Photodynamic Effects with 5-Aminolevulinic Acid on Cytokines and Exosomes in Human Peripheral Blood Mononuclear Cells from Patients with Crohn's Disease.

Photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA) which is the precursor of the photosensitizer protoporphyrin IX (PpIX) is an available treatment for several diseases. ALA-PDT induces the apoptosis and necrosis of target lesions. We have recently reported the effects of ALA-PDT on cytokines and exosomes of human healthy peripheral blood mononuclear cells (PBMCs). This study has investigated the ALA-PDT-mediated effects on PBMC subsets from patients with active Crohn's disease (CD). No effects on lymphocyte survival after ALA-PDT were observed, although the survival of CD3-/CD19+ B-cells seemed slightly reduced in some samples. Interestingly, ALA-PDT clearly killed monocytes. The subcellular levels of cytokines and exosomes associated with inflammation were widely downregulated, which is consistent with our previous findings in PBMCs from healthy human subjects. These results suggest that ALA-PDT may be a potential treatment candidate for CD and other immune-mediated diseases.

BMPR2 inhibits activin and BMP signaling via wild-type ALK2.

TGF-ß/BMP superfamily ligands require heteromeric complexes of type 1 and 2 receptors for ligand-dependent downstream signaling. Activin A, a TGF-ß superfamily member, inhibits growth of multiple myeloma cells, but the mechanism for this is unknown. We therefore aimed to clarify how activins affect myeloma cell survival. Activin A activates the transcription factors SMAD2/3 through the ALK4 type 1 receptor, but may also activate SMAD1/5/8 through mutated variants of the type 1 receptor ALK2 (also known as ACVR1). We demonstrate that activin A and B activate SMAD1/5/8 in myeloma cells through endogenous wild-type ALK2. Knockdown of the type 2 receptor BMPR2 strongly potentiated activin A- and activin B-induced activation of SMAD1/5/8 and subsequent cell death. Furthermore, activity of BMP6, BMP7 or BMP9, which may also signal via ALK2, was potentiated by knockdown of BMPR2. Similar results were seen in HepG2 liver carcinoma cells. We propose that BMPR2 inhibits ALK2-mediated signaling by preventing ALK2 from oligomerizing with the type 2 receptors ACVR2A and ACVR2B, which are necessary for activation of ALK2 by activins and several BMPs. In conclusion, BMPR2 could be explored as a possible target for therapy in patients with multiple myeloma.This article has an associated First Person interview with the first author of the paper.

Comparison between 8-methoxypsoralen and 5-aminolevulinic acid in killing T cells of photopheresis patients ex vivo.

BACKGROUND AND OBJECTIVE: Extracorporeal photopheresis (ECP), an established modality for cutaneous T-cell lymphoma (CTCL) and graft-versus-host disease, involves ex vivo treatment of isolated leukocytes of a patient with the photosensitizing drug 8-methoxypsoralen (8-MOP) and ultraviolet-A (UV-A) exposure before reinfusion back to the patient. However, 8-MOP binds to both diseased and normal cells and thus kills both types of the cells after UV-A illumination with little selectivity. Clinically, this modality gives only partial response in the majority of treated patients. 5-Aminolevulinic acid (5-ALA), a precursor of the potent photosensitizer protoporphyrin IX (PpIX), has been shown to selectively induce PpIX in activated T lymphocytes (T cells) and could be an alternative for 8-MOP. The objectives of this study were to investigate ex vivo 5-ALA dark toxicity, 5-ALA-induced PpIX production, and photodynamic effect on T cells obtained from clinical ECP patients after the treatment of 5-ALA or 8-MOP plus a built-in certified UV-A source in the commercial Therakos™ Photopheresis System. MATERIALS AND METHODS: Flow cytometry was used to study dark cytotoxic effects of 5-ALA on human leukocytes, to measure the production of 5-ALA-induced PpIX in CD25+ activated T cells from both diluted mononuclear cells and undiluted buffy coat samples of ECP patients and to compare photodynamic effects on CD4+ and CD8+ T cells with 5-ALA/UV-A or 8-MOP/UV-A. RESULTS: No dark toxicity of 5-ALA on the leukocytes of ECP patients was seen at concentrations up to 10 mM for an incubation of up to 20 hours. 5-ALA-induced PpIX was produced more in CD25+ activated T cells than resting T cells in both diluted mononuclear cells and undiluted buffy coat samples, although there was a huge variation of samples from different individual patients. The CD4+ and CD8+ T cells treated with 5-ALA/UV-A were killed more than those treated with 8-MOP/UV-A. CONCLUSION: These results suggest that 5-ALA/UV-A may have the potential for improving the efficacy of ECP. Lasers Surg. Med. 50:469-475, 2018. © 2018 Wiley Periodicals, Inc.

