide synthesis and encourage much needed innovations. In this Perspective, we aim to summarize the current challenges of peptide synthesis and purification in terms of sustainability, highlight possible solutions, and encourage synergies between academia, the pharmaceutical industry, and contract research organizations/contract manufacturing organizations.
Abstract
The tetrahydroisoquinoline (THIQ) moiety is a privileged substructure of many bioactive natural products and semi-synthetic analogs. Plants manufacture more than 3,000 THIQ alkaloids, ...including the opioids morphine and codeine. While microbial species have been engineered to synthesize a few compounds from the benzylisoquinoline alkaloid (BIA) family of THIQs, low product titers impede industrial viability and limit access to the full chemical space. Here we report a yeast THIQ platform by increasing production of the central BIA intermediate (
S
)-reticuline to 4.6 g L
−1
, a 57,000-fold improvement over our first-generation strain. We show that gains in BIA output coincide with the formation of several substituted THIQs derived from amino acid catabolism. We use these insights to repurpose the Ehrlich pathway and synthesize an array of THIQ structures. This work provides a blueprint for building diverse alkaloid scaffolds and enables the targeted overproduction of thousands of THIQ products, including natural and semi-synthetic opioids.
CRISPR/Cas9-based functional genomics have transformed our ability to elucidate mammalian cell biology. However, most previous CRISPR-based screens were conducted in cancer cell lines rather than ...healthy, differentiated cells. Here, we describe a CRISPR interference (CRISPRi)-based platform for genetic screens in human neurons derived from induced pluripotent stem cells (iPSCs). We demonstrate robust and durable knockdown of endogenous genes in such neurons and present results from three complementary genetic screens. First, a survival-based screen revealed neuron-specific essential genes and genes that improved neuronal survival upon knockdown. Second, a screen with a single-cell transcriptomic readout uncovered several examples of genes whose knockdown had strikingly cell-type-specific consequences. Third, a longitudinal imaging screen detected distinct consequences of gene knockdown on neuronal morphology. Our results highlight the power of unbiased genetic screens in iPSC-derived differentiated cell types and provide a platform for systematic interrogation of normal and disease states of neurons.
Display omitted
Display omitted
•A CRISPR interference platform for genetic screens in human iPSC-derived neurons•Survival screens uncover genes essential for neurons, but not iPSCs or cancer cells•Single-cell RNA-seq screens reveal distinct neuronal roles for ubiquitous genes•Arrayed high-content screens uncover genes controlling neuronal morphology
Tian, Gachechiladze, and Ludwig et al. present a CRISPR interference-based platform for genetic screens in human iPSC-derived neurons. This platform enables systematic elucidation of gene function in human neurons and reveals neuron-specific roles of genes for survival, transcriptomics states, and morphology.
Nogo-A is a membrane protein of the central nervous system (CNS) restricting neurite growth and synaptic plasticity via two extracellular domains: Nogo-66 and Nogo-A-Δ20. Receptors transducing ...Nogo-A-Δ20 signaling remained elusive so far. Here we identify the G protein-coupled receptor (GPCR) sphingosine 1-phosphate receptor 2 (S1PR2) as a Nogo-A-Δ20-specific receptor. Nogo-A-Δ20 binds S1PR2 on sites distinct from the pocket of the sphingolipid sphingosine 1-phosphate (S1P) and signals via the G protein G13, the Rho GEF LARG, and RhoA. Deleting or blocking S1PR2 counteracts Nogo-A-Δ20- and myelin-mediated inhibition of neurite outgrowth and cell spreading. Blockade of S1PR2 strongly enhances long-term potentiation (LTP) in the hippocampus of wild-type but not Nogo-A(-/-) mice, indicating a repressor function of the Nogo-A/S1PR2 axis in synaptic plasticity. A similar increase in LTP was also observed in the motor cortex after S1PR2 blockade. We propose a novel signaling model in which a GPCR functions as a receptor for two structurally unrelated ligands, a membrane protein and a sphingolipid. Elucidating Nogo-A/S1PR2 signaling platforms will provide new insights into regulation of synaptic plasticity.
As indicated by the profound cognitive impairments caused by cholinergic receptor antagonists, cholinergic neurotransmission has a vital role in cognitive function, specifically attention and memory ...encoding. Abnormally regulated cholinergic neurotransmission has been hypothesized to contribute to the cognitive symptoms of neuropsychiatric disorders. Loss of cholinergic neurons enhances the severity of the symptoms of dementia. Cholinergic receptor agonists and acetylcholinesterase inhibitors have been investigated for the treatment of cognitive dysfunction. Evidence from experiments using new techniques for measuring rapid changes in cholinergic neurotransmission provides a novel perspective on the cholinergic regulation of cognitive processes. This evidence indicates that changes in cholinergic modulation on a timescale of seconds is triggered by sensory input cues and serves to facilitate cue detection and attentional performance. Furthermore, the evidence indicates cholinergic induction of evoked intrinsic, persistent spiking mechanisms for active maintenance of sensory input, and planned responses. Models have been developed to describe the neuronal mechanisms underlying the transient modulation of cortical target circuits by cholinergic activity. These models postulate specific locations and roles of nicotinic and muscarinic acetylcholine receptors and that cholinergic neurotransmission is controlled in part by (cortical) target circuits. The available evidence and these models point to new principles governing the development of the next generation of cholinergic treatments for cognitive disorders.
The diagnosis of multiple myeloma can be challenging, even for experienced physicians, and requires close collaboration between numerous disciplines (orthopedics, radiology, nuclear medicine, ...radiation therapy, hematology and oncology) before the final diagnosis of myeloma is made. The definition of multiple myeloma is based on the presence of clinical, biochemical, histopathological, and radiological markers of disease. Specific tests are needed both at presentation and during follow-up in order to reach the correct diagnosis and characterize the disease precisely. These tests can also serve prognostic purposes and are useful for follow-up of myeloma patients. Molecular analyses remain pivotal for defining high-risk myeloma and are used in updated patient stratifications, while minimal residual disease assessment via flow cytometry, molecular techniques and radiological approaches provides additional prognostic information on patients' long-term outcome. This pivotal information will guide our future treatment decisions in forthcoming clinical trials. The European Myeloma Network group updated their guidelines on different diagnostic recommendations, which should be of value to enable appropriate use of the recommendations both at diagnosis and during follow-up.
PDF
