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(1) The monocytic leukemia cell line THP-1 and primary monocyte-derived macrophages (MDMs) are popular in vitro model systems to study human innate immunity, wound healing, and tissue regeneration. However, both cell types differ significantly in their origin and response to activation stimuli. (2) Resting THP-1 and MDMs were stimulated with lipopolysaccharide (LPS) and interferon γ (IFNγ) and analyzed by Raman microspectroscopy (RM) before and 48 h after activation. Raman data were subsequently analyzed using principal component analysis. (3) We were able to resolve and analyze the spatial distribution and molecular composition of proteins, nucleic acids, and lipids in resting and activated THP-1 and MDMs. Our findings reveal that proinflammatory activation-induced significant spectral alterations at protein and phospholipid levels in THP-1. In MDMs, we identified that nucleic acid and non-membrane-associated intracellular lipid composition were also affected. (4) Our results show that it is crucial to carefully choose the right cell type for an in vitro model as the nature of the cells itself may impact immune cell polarization or activation results. Moreover, we demonstrated that RM is a sensitive tool for investigating cell-specific responses to activation stimuli and monitoring molecular changes in subcellular structures.

Objective: Coronavirus Disease 2019 (COVID-19) initially thought to be confined to the respiratory system only, is now known to be a multisystem disease. It is critical to be aware of and timely recognize neurological and neuroradiological manifestations affecting patients with COVID-19, to minimize morbidity and mortality of affected patients., Methods: We performed a retrospective chart review of patients admitted to our Level 1 trauma and stroke center during the peak of the COVID-19 outbreak in New York from March 1st to May 30, 2020, with a positive test for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) who presented mainly with neurological findings and had acute radiological brain changes on Computed Tomography (CT) scan. Patients with known chronic neurological disease processes were excluded from the study. We obtained and reviewed demographics, complete blood count, metabolic panel, D-dimer, inflammatory markers such as erythrocyte sedimentation rate (ESR), C reactive protein (CRP), imaging, and patient's hospital course. We reviewed the current literature on neuroimaging, pathophysiology, and their clinical correlations on COVID-19. This case series study was approved by our institutional review board., Result: A total of 16 patients were selected for our case series. The most common neuroimaging features on CT, were territorial to multifocal ischemic infarcts, followed by a combination of ischemia and acute white matter encephalopathic changes, followed by temporal lobe predominant focal or more generalized encephalopathy with both confluent and non-confluent patterns, isolated cortical or more extensive intracranial hemorrhages and some combination of ischemia or hemorrhage and white matter changes. All our patients had severe acute respiratory distress syndrome (ARDS), most of them had elevated inflammatory markers, and D dimer., Conclusion: COVID-19 infection is a multi-organ disease, which can manifest as rapidly progressive neurological disease beyond the more common pulmonary presentation. Early recognition of various neurological findings and neuroimaging patterns in these patients will enable timely diagnosis and rapid treatment to reduce morbidity and mortality. Our retrospective study is limited due to small non-representative sample size, strict selection criteria likely underestimating the true extent of neurological manifestations of COVID-19, mono-modality imaging technique limited to predominantly CT scans and lack of CSF analysis in all except one patient. Multi-institutional, multi-modality, largescale studies are needed with radio-pathological correlation to better understand the complete spectrum of neurologic presentations in COVID-19 patients and study the causal relationship between SARS-CoV-2 and CNS disease process., (© 2021 The Authors.)

Biomaterials play an increasing role in clinical applications and regenerative medicine. A perfectly designed biomaterial should restore the function of damaged tissue without triggering an undesirable immune response, initiate self-regeneration of the surrounding tissue and gradually degrade after implantation. The immune system is well recognized to play a major role in influencing the biocompatibility of implanted medical devices. To obtain a better understanding of the effects of biomaterials on the immune response, we have developed a highly sensitive novel test system capable of examining changes in the immune system by biomaterial. Here, we evaluated for the first time the immunopeptidome, a highly sensitive system that reflects cancer transformation, virus or drug influences and passes these cellular changes directly to T cells, as a test system to examine the effects of contact with materials. Since monocytes are one of the first immune cells reacting to biomaterials, we have tested the influence of different materials on the immunopeptidome of the monocytic THP-1 cell line. The tested materials included stainless steel, aluminum, zinc, high-density polyethylene, polyurethane films containing zinc diethyldithiocarbamate, copper, and zinc sulfate. The incubation with all material types resulted in significantly modulated peptides in the immunopeptidome, which were material-associated. The magnitude of induced changes in the immunopeptidome after the stimulation appeared comparable to that of bacterial lipopolysaccharides (LPS). The source proteins of many detected peptides are associated with cytotoxicity, fibrosis, autoimmunity, inflammation, and cellular stress. Considering all tested materials, it was found that the LPS-induced cytotoxicity-, inflammation- and cellular stress-associated HLA class I peptides were mainly induced by aluminum, whereas HLA class II peptides were mainly induced by stainless steel. These findings provide the first insights into the effects of biomaterials on the immunopeptidome. A more thorough understanding of these effects may enable the design of more biocompatible implant materials using in vitro models in future. Such efforts will provide a deeper understanding of possible immune responses induced by biomaterials such as fibrosis, inflammation, cytotoxicity, and autoimmune reactions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2020 Ghosh, Hartmann, Jakobi, März, Bichmann, Freudenmann, Mühlenbruch, Segan, Rammensee, Schneiderhan-Marra, Shipp, Stevanović and Joos.)

