A stable chemokine gradient controls directional persistence of migrating dendritic cells

Navigation of dendritic cells (DCs) from the site of infection to lymphoid organs is guided by concentration gradients of CCR7 ligands. How cells interpret chemokine gradients and how they couple directional sensing to polarization and persistent chemotaxis has remained largely elusive. Previous experimental systems were limited in the ability to control fast de novo formation of the final gradient slope, long-lasting stability of the gradient and to expose cells to dynamic stimulation. Here, we used a combination of microfluidics and quantitative in vitro live cell imaging to elucidate the chemotactic sensing strategy of DCs. The microfluidic approach allows us to generate soluble gradients with high spatio-temporal precision and to analyze actin dynamics, cell polarization, and persistent directional migration in both static and dynamic environments. We demonstrate that directional persistence of DC migration requires steady-state characteristics of the soluble gradient instead of temporally rising CCL19 concentration, implying that spatial sensing mechanisms control chemotaxis of DCs. Kymograph analysis of actin dynamics revealed that the presence of the CCL19 gradient is essential to stabilize leading edge protrusions in DCs and to determine directionality, since both cytoskeletal polarization and persistent chemotaxis are abrogated in the range of seconds when steady-state gradients are perturbed. In contrast to Dictyostelium amoeba, DCs are unable to decode oscillatory stimulation of soluble chemokine traveling waves into a directional response toward the wave source. These findings are consistent with the notion that DCs do not employ adaptive temporal sensing strategies that discriminate temporally increasing and decreasing chemoattractant concentrations in our setting. Taken together, in our experimental system DCs do not depend on increasing absolute chemokine concentration over time to induce persistent migration and do not integrate oscillatory stimulation. The observed capability of DCs to migrate with high directional persistence in stable gradients but not when subjected to periodic temporal cues, identifies spatial sensing as a key requirement for persistent chemotaxis of DCs

Electrical discharge coating of nanostructured TiC-Fe cermets on 304 stainless steel

The electrical discharge coating (EDC) process, as used for the development of TiC-Fe cermet coatings on 304 stainless steel, has been investigated as a function of increasing current (2–19 A) and pulse-on time (2–64 μs). Coating morphologies, comprising of a mixture of TiC, γ-Fe, ά-Fe and amorphous carbon, were characterised using the combined techniques of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD) and cross-sectional transmission electron microscopy (TEM). The developed coatings exhibited variable hardness values, up to an order of magnitude higher than that of the substrate, depending on the content and dispersion of nanostructured TiC particles within the Fe matrix. Coating hardness was found to increase with increasing current, but decrease under conditions of high pulse-on times, reflecting differences in the amount of TiC incorporated into the coatings. Optimised coatings were achieved using conditions of low processing energy which minimised the development of pores and cracks

Corrigendum to “A multi-national, multi-disciplinary Delphi consensus study on using omega-3 polyunsaturated fatty acids (n-3 PUFAs) for the treatment of major depressive disorder”. [J Affect Disord. 15 (2020) 233-238] (Journal of Affective Disorders (2020) 15 (233-238) (S0165032719319299), (10.1016/j.jad.2020.01.050))

