[Show abstract][Hide abstract] ABSTRACT: One of the major controversies of contemporary medicine is created by an increased consumption of nicotine and growing evidence of its connection to cancer, which urges elucidation of the molecular mechanisms of oncogenic effects of inhaled nicotine. Current research indicates that nicotinergic regulation of cell survival and death is more complex than originally thought, because it involves signals emanating from both cell membrane (cm)- and mitochondrial (mt)-nicotinic acetylcholine receptors (nAChRs). In this study, we elaborated on the novel concept linking cm-nAChRs to growth promotion of lung cancer cells through cooperation with the growth factor signaling, and mt-nAChRs — to inhibition of intrinsic apoptosis through prevention of opening of mitochondrial permeability transition pore (mPTP).
Experiments were performed with normal human lobar bronchial epithelial cells, the lung squamous cell carcinoma line SW900, and intact and NNK-transformed immortalized human bronchial cell line BEP2D.
We demonstrated that the growth-promoting effect of nicotine mediated by activation of α7 cm-nAChR synergizes mainly with that of epidermal growth factor (EGF), α3 — vascular endothelial growth factor (VEGF), α4 — insulin-like growth factor I (IGF-I) and VEGF, whereas α9 with EGF, IGF-I and VEGF. We also established the ligand-binding abilities of mt-nAChRs and demonstrated that quantity of the mt-nAChRs coupled to inhibition of mPTP opening increases upon malignant transformation.
These results indicated that the biological sum of simultaneous activation of cm- and mt-nAChRs produces a combination of growth-promoting and anti-apoptotic signals that implement the tumor-promoting action of nicotine on lung cells. Therefore, nAChRs may be a promising molecular target to arrest lung cancer progression and re-open mitochondrial apoptotic pathways.
BMC Cancer 12/2015; 15(1). DOI:10.1186/s12885-015-1158-4 · 3.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This special issue of International Immunopharmacology is the proceedings of the Fourth International Symposium on Non-neuronal Acetylcholine that was held on August 28-30, 2014 at the Justus Liebig University of Giessen in Germany. It contains original contributions of meeting participants covering the significant progress in understanding of the biological and medical significance of the non-neuronal cholinergic system extending from exciting insights into molecular mechanisms regulating this system via miRNAs over the discovery of novel cholinergic cellular signaling circuitries to clinical implications in cancer, wound healing, immunity and inflammation, cardiovascular, respiratory and other diseases.
International immunopharmacology 09/2015; DOI:10.1016/j.intimp.2015.08.023 · 2.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pemphigus vulgaris (PV) is a life-long, potentially fatal IgG autoantibody-mediated blistering disease targeting mucocutaneous keratinocytes (KCs). PV patients develop pathogenic anti-desmoglein (Dsg) 3 ± 1 and anti-mitochondrial antibodies (AMA), but it remained unknown if and how AMA enter KCs and why other cell types are not affected in PV. Therefore, we sought to elucidate mechanisms of cell entry, trafficking and pathogenic action of AMA in PV. We found that PVIgGs associated with FcRn on the cell membrane, the PVIgG-FcRn complexes entered KCs, and reached mitochondria where they dissociated. The liberated AMA altered mitochondrial membrane potential, respiration, ATP production, and induced cytochrome c release, while the lack or inactivation of FcRn abolished the ability of PVIgG to reach and damage mitochondria, and to cause detachment of KCs. The assays of mitochondrial functions and keratinocyte adhesion demonstrated that while the pathobiological effects of AMA on KCs are reversible, they become irreversible, leading to epidermal blistering (acantholysis), when AMA synergize with anti-desmoglein (Dsg) antibodies. Thus, it appears that AMA enter a keratinocyte in a complex with FcRn, become liberated from the endosome in the cytosol, and are trafficked to the mitochondria, wherein they trigger pro-apoptotic events leading to shrinkage of basal KCs uniquely expressing FcRn in epidermis. During recovery, KCs extend their cytoplasmic aprons toward neighboring cells, but anti-Dsg antibodies prevent assembly of nascent desmosomes due to steric hindrance, thus rendering acantholysis irreversible. In conclusion, FcRn is a common acceptor protein for internalization of AMA and, perhaps, for PV autoantibodies to other intracellular antigens, and PV is a novel disease paradigm for investigating and elucidating the role of FcRn in this autoimmune disease and possibly other autoimmune diseases.