Epitope tagging is a versatile approach to study different proteins using a well-defined and established methodology. To date, most epitope tags such as myc, HA, V5 and FLAG tags are recognized by antibodies, which limits their use to fixed cells, tissues or protein samples. Here we introduce a broadly applicable tagging strategy utilizing a short peptide tag (PepTag) which is specifically recognized by a nanobody (PepNB). We demonstrated that the PepNB can be easily functionalized for immunoprecipitation or direct immunofluorescence staining of Pep-tagged proteins in vitro. For in cellulo studies we converted the PepNB into a fluorescently labeled Pep-chromobody (PepCB) which is functionally expressed in living cells. The addition of the small PepTag does not interfere with the examined structures in different cellular compartments and its detection with the PepCB enables optical antigen tracing in real time. By employing the phenomenon of antigen-mediated chromobody stabilization (AMCBS) using a turnover-accelerated PepCB we demonstrated that the system is suitable to visualize and quantify changes in Pep-tagged antigen concentration by quantitative live-cell imaging. We expect that this novel tagging strategy offers new opportunities to study the dynamic regulation of proteins, e.g. during cellular signaling, cell differentiation, or upon drug action.

It has been widely shown that biomaterial surface topography can modulate host immune response, but a fundamental understanding of how different topographies contribute to pro-inflammatory or anti-inflammatory responses is still lacking. To investigate the impact of surface topography on immune response, we undertook a systematic approach by analyzing immune response to eight grades of medical grade polyurethane of increasing surface roughness in three in vitro models of the human immune system. Polyurethane specimens were produced with defined roughness values by injection molding according to the VDI 3400 industrial standard. Specimens ranged from 0.1 μ m to 18  μ m in average roughness (Ra), which was confirmed by confocal scanning microscopy. Immunological responses were assessed with THP-1-derived macrophages, human peripheral blood mononuclear cells (PBMCs), and whole blood following culture on polyurethane specimens. As shown by the release of pro-inflammatory and anti-inflammatory cytokines in all three models, a mild immune response to polyurethane was observed, however, this was not associated with the degree of surface roughness. Likewise, the cell morphology (cell spreading, circularity, and elongation) in THP-1-derived macrophages and the expression of CD molecules in the PBMC model on T cells (HLA-DR and CD16), NK cells (HLA-DR), and monocytes (HLA-DR, CD16, CD86, and CD163) showed no influence of surface roughness. In summary, this study shows that modifying surface roughness in the micrometer range on polyurethane has no impact on the pro-inflammatory immune response. Therefore, we propose that such modifications do not affect the immunocompatibility of polyurethane, thereby supporting the notion of polyurethane as a biocompatible material., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2020 Sören Segan et al.)

Single-domain antibodies have emerged as highly versatile nanoprobes for advanced cellular imaging. For real-time visualization of endogenous antigens, fluorescently labelled nanobodies (chromobodies, CBs) are introduced as DNA-encoded expression constructs in living cells. Commonly, CB expression is driven from strong, constitutively active promoters. However, high expression levels are sometimes accompanied by misfolding and aggregation of those intracellular nanoprobes. Moreover, stable cell lines derived from random genomic insertion of CB-encoding transgenes bear the risk of disturbed cellular processes and inhomogeneous CB signal intensities due to gene positioning effects and epigenetic silencing. In this study we propose a strategy to generate optimized CB expressing cell lines. We demonstrate that expression as ubiquitin fusion increases the fraction of intracellularly functional CBs and identified the elongation factor 1α (EF1-α) promoter as highly suited for constitutive CB expression upon long-term cell line cultivation. Finally, we applied a CRISPR/Cas9-based gene editing approach for targeted insertion of CB expression constructs into the adeno-associated virus integration site 1 (AAVS1) safe harbour locus of human cells. Our results indicate that this combinatorial approach facilitates the generation of fully functional and stable CB cell lines for quantitative live-cell imaging of endogenous antigens.

Significantly more potent second generation 4-amino-7-chloroquinoline (4,7-ACQ) based inhibitors of the botulinum neurotoxin serotype A (BoNT/A) light chain were synthesized. Introducing an amino group at the C(3) position of the cholate component markedly increased potency (IC50 values for such derivatives ranged from 0.81 to 2.27 μM). Two additional subclasses were prepared: bis(steroidal)-4,7-ACQ derivatives and bis(4,7-ACQ)cholate derivatives; both classes provided inhibitors with nanomolar-range potencies (e.g., the Ki of compound 67 is 0.10 μM). During BoNT/A challenge using primary neurons, select derivatives protected SNAP-25 by up to 89%. Docking simulations were performed to rationalize the compounds' in vitro potencies. In addition to specific residue contacts, coordination of the enzyme's catalytic zinc and expulsion of the enzyme's catalytic water were a consistent theme. With respect to antimalarial activity, the compounds provided better IC90 activities against chloroquine resistant (CQR) malaria than CQ, and seven compounds were more active than mefloquine against CQR strain W2.

Objective: To describe an optional method for performing decompressive craniectomy using in situ hinge craniectomy technique in patients with traumatic brain injury and stroke., Methods: Sixteen patients underwent surgery for treatment of presenting pathology followed by the placement of hinge craniectomy. The technique is detailed., Results: Six patients with traumatic head injury and 10 with stroke underwent treatment of their primary pathologies with subsequent hinge craniectomy. Of these patients, more than half underwent refixation of the hinge in a minor procedure after recovery. No patient had complications related to this technique and none required further cranial decompression. In patients with intracranial pressure monitoring, all displayed values in the normal range., Conclusion: In this limited study, in situ hinge craniectomy proved useful in the treatment of patients experiencing stroke or traumatic brain injury. This procedure has the potential to eliminate the additional second incision to explant the bone flap or the refrigeration storage of the bone flap. Also, the second operation to restore the cranial contour by reimplanting the bone flap or by the creation of a cranioplasty with artificial material would not be necessary.