The authors regret in the article “A multi-national, multi-disciplinary Delphi consensus study on using omega-3 polyunsaturated fatty acids (n-3 PUFAs) for the treatment of major depressive disorder” published in Journal of Affective Disorders on 15 March 2020, some information in the “6. Disclosure” section was omitted from the manuscript. This statement can now be found below. 6. Disclosures Dr. Guu has been a speaker and received speaker honorarium for Johnson & Johnson, Astra-Zeneca, Lundbeck and Hoan Pharmaceuticals, Standard Chem & Pharm, Pfizer, GSK Taiwan, ChenHua-Bio, Eli Lilly, Excelsior, Otsuka, EB Pharmaceutical and Servier – all unrelated to this work. Dr. Mischoulon has received research support from Nordic Naturals. He has provided unpaid consulting for Pharmavite LLC and Gnosis USA,Inc. He has received honoraria for speaking from the Massachusetts General Hospital Psychiatry Academy, Blackmores, Harvard Blog, and Peer Point Medical Education Institute, LLC. He has received royalties from Lippincott Williams & Wilkins for published book “Natural Medications for Psychiatric Disorders: Considering the Alternatives.” He also works with the MGH Clinical Trials Network and Institute (CTNI), which has received research funding from multiple pharmaceutical companies and NIMH. Dr. JR Hibbeln has received no honoraria and has no conflicts of interest. Dr. Sarris has received either presentation honoraria, travel support, clinical trial grants, book royalties, or independent consultancy payments from: Integria Healthcare & MediHerb, Pfizer, Scius Health, Key Pharmaceuticals, Australian Natural Therapies Group, Fiji Kava, Taki Mai, FIT-BioCeuticals, Blackmores, Soho-Flordis, Healthworld, HealthEd, HealthMasters, Kantar Consulting, Grunbiotics, Australian Natural Therapeutics Group, Research Reviews, Elsevier, Chaminade University, International Society for Affective Disorders, Complementary Medicines Australia, SPRIM, Terry White Chemists, ANS, Society for Medicinal Plant and Natural Product Research, SanofiAventis, Omega-3 center, the National Health and Medical Research Council, CR Roper Fellowship. Dr. Mcnamara has received investigator-initiated grant support from manufacturers of omega-3 fatty acid products including Martek Biosciences Inc (2007-2009), Royal DSM Nutritional Products, LLC (2013-2015), and the Inflammation Research Foundation (2008-2010), investigator-initiated grant support from Ortho-McNeil Janssen, NARSAD, and the national institutes of health (NIH), and previously served on the scientific advisory board of the Inflammation Research Foundation (2011-2013). Dr. Hamazaki received a research grant from the First Bank of Toyama Scholarship Foundation, speaking honoraria from the DHA&EPA Association, Niigata Medical Association, Toyama Medical Association, and Toyama Occupational Health Promotion Center, and a supervision fee from Otsuka Pharmaceutical Factory. Dr. Freeman (past 12 months): Investigator Initiated Trials /Research: JayMac, Sage; Advisory boards: Otsuka, Alkermes, Sunovion; Independent Data Safety and Monitoring Committee: Janssen (Johnson& Johnson). Dr. Freeman is an employee of Massachusetts General Hospital, and works with the MGH National Pregnancy Registry [Current Registry Sponsors: Teva (2018- present), Alkermes, Inc. (2016-Present); Otsuka America Pharmaceutical, Inc. (2008-Present); Forest/Actavis (2016-Present), Sunovion Pharmaceuticals, Inc. (2011-Present)]. As an employee of MGH, Dr. Freeman works with the MGH CTNI, which has had research funding from multiple pharmaceutical companies and NIMH. Dr. Maes has no conflict of interest. Dr. Matsuoka has received speaker's honoraria from Suntory, Pfizer, Mochida, Eli Lilly, Morinaga Milk, and NTT Data, and donation from Morinaga Milk and is conducting collaborative research with SUSMED and has conducted collaborative research with Morinaga Milk. Dr. RH Belmaker has no conflict of interest. Dr. Marx is currently funded by an Alfred

Three Amino Acid Mutations (F51L, T59A, and S390L) in the Capsid Protein of the Hepatitis E Virus Collectively Contribute to Virus Attenuation▿

Hepatitis E virus (HEV) is an important but extremely understudied human pathogen, and the mechanisms of HEV replication and pathogenesis are largely unknown. We previously identified an attenuated genotype 3 HEV mutant (pSHEV-1) containing three unique amino acid mutations (F51L, T59A, and S390L) in the capsid protein. To determine the role of each of these mutations, we constructed three HEV single mutants (rF51L, rT59A, and rS390L) which were all found to be replication competent in Huh7 liver cells. To determine the pathogenicities of the mutants, we utilized the specific-pathogen-free (SPF) pig model for HEV and a unique inoculation procedure that bypasses the need for propagating infectious HEV in vitro. A total of 60 pigs were intrahepatically inoculated, via an ultrasound-guided technique, with in vitro-transcribed full-length capped RNA transcripts from the infectious clones of each single mutant, the pSHEV-1 triple mutant, wild-type pSHEV-3, or phosphate-buffered saline (PBS) buffer (n = 10). The results showed that the F51L mutation partially contributed to virus attenuation, whereas the T59A and S390L mutations resulted in more drastic attenuation of HEV in pigs, as evidenced by a significantly lower incidence of viremia, a delayed appearance and shorter duration of fecal virus shedding and viremia, and lower viral loads in liver, bile, and intestinal content collected at three different necropsy times. The results indicate that the three mutations in the capsid protein collectively contribute to HEV attenuation. This study has important implications for developing a modified live-attenuated vaccine against HEV