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Surface plasmon polaritons (SPPs) are travelling surface waves that have shown promise for applications in nanophotonics as they provide a direct route toward photon-mediated electrical signal generation – a central paradigm for speeding up and scaling down photonic elements. SPP waves have also generated fundamental interest due to their high-field strength and sub-wavelength confinement, properties that have enabled the surface-enhanced Raman effect. Over the last decade, photoemission electron microscopy (PEEM) has emerged as a pioneering technique for imaging surface electric fields through ultrashort laser pulse mediated electron emission and has therefore become an indispensable tool for characterizing plasmonic phenomena at interfaces in a variety of materials. PEEM offers nanometer spatial resolution and femtosecond temporal resolution, allowing SPPs to be prepared, monitored, and manipulated on the nanometer-femtosecond scale. Through a brief review of recent reports, we aim to introduce PEEM-based SPP imaging and manipulation modalities and highlight their utility in the context of emerging nanoscale and quantum materials science advancements.

We demonstrate control over the spatial and temporal properties of surface plasmon polaritons (SPPs) launched from nanohole arrays in silver. The arrays provide wave vector matching to allow the conversion of free-space photons into counter-propagating SPPs. SPPs launched from multiple arrays interfere at well-defined spatial positions, and the interference fringes form an all-SPP periodic nano-optical grating which evolves in space and time as the SPPs propagate. The spatio-temporal characteristics of the optical grating can be tuned through various nanohole array parameters such as tilt angle, separation, and array width. In addition, we examine multiperiodic arrays (MPAs) consisting of arrays with different pitches placed adjacent to one another. This platform allows the temporal interference of SPPs with different central wavelengths to be tailored through the MPA geometric and structural parameters. The temporal interference serves as an encoded signal, whereby the frequency components can be controlled by the array properties.

Over the past fifty years, swine models have been used for organophosphorus intoxication studies. Among these studies and others on the swine model in general, some physiological data, especially cholinesterase activity highly impacted by organophosphorus compounds like nerve agent VX, still need to be completed. To support and compare our model to others, we have published the experimental protocol, the physiological values of 31 juvenile anesthetized pigs, and the 6 h-follow-up of six supplementary anesthetized control animals and 7 VX-intoxicated pigs. We reported hemodynamics and respiratory parameters, blood levels in several biochemical parameters, blood gas, and complete blood count and compared them to the literature. We also focused on tissue and blood cholinesterase activities and detailed them for acetylcholinesterase and butyrylcholinesterase. After establishing a broad physiological data set consistent with the literature, we reported several cardio-respiratory parameters that seem more affected by an organophosphate intoxication, like heart rate, arterial blood pressure, cardiac output, and respiratory rate. Within the blood, oxygen saturation (SpO 2 ), lactatemia, base excess, and glycemia can also be measured and associated with the other parameters to evaluate the life-threatening status. This swine model is currently used to develop and evaluate medical countermeasures against organophosphate nerve agent intoxications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease, involving neuroinflammation and T cell infiltration in the central nervous system. However, the contribution of T cell responses to the pathology of the disease is not fully understood. Here we show, by flow cytometric analysis of blood and cerebrospinal fluid (CSF) samples of a cohort of 89 newly diagnosed ALS patients in Stockholm, Sweden, that T cell phenotypes at the time of diagnosis are good predictors of disease outcome. High frequency of CD4 + FOXP3 - effector T cells in blood and CSF is associated with poor survival, whereas high frequency of activated regulatory T (Treg) cells and high ratio between activated and resting Treg cells in blood are associated with better survival. Besides survival, phenotypic profiling of T cells could also predict disease progression rate. Single cell transcriptomics analysis of CSF samples shows clonally expanded CD4 + and CD8 + T cells in CSF, with characteristic gene expression patterns. In summary, T cell responses associate with and likely contribute to disease progression in ALS, supporting modulation of adaptive immunity as a viable therapeutic option., (© 2022. The Author(s).)