Journal of Biological Chemistry 08/2015; DOI:10.1074/jbc.M115.668061 · 4.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Modern research of molecular mechanisms of keratinocyte detachment in patients with autoimmune bullous dermatoses has revealed, rather unexpectedly, the potential role of mitochondrial dysfunction. In this issue of the journal, an important study by Hirose et al (1) demonstrates for the first time that polymorphisms in the mitochondrially encoded ATP synthase 8 gene are associated with susceptibility to bullous pemphigoid (BP). The authors analyzed large cohorts of BP patients and unrelated healthy individuals from Germany and found that among 19 non-synonymous SNPs, the A-allele at nt8519 was statistically significantly increased in BP patients. On the one hand, these findings are in keeping with the notion that mutations in MT-ATP8 gene increase susceptibility to autoimmunity in both humans and mice, and, on the other hand - with increased susceptibility to target cell damage by reactive oxygen species (ROS) elevated in cells carrying an MT-ATP8 mutation (see references cited in Hirose et al (1)). This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Immunobullous diseases mediated by IgA are often difficult to manage, but to date no mechanism has been proposed. Rituximab is an anti-CD20 monoclonal antibody that has demonstrated good efficacy in the treatment of refractory mucous membrane pemphigoid. However, not all cases of mucous membrane pemphigoid respond to rituximab. Herein we present a case of treatment-refractory mucous membrane pemphigoid and propose a mechanism to explain the lack of response to therapy.
Before treatment, direct immunofluorescent examination of a biopsy sample from the patient's perilesional skin demonstrated linear deposition of IgG and IgA along the dermoepidermal junction. After a multidrug immunosuppressive regimen that included rituximab, results of a second biopsy demonstrated only IgA along the dermoepidermal junction. This finding correlated well with flow cytometry data from the same patient that demonstrated a persistent population of IgA-secreting plasmablasts/plasma cells, despite depletion of CD20+ cells. In addition, results of immunohistochemical analysis of the perilesional skin remained positive for CD19 and CD138 immune cells (plasmablast/plasma cell markers).
These findings suggest that current available immunosuppressive medications, including rituximab, cannot eliminate IgA-secreting plasmablasts/plasma cells, which are likely central to the pathophysiology of IgA-mediated immunobullous diseases. Future studies are needed to develop alternative therapeutic strategies that target autoreactive IgA-secreting plasmablasts/plasma cells.
[Show abstract][Hide abstract] ABSTRACT: Cutaneous lupus erythematosus (CLE) is a chronic inflammatory autoimmune skin disease. Evidence-based therapy for CLE is lacking in the most part. Intravenous immunoglobulin (IVIg) is being increasingly utilized as off-label therapy for a variety of autoimmune and inflammatory conditions, especially in dermatology. The usefulness of IVIg in CLE is not well established. The goal of the present study was to obtain the proof-of-concept evidence that IVIg can control acute CLE and thus replace current systemic immunosuppressive therapy that causes severe side effects and adverse reactions. Sixteen patients who tried and failed various systemic treatments for CLE were screened and consented to use IVIg as a monotherapy. The IVIg was administered at 500 mg/kg/day on 4 consecutive days up to a total of 2 g/kg/month for 3 months, and the subjects were monitored for additional 6 months off any drug for a possible relapse. The cumulative results revealed an overall improvement, as evinced by a decrease of both objective and subjective measures of disease activity. The most sensitive and specific objective and subjective instruments for assessment of the therapeutic effect of IVIg were CLASI-A (Cutaneous Lupus Erythematosus Disease Area and Severity Index) measuring disease activity and Skindex-29 scores, respectively. The CLASI-A score dropped down from the initial value taken as 100%, and remained in the range of approximately 70% until the last visit. Three patients (18.8%) had a temporary flare of CLE symptoms but recovered within a month from the relapse. No serious side effects and adverse reactions occurred. Thus, IVIg monotherapy in CLE allowed to achieve: i) rapid and persistent decreased in disease activity; ii) steady improvement of patients' quality of life assessed by Skindex-29; iii) low relapse rate; and iv) mild nature and short duration of relapses. Since healing was maintained for months after IVIg treatment, it is possible that the IVIgtriggered molecular events mediating the therapeutic action of IVIg that continued to unfold after the end of therapy.