Identification of two independent nucleosome-binding domains in the transcriptional co-activator SPBP.

Transcriptional regulation requires co-ordinated action of transcription factors, co-activator complexes and general transcription factors to access specific loci in the dense chromatin structure. In the present study we demonstrate that the transcriptional co-regulator SPBP [stromelysin-1 PDGF (platelet-derived growth factor)-responsive element binding protein] contains two independent chromatin-binding domains, the SPBP-(1551-1666) region and the C-terminal extended PHD [ePHD/ADD (extended plant homeodomain/ATRX-DNMT3-DNMT3L)] domain. The region 1551-1666 is a novel core nucleosome-interaction domain located adjacent to the AT-hook motif in the DNA-binding domain. This novel nucleosome-binding region is critically important for proper localization of SPBP in the cell nucleus. The ePHD/ADD domain associates with nucleosomes in a histone tail-dependent manner, and has significant impact on the dynamic interaction between SPBP and chromatin. Furthermore, SPBP and its homologue RAI1 (retinoic-acid-inducible protein 1), are strongly enriched on chromatin in interphase HeLa cells, and both proteins display low nuclear mobility. RAI1 contains a region with homology to the novel nucleosome-binding region SPBP-(1551-1666) and an ePHD/ADD domain with ability to bind nucleosomes. These results indicate that the transcriptional co-regulator SPBP and its homologue RAI1 implicated in Smith-Magenis syndrome and Potocki-Lupski syndrome both belong to the expanding family of chromatin-binding proteins containing several domains involved in specific chromatin interactions.

Photodynamic Effects with 5-Aminolevulinic Acid on Cytokines and Exosomes in Human Peripheral Blood Mononuclear Cells.

Photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA), a precursor to the potent photosensitizer, protoporphyrin IX (PpIX), is an established modality for several malignant and premalignant diseases. This treatment is based on the light-activated PpIX in targeted lesions. Although numerous studies have confirmed the necrosis and apoptosis involved in the mechanism of action of this modality, little information is available for the change of exosome levels after treatment. We report from the first study on the effects of ALA-PDT on cytokines and exosomes of human healthy peripheral blood mononuclear cells (PBMCs). The treatment reduced the cytokines and exosomes studied, although there was variation among individual PBMC samples. This reduction is consistent with PDT-mediated survivals of subsets of PBMCs. More specifically, the ALA-PDT treatment apparently decreased all pro-inflammatory cytokines included, suggesting that this treatment may provide a strong anti-inflammatory effect. In addition, the treatment has decreased the levels of different types of exosomes, the HLA-DRDPDQ exosome in particular, which plays an important role in the rejection of organ transplantation as well as autoimmune diseases. These results may suggest future therapeutic strategies of ALA-PDT.

Selective Killing of Activated T Cells by 5-Aminolevulinic Acid Mediated Photodynamic Effect: Potential Improvement of Extracorporeal Photopheresis.

Extracorporeal photopheresis (ECP), a modality that exposes isolated leukocytes to the photosensitizer 8-methoxypsoralen (8-MOP) and ultraviolet-A (UV-A) light, is used to treat conditions such as cutaneous T-cell lymphoma and graft-versus-host disease. However, the current procedure of ECP has limited selectivity and efficiency; and produces only partial response in the majority of treated patients. Additionally, the treatment is expensive and time-consuming, so the improvement for this modality is needed. In this study, we used the concept of photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA), a precursor of an endogenously synthesized photosensitizer protoporphyrin IX (PpIX) in combination with blue light to explore the possibility of targeting activated human blood T cells ex vivo. With various T-cell activation protocols, a high ALA-induced PpIX production took place in activated CD3+, CD4+CD25+, and CD8+ T cell populations with their subsequent killing after blue light exposure. By contrast, resting T cells were much less damaged by the treatment. The selective and effective killing effect on the activated cells was also seen after co-cultivating activated and resting T cells. Under our clinically relevant experimental conditions, ALA-PDT killed activated T cells more selectively and efficiently than 8-MOP/UV-A. Monocyte-derived dendritic cells (DCs) were not affected by the treatment. Incubation of ALA-PDT damaged T cells with autologous DCs induced a downregulation of the co-stimulatory molecules CD80/CD86 and also upregulation of interleukin 10 (IL-10) and indoleamine 2,3-dioxygenase expression, two immunosuppressive factors that may account for the generation of tolerogenic DCs. Overall, the data support the potential use of ALA-PDT strategy for improving ECP by selective and effective killing of activated T cells and induction of immune tolerance.