The transcription factor FOXP3 is essential for CD4 + FOXP3 + regulatory T (Treg) cell development and function. Human FOXP3 exists in distinct isoforms and alterations in isoform expression is associated with inflammatory disease progression, however, the exact functions of FOXP3 isoforms remain poorly understood. Herein we used flow cytometry and RNA-sequencing to analyze subsets of Treg cells from two IPEX patients, and a healthy carrier, of a recently described FOXP3 mutation (c.305delT). This mutation is located in exon 2 and results in the loss of the full-length FOXP3 isoform. Treg cells lacking full-length FOXP3 are found at lower-than-expected frequencies. This loss cannot be explained solely by altered thymic output, changes in proliferation, peripheral induction of Treg cells, or apoptosis. Instead, fulllength FOXP3 control a distinct genetic program, involving the previously identified FOXP3 regulators ID3, BCL6 and eIF4E, that upholds Treg cell lineage stability, while it appears nonessential for Treg cell activation., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Tumor-associated macrophages (TAMs) continuously fine tune their immune modulatory properties, but how gene expression programs coordinate this immune cell plasticity is largely unknown. Selective mRNA translation, controlled by MNK1/MNK2 and mTOR pathways impinging on eIF4E, facilitates reshaping of proteomes without changes in abundance of corresponding mRNAs. Using polysome profiling developed for small samples we show that, during tumor growth, gene expression in TAMs is predominately modulated via mRNA-selective changes in translational efficiencies. These alterations in gene expression paralleled accumulation of antiinflammatory macrophages with augmented phosphorylation of eIF4E, a target of the MNK1 and MNK2 kinases, known to selectively modulate mRNA translation. Furthermore, suppression of the MNK2, but not the mTOR signaling pathway, reprogrammed antiinflammatory macrophages toward a proinflammatory phenotype with the ability to activate CD8 + T cells. Thus, selective changes of mRNA translation depending on MNK2 signaling represents a key node regulating macrophage antiinflammatory functions., Competing Interests: The authors declare no competing interest.

CTLA-4 is required for CD4 + Foxp3 + regulatory T (Treg) cell function, but its mode of action remains incompletely defined. Herein we generated Ctla-4 ex2fl/fl Foxp3-Cre mice with Treg cells exclusively expressing a naturally occurring, ligand-independent isoform of CTLA-4 (liCTLA-4) that cannot interact with the costimulatory molecules CD80 and CD86. The mice did not exhibit any signs of effector T cell activation early in life, however, at 6 months of age they exhibited excessive T cell activation and inflammation in lungs. In contrast, mice with Treg cells completely lacking CTLA-4 developed lymphoproliferative disease characterized by multi-organ inflammation early in life. In vitro, Treg cells exclusively expressing liCTLA-4 inhibited CD80 and CD86 expression on dendritic cells (DC). Conversely, Treg cells required the extra-cellular part of CTLA-4 to up-regulate expression of the co-inhibitory molecule PD-L2 on DCs. Transcriptomic analysis of suppressed DCs revealed that Treg cells induced a specific immunosuppressive program in DCs., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

High-grade gliomas (HGGs) are the most aggressive and invasive primary brain tumors. The platelet-derived growth factor (PDGF) signaling pathway drives HGG progression, and enhanced expression of PDGF receptors (PDGFRs) is a well-established aberration in a subset of glioblastomas (GBMs). PDGFRA is expressed in glioma cells, whereas PDGFRB is mostly restricted to the glioma-associated stroma. Here we show that the spatial location of TAMMs correlates with the expansion of a subset of tumor cells that have acquired expression of PDGFRB in both mouse and human low-grade glioma and HCGs. Furthermore, M2-polarized microglia but not bone marrow (BM)-derived macrophages (BMDMs) induced PDGFRB expression in glioma cells and stimulated their migratory capacity. These findings illustrate a heterotypic cross-talk between microglia and glioma cells that may enhance the migratory and invasive capacity of the latter by inducing PDGFRB., (Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.)