[Show abstract][Hide abstract] ABSTRACT: Purpose:
Because cholinergic drugs are used in ophthalmology and cholinergic stimulation has been shown to facilitate epithelialization of mucocutaneous wounds, we performed a systematic analysis of components of the cholinergic network of human and murine corneal epithelial cells (CECs) and determined the role of autocrine and paracrine acetylcholine (ACh) in regulation of CEC motility.
We investigated the expression of ACh receptors at the mRNA and protein levels in human immortalized CECs, localization of cholinergic molecules in normal and wounded murine cornea, and the effects of cholinergic drugs on CEC directional and random migration in vitro, intercellular adhesion, and expression of integrin αV and E-cadherin.
We demonstrated that corneal epithelium expresses the ACh-synthesizing enzyme choline acetyltransferase, the ACh-degrading enzyme acetylcholinesterase, two muscarinic ACh receptors (mAChRs), M3 and M4, and several nicotinic ACh receptors (nAChRs), including both α7- and α9-made homomeric nAChRs and predominantly the α3β2±α5 subtype of heteromeric nAChRs. Wounding affected the expression patterns of cholinergic molecules in the murine corneal epithelium. Constant stimulation of CECs through both muscarinic and nicotinic signaling pathways was essential for CEC survival and both directional and random migration in vitro. Both α7 and non-α7 nAChRs elicited chemotaxis, with the α7 signaling exhibiting a stronger chemotactic effect. Cholinergic stimulation of CECs upregulated expression of the integrin and cadherin molecules involved in epithelialization. We found synergy between the proepithelialization signals elicited by different ACh receptors expressed in CECs.
Simultaneous stimulation of mAChRs and nAChRs by ACh may be required to synchronize and balance ionic and metabolic events in a single cell. Localization of these cholinergic enzymes and receptors in murine cornea indicated that the concentration of endogenous ACh and the mode of its signaling differ among corneal epithelial layers. Elucidation of the signaling events elicited upon agonist binding to corneal mAChRs and nAChRs will be crucial for understanding the mechanisms of ACh signaling in CECs, which has salient clinical implications.
[Show abstract][Hide abstract] ABSTRACT: Abstract: Elevated levels of histone deacetylases (HDACs) have been indicated in the development of some cancers. HDAC has been imaged using 18F-FAHA and may serve as a marker to study epigenetics. We report evaluation of 18F-FAHA as a probe in the early diagnosis of lung cancer using 18F-FAHA PET/CT studies of A/J mice treated with NNK. 18F-FAHA radiosynthesis was carried out in specific activity of ~2 Ci/μmol. A/J mice were divided into 2 groups: 1. Controls; 2. NNK treatment group with NNK (100 mg/kg, ip, weekly for 4 wks). Mice were injected 100-200 μCi i.v. 18F-FAHA and then scanned in Inveon PET/CT under anesthesia using 2.0% isoflurane. Midbrain, cerebellum and brainstem uptake of 18F-FAHA was displaced by the known HDAC inhibitor, suberanilohydroxamic acid (SAHA) with less than 10% activity remaining. CT revealed presence of lung nodules in 8 to 10-month old NNK mice while control mice were free of tumors. Little uptake of 18F-FAHA was observed in the control mice lungs while significant 18F-FAHA uptake occurred in the lungs of NNK-treated mice with tumor/nontumor >2.0. Ex vivo scans of the excised NNK and control mice lungs confirmed presence of extensive amounts of lung nodules seen by CT and confirmed by 18F-FAHA in the NNK mice with tumor/nontumor >6.0. Our preliminary imaging studies with A/J mice lung cancer model suggest 18F-FAHA PET may allow the study of epigenetic mechanisms involved in NNK-induced tumorigenesis in the lungs.