Hydroxychloroquine potentiates carfilzomib toxicity towards myeloma cells.

Cells degrade proteins either by proteasomes that clinically are targeted by for example bortezomib or carfilzomib, or by formation of autophagosomes and lysosomal degradation that can be inhibited by hydroxychloroquine (HCQ). Multiple myeloma is unique among cancers because proteasomal inhibition has good clinical effects. However, some multiple myeloma patients display intrinsic resistance to the treatment and most patients acquire resistance over time. We hypothesized that simultaneous targeting both arms of protein degradation could be a way to improve treatment of multiple myeloma. Here we tested the combined effects of the lysosomal inhibitor HCQ and clinically relevant proteasome inhibitors on myeloma cell lines and primary cells. Carfilzomib and bortezomib both induced immunoglobulin-containing aggregates in myeloma cells. HCQ significantly potentiated the effect of carfilzomib in both cell lines and in primary myeloma cells. In contrast, HCQ had little or no effects on the toxicity of bortezomib. Furthermore, cells adapted to tolerate high levels of carfilzomib could be re-sensitized to the drug by co-treatment with HCQ. Thus, we show that inhibition of lysosomal degradation can overcome carfilzomib resistance, suggesting that the role of autophagy in myeloma cells is dependent on type of proteasome inhibitor. In conclusion, attempts should be made to combine HCQ with carfilzomib in the treatment of multiple myeloma.

SPBP is a sulforaphane induced transcriptional coactivator of NRF2 regulating expression of the autophagy receptor p62/SQSTM1.

Organisms exposed to oxidative stress respond by orchestrating a stress response to prevent further damage. Intracellular levels of antioxidant agents increase, and damaged components are removed by autophagy induction. The KEAP1-NRF2 signaling pathway is the main pathway responsible for cell defense against oxidative stress and for maintaining the cellular redox balance at physiological levels. Sulforaphane, an isothiocyanate derived from cruciferous vegetables, is a potent inducer of KEAP1-NRF2 signaling and antioxidant response element driven gene expression. In this study, we show that sulforaphane enhances the expression of the transcriptional coregulator SPBP. The expression curve peaks 6-8 hours post stimulation, and parallels the sulforaphane-induced expression of NRF2 and the autophagy receptor protein p62/SQSTM1. Reporter gene assays show that SPBP stimulates the expression of p62/SQSTM1 via ARE elements in the promoter region, and siRNA mediated knock down of SPBP significantly decreases the expression of p62/SQSTM1 and the formation of p62/SQSTM1 bodies in HeLa cells. Furthermore, SPBP siRNA reduces the sulforaphane induced expression of NRF2, and the expression of the autophagy marker protein LC3B. Both these proteins contain ARE-like elements in their promoter regions. Over-expressed SPBP and NRF2 acts synergistically on the p62/SQSTM1 promoter and colocalize in nuclear speckles in HeLa cells. Collectively, these results suggest that SPBP is a coactivator of NRF2, and hence may be important for securing enhanced and sustained expression of NRF2 induced genes such as proteins involved in selective autophagy.

A phylogenetic study of SPBP and RAI1: evolutionary conservation of chromatin binding modules.

Our genome is assembled into and array of highly dynamic nucleosome structures allowing spatial and temporal access to DNA. The nucleosomes are subject to a wide array of post-translational modifications, altering the DNA-histone interaction and serving as docking sites for proteins exhibiting effector or "reader" modules. The nuclear proteins SPBP and RAI1 are composed of several putative "reader" modules which may have ability to recognise a set of histone modification marks. Here we have performed a phylogenetic study of their putative reader modules, the C-terminal ePHD/ADD like domain, a novel nucleosome binding region and an AT-hook motif. Interactions studies in vitro and in yeast cells suggested that despite the extraordinary long loop region in their ePHD/ADD-like chromatin binding domains, the C-terminal region of both proteins seem to adopt a cross-braced topology of zinc finger interactions similar to other structurally determined ePHD/ADD structures. Both their ePHD/ADD-like domain and their novel nucleosome binding domain are highly conserved in vertebrate evolution, and construction of a phylogenetic tree displayed two well supported clusters representing SPBP and RAI1, respectively. Their genome and domain organisation suggest that SPBP and RAI1 have occurred from a gene duplication event. The phylogenetic tree suggests that this duplication has happened early in vertebrate evolution, since only one gene was identified in insects and lancelet. Finally, experimental data confirm that the conserved novel nucleosome binding region of RAI1 has the ability to bind the nucleosome core and histones. However, an adjacent conserved AT-hook motif as identified in SPBP is not present in RAI1, and deletion of the novel nucleosome binding region of RAI1 did not significantly affect its nuclear localisation.