Cytokines as therapeutic drugs

The JAK-STAT pathway: from structural biology to cytokine engineering

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway serves as a paradigm for signal transduction from the extracellular environment to the nucleus. It plays a pivotal role in physiological functions, such as hematopoiesis, immune balance, tissue homeostasis, and surveillance against tumors. Dysregulation of this pathway may lead to various disease conditions such as immune deficiencies, autoimmune diseases, hematologic disorders, and cancer. Due to its critical role in maintaining human health and involvement in disease, extensive studies have been conducted on this pathway, ranging from basic research to medical applications. Advances in the structural biology of this pathway have enabled us to gain insights into how the signaling cascade operates at the molecular level, laying the groundwork for therapeutic development targeting this pathway. Various