American Journal of Nuclear Medicine and Molecular Imaging 06/2014; 4(4):324-332. · 3.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This Opinion article discusses emerging evidence of direct contributions of nicotine to cancer onset and growth. The list of cancers reportedly connected to nicotine is expanding and presently includes small-cell and non-small-cell lung carcinomas, as well as head and neck, gastric, pancreatic, gallbladder, liver, colon, breast, cervical, urinary bladder and kidney cancers. The mutagenic and tumour-promoting activities of nicotine may result from its ability to damage the genome, disrupt cellular metabolic processes, and facilitate growth and spreading of transformed cells. The nicotinic acetylcholine receptors (nAChRs), which are activated by nicotine, can activate several signalling pathways that can have tumorigenic effects, and these receptors might be able to be targeted for cancer therapy or prevention. There is also growing evidence that the unique genetic makeup of an individual, such as polymorphisms in genes encoding nAChR subunits, might influence the susceptibility of that individual to the pathobiological effects of nicotine. The emerging knowledge about the carcinogenic mechanisms of nicotine action should be considered during the evaluation of regulations on nicotine product manufacturing, distribution and marketing.
Nature Reviews Cancer 05/2014; 14(6). DOI:10.1038/nrc3725 · 37.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A search for novel and more efficient therapeutic modalities of inflammatory bowel disease (IBD) is one of the most important tasks of contemporary medicine. The anti-inflammatory action of nicotine in IBD might be therapeutic, but its toxicity due to off-target and nonreceptor effects limited its use and prompted a search for nontoxic nicotinergic drugs. We tested the hypothesis that SLURP-1 and -2-the physiological nicotinergic substances produced by the human intestinal epithelial cells (IEC) and immunocytes-can mimic the anti-inflammatory effects of nicotine. We used human CCL-241 enterocytes, CCL-248 colonocytes, CCRF-CEM T-cells, and U937 macrophages. SLURP-1 diminished the TLR9-dependent secretion of IL-8 by CCL-241, and IFN γ -induced upregulation of ICAM-1 in both IEC types. rSLURP-2 inhibited IL-1 β -induced secretion of IL-6 and TLR4- and TLR9-dependent induction of CXCL10 and IL-8, respectively, in CCL-241. rSLURP-1 decreased production of TNF α by T-cells, downregulated IL-1 β and IL-6 secretion by macrophages, and moderately upregulated IL-10 production by both types of immunocytes. SLURP-2 downregulated TNF α and IFN γ R in T-cells and reduced IL-6 production by macrophages. Combining both SLURPs amplified their anti-inflammatory effects. Learning the pharmacology of SLURP-1 and -2 actions on enterocytes, colonocytes, T cells, and macrophages may help develop novel effective treatments of IBD.