Rationale: Regulatory T (Treg) cells suppress immune responses and have been shown to attenuate atherosclerosis. The Treg cell lineage-specification factor FOXP3 (forkhead box P3) is essential for Treg cells' ability to uphold immunologic tolerance. In humans, FOXP3 exists in several different isoforms, however, their specific role is poorly understood., Objective: To define the regulation and functions of the 2 major FOXP3 isoforms, FOXP3fl and FOXP3Δ2, as well as to establish whether their expression is associated with the ischemic atherosclerotic disease., Methods and Results: Human primary T cells were transduced with lentiviruses encoding distinct FOXP3 isoforms. The phenotype and function of these cells were analyzed by flow cytometry, in vitro suppression assays and RNA-sequencing. We also assessed the effect of activation on Treg cells isolated from healthy volunteers. Treg cell activation resulted in increased FOXP3 expression that predominantly was made up of FOXP3Δ2. FOXP3Δ2 induced specific transcription of GARP (glycoprotein A repetitions predominant), which functions by tethering the immunosuppressive cytokine TGF (transforming growth factor)-β to the cell membrane of activated Treg cells. Real-time polymerase chain reaction was used to determine the impact of alternative splicing of FOXP3 in relation with atherosclerotic plaque stability in a cohort of >150 patients that underwent carotid endarterectomy. Plaque instability was associated with a lower FOXP3Δ2 transcript usage, when comparing plaques from patients without symptoms and patients with the occurrence of recent (<1 month) vascular symptoms including minor stroke, transient ischemic attack, or amaurosis fugax. No difference was detected in total levels of FOXP3 mRNA between these 2 groups., Conclusions: These results suggest that activated Treg cells suppress the atherosclerotic disease process and that FOXP3Δ2 controls a transcriptional program that acts protectively in human atherosclerotic plaques., (© 2018 American Heart Association, Inc.)

Better identification of severe acute graft-versus-host disease (GvHD) may improve the outcome of this life-threatening complication of allogeneic hematopoietic stem cell transplantation. GvHD induces tissue damage and the release of damage-associated molecular pattern (DAMP) molecules. Here, we analyzed GvHD patients ( n = 39) to show that serum heat shock protein glycoprotein 96 (Gp96) could be such a DAMP molecule. We demonstrate that serum Gp96 increases in gastrointestinal GvHD patients and its level correlates with disease severity. An increase in Gp96 serum level was also observed in a mouse model of acute GvHD. This model was used to identify complement C3 as a main partner of Gp96 in the serum. Our biolayer interferometry, yeast two-hybrid and in silico modeling data allowed us to determine that Gp96 binds to a complement C3 fragment encompassing amino acids 749-954, a functional complement C3 hot spot important for binding of different regulators. Accordingly, in vitro experiments with purified proteins demonstrate that Gp96 downregulates several complement C3 functions. Finally, experimental induction of GvHD in complement C3-deficient mice confirms the link between Gp96 and complement C3 in the serum and with the severity of the disease., Competing Interests: Conflict of interest: The authors have declared that no conflict of interest exists.

CD4(+)FOXP3(+) regulatory T (Treg) cells are essential for maintaining immunological self-tolerance. Treg cell development and function depend on the transcription factor FOXP3, which is present in several distinct isoforms due to alternative splicing. Despite the importance of FOXP3 in the proper maintenance of Treg cells, the regulation and functional consequences of FOXP3 isoform expression remains poorly understood. Here, we show that in human Treg cells IL-1β promotes excision of FOXP3 exon 7. FOXP3 is not only expressed by Treg cells but is also transiently expressed when naïve T cells differentiate into Th17 cells. Forced splicing of FOXP3 into FOXP3Δ2Δ7 strongly favored Th17 differentiation in vitro. We also found that patients with Crohn's disease express increased levels of FOXP3 transcripts lacking exon 7, which correlate with disease severity and IL-17 production. Our results demonstrate that alternative splicing of FOXP3 modulates T cell differentiation. These results highlight the importance of characterizing FOXP3 expression on an isoform basis and suggest that immune responses may be manipulated by modulating the expression of FOXP3 isoforms, which has broad implications for the treatment of autoimmune diseases.

The forkhead/winged-helix transcription factor FOXP3 confers suppressive ability to CD4(+)FOXP3(+) regulatory T (Treg) cells. Human Treg cells express several different isoforms of FOXP3 that differ in function. However, the regulation and functional consequences of FOXP3 isoform expression remains poorly understood. In order to study the function of the FOXP3Δ2Δ7 isoform in vivo we generated mice that exclusively expressed a Foxp3 isoform lacking exon 2 and 7. These mice exhibited multi-organ inflammation, increased cytokine production, global T cell activation, activation of antigen-presenting cells and B cell developmental defects, all features that are shared with mice completely deficient in FOXP3. Our results demonstrate that the mouse counterpart of human FOXP3Δ2Δ7 is unable to confer suppressive ability to Treg cells., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

With the increasing interest in clinical trials with regulatory T cells (Tregs), immunological profiling of prospective target groups and standardized procedures for Treg isolation are needed. In this study, flow cytometry was used to assess peripheral blood lymphocyte profiles of young healthy individuals and patients undergoing haemodialysis treatment. Tregs obtained from the former may be used in haematopoietic stem cell transplantation and Tregs from the latter in the prevention of kidney transplant rejection. FOXP3 mRNA expression with accompanying isoform distribution was also assessed by the quantitative reverse transcriptase polymerase chain reaction. Flow-cytometric gating strategies were systematically analysed to optimize the isolation of Tregs. Our findings showed an overall similar immunological profile of both cohorts in spite of great differences in both age and health. Analysis of flow-cytometric gating techniques highlighted the importance of gating for both CD25high and CD127low expression in the isolation of FOXP3-positive cells. This study provides additional insight into the immunological profile of young healthy individuals and uraemic patients as well as in-depth analysis of flow-cytometric gating strategies for Treg isolation, supporting the development of Treg therapy using cells from healthy donors and uraemic patients., (© 2015 John Wiley & Sons Ltd.)

The heat-shock protein 27 (HSP27) is up-regulated in tumor cells and released in their microenvironment. Here, we show that extracellular HSP27 has a proangiogenic effect evidenced on chick chorioallantoic membrane. To explore this effect, we test the recombinant human protein (rhHSP27) at physiopathological doses (0.1-10 μg/ml) onto human microvascular endothelial cells (HMECs) grown as monolayers or spheroids. When added onto HMECs, rhHSP27 dose-dependently accelerates cell migration (with a peak at 5 μg/ml) and favors spheroid sprouting within 12-24 h. rhHSP27 increases VEGF gene transcription and promotes secretion of VEGF-activating VEGF receptor type 2. Increased VEGF transcription is related to NF-κB activation in 30 min. All of these effects are initiated by rhHSP27 interaction with Toll-like receptor 3 (TLR3). Such an interaction can be detected by immunoprecipitation but does not seem to be direct, as we failed to detect an interaction between rhHSP27 and monomeric TLR3 by SPR analysis. rhHSP27 is rapidly internalized with a pool of TLR3 to the endosomal compartment (within 15-30 min), which is required for NF-κB activation in a cytosolic Ca(2+)-dependent manner. The HSP27/TLR3 interaction induces NF-κB activation, leading to VEGF-mediated cell migration and angiogenesis. Such a pathway provides alternative targets for antiangiogenic cancer therapy.

First discovered in 1962, heat shock proteins (HSPs) are highly studied with about 35,500 publications on the subject to date. HSPs are highly conserved, function as molecular chaperones for a large panel of "client" proteins and have strong cytoprotective properties. Induced by many different stress signals, they promote cell survival in adverse conditions. Therefore, their roles have been investigated in several conditions and pathologies where HSPs accumulate, such as in cancer. Among the diverse mammalian HSPs, some members share several features that may qualify them as cancer biomarkers. This review focuses mainly on three inducible HSPs: HSP27, HPS70, and HSP90. Our survey of recent literature highlights some recurring weaknesses in studies of the HSPs, but also identifies findings that indicate that some HSPs have potential as cancer biomarkers for successful clinical applications.

Heat shock proteins (HSPs) are necessary for cancer cell survival. We identified a mutant of HSP110 (HSP110ΔE9) in colorectal cancer showing microsatellite instability (MSI CRC), generated from an aberrantly spliced mRNA and lacking the HSP110 substrate-binding domain. This mutant was expressed at variable levels in almost all MSI CRC cell lines and primary tumors tested. HSP110ΔE9 impaired both the normal cellular localization of HSP110 and its interaction with other HSPs, thus abrogating the chaperone activity and antiapoptotic function of HSP110 in a dominant-negative manner. HSP110ΔE9 overexpression caused the sensitization of cells to anticancer agents such as oxaliplatin and 5-fluorouracil, which are routinely prescribed in the adjuvant treatment of people with CRC. The survival and response to chemotherapy of subjects with MSI CRCs was associated with the tumor expression level of HSP110ΔE9. HSP110 may thus constitute a major determinant for both prognosis and treatment response in CRC.

Stress or heat shock proteins (HSPs) 70 and 90 are powerful chaperones whose expression is induced in response to a wide variety of physiological and environmental insults. These proteins have different functions depending on their intracellular or extracellular location. Intracellular HSPs have a protective function. They allow the cells to survive potentially lethal conditions. The cytoprotective functions of HSPs can largely be explained by their anti-apoptotic properties. HSP70 and HSP90 can directly interact with different proteins of the tightly regulated programmed cell death machinery and thereby block the apoptotic process at distinct key points. In cancer cells, where the expression of HSP70 and/or HSP90 is frequently abnormally high, they participate in oncogenesis and in resistance to chemotherapy. Therefore, the inhibition of HSPs has become an interesting strategy in cancer therapy. In contrast to intracellular HSPs, extracellularly located or membrane-bound HSPs mediate immunological functions. They can elicit an immune response providing a link between innate and adaptive immune systems. In cancer, most immunotherapeutical approaches based on extracellular HSPs exploit their carrier function for immunogenic peptides. This review will focus on the roles of HSP70 and HSP90 in apoptosis and in innate immunity and how these functions are being exploited in cancer therapy., ((c) 2010 S. Karger AG, Basel.)

Heat shock protein 27 (HSP27) accumulates in stressed cells and helps them to survive adverse conditions. We have already shown that HSP27 has a function in the ubiquitination process that is modulated by its oligomerization/phosphorylation status. Here, we show that HSP27 is also involved in protein sumoylation, a ubiquitination-related process. HSP27 increases the number of cell proteins modified by small ubiquitin-like modifier (SUMO)-2/3 but this effect shows some selectivity as it neither affects all proteins nor concerns SUMO-1. Moreover, no such alteration in SUMO-2/3 conjugation is achievable by another HSP, such as HSP70. Heat shock factor 1 (HSF1), a transcription factor responsible for HSP expression, is one of the targets of HSP27. In stressed cells, HSP27 enters the nucleus and, in the form of large oligomers, binds to HSF1 and induces its modification by SUMO-2/3 on lysine 298. HSP27-induced HSF1 modification by SUMO-2/3 takes place downstream of the transcription factor phosphorylation on S303 and S307 and does not affect its DNA-binding ability. In contrast, this modification blocks HSF1 transactivation capacity. These data show that HSP27 exerts a feedback inhibition of HSF1 transactivation and enlighten the strictly regulated interplay between HSPs and HSF1. As we also show that HSP27 binds to the SUMO-E2-conjugating enzyme, Ubc9, our study raises the possibility that HSP27 may act as a SUMO-E3 ligase specific for SUMO-2/3.

Stress or heat shock proteins (Hsps) Hsp90, Hsp70 and Hsp27 are chaperones that assist the proteins in their folding, stability, assembly into multi-protein complexes and transport across cellular membranes. The expression of some of them is highly induced in response to a wide variety of physiological and environmental insults. Hsps have a dual function depending on their intracellular or extracellular location. Intracellular Hsps have a protective function. They allow the cells to survive to lethal conditions. The cytoprotective functions of Hsps can largely explain by their anti-apoptotic properties. Hsp90, Hsp70 and Hsp27 can directly interact with different proteins of the tightly regulated programmed cell death machinery and thereby block the apoptotic process at distinct key points. In cancer cells, where the expression of Hsp27, Hsp70 and/or Hsp90 is frequently abnormally high, they participate in oncogenesis and in resistance to chemotherapy. Therefore, the inhibition of Hsps has become an interesting strategy in cancer therapy. In contrast to intracellular Hsps, extracellular located or membrane-bound Hsps mediate immunological functions. They can elicit an immune response modulated either by the adaptive or innate immune system. In cancer, most immunotherapeutical approaches based on extracellular Hsps exploit their carrier function for immunogenic peptides. This review will discuss this different and often paradoxical approaches in cancer therapy based on the dual role of Hsps, protective/tumorigenic versus immunogenic.