BioMed Research International 05/2014; 2014:609086. DOI:10.1155/2014/609086 · 2.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Grover's disease (GD) is a transient or persistent, monomorphous, papulovesicular, asymptomatic or pruritic eruption classified as non-familial acantholytic disorder. Contribution of autoimmune mechanisms to GD pathogenesis remains controversial. The purpose of this study was to investigate antibody-mediated autoimmunity in 11 patients with GD, 4 of which were positive for IgA and/or IgG anti-keratinocyte antibodies by indirect immunofluorescence. We used the most sensitive proteomic technique for an unbiased analysis of IgA- and IgG-autoantibody reactivities. Multiplex analysis of autoantibody responses revealed autoreactivity of all 11 GD patients with cellular proteins involved in the signal transduction events regulating cell development, activation, growth, death, adhesion and motility. Semi-quantitative fluorescence analysis of cultured keratinocytes pretreated with sera from each patient demonstrated decreased intensity of staining for desmoglein 1 and/or 3 and PCNA, whereas 4 of 10 GD sera induced BAD expression, indicating that binding of autoantibodies to keratinocytes alters expression/function of their adhesion molecules and activates apoptosis. We also tested the ability of GD sera to induce visible alterations of keratinocyte shape and motility in vitro but found no specific changes. Thus, our results demonstated that humoral autoimmunity in GD can be mediated by both IgA and IgG autoantibodies. At this point, however, it is impossible to conclude whether these autoantibodies cause or are caused by the disease. Anti-desmoglein antibodies may be triggered by exposure to immune system of sequestered antigens due to disintegration of desmosomes during primary acantholysis. Clarifying etiology of GD will help improve treatment, which currently is symptomatic and of marginal effectiveness. This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Development of novel methods of early diagnosis of lung cancer is one of the major tasks of contemporary clinical and experimental oncology. In this study, we utilized the tobacco nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung cancer in A/J mice as an animal model for development of a new imaging technique for early diagnosis of lung cancer. Lung cancer cells in A/J mice overexpress nicotinic acetylcholine receptors. Longitudinal CT scans were carried out over a period of 8 months after NNK treatment, followed by PET/CT scans with 18F-Nifene that binds to α4-made nicotinic receptors with high affinity. PET/CT scans of lungs were also obtained ex vivo. CT revealed the presence of lung nodules in 8-month NNK-treated mice, while control mice had no tumors. Imaging of live animals prior to necropsy allowed correlation of results of tumor load via PET/CT and histopathological findings. Significant amount of 18F-Nifene was seen in the lungs of NNK-treated mice, whereas lungs of control mice showed only minor uptake of 18F-Nifene. Quantitative analysis of the extent and amount of 18F-Nifene binding in lung in vivo and ex vivo demonstrated a higher tumor/nontumor ratio due to selective labeling of tumor nodules expressing abundant α4 nicotinic receptor subunits. For comparison, we performed PET/CT studies with 18F-FDG, which is used for the imaging diagnosis of lung cancer. The tumor/nontumor ratios for 18F-FDG were lower than for 18F-Nifene. Thus, we have developed a novel diagnostic imaging approach to early diagnosis of lung cancer using 18F-Nifene PET/CT. This technique allows quantitative assessment of lung tumors in live mice, which is critical for establishing tumor size and location, and also has salient clinical implications.
[Show abstract][Hide abstract] ABSTRACT: The development of non-hormonal treatment of pemphigus vulgaris (PV) has been hampered by a lack of clear understanding of the mechanisms leading to keratinocyte (KC) detachment and death in pemphigus. In this study, we sought to identify changes in the vital mitochondrial functions in KCs treated with the sera from PV patients and healthy donors. PV sera significantly increased proton leakage from KCs, suggesting that PV IgGs increase production of reactive oxygen species (ROS). Indeed, measurement of intracellular ROS production showed a drastic increase of cell staining in response to treatment by PV sera, which was confirmed by FACS analysis. Exposure of KCs to PV sera also caused dramatic changes in the mitochondrial membrane potential detected with the JC-1 dye. These changes can trigger the mitochondria-mediated intrinsic apoptosis. While sera from different PV patients elicited unique patterns of mitochondrial damage, the mitochondria-protecting drugs nicotinamide, minocycline and cyclosporine A exhibited a uniform protective effect. Their therapeutic activity was validated in the passive transfer model of PV in neonatal BALB/c mice. The highest efficacy of mitochondrial protection of the combination of these drugs found in mitochondrial assay was consistent with the ability of the same drug combination to abolish acantholysis in mouse skin. These findings provide a theoretical background for clinical reports of the efficacy of mitochondria-protecting drugs in PV patients. Pharmacological protection of mitochondria and/or compensation of an altered mitochondrial function may therefore become a novel approach to development of personalized non-hormonal therapies of patients with this potentially lethal autoimmune blistering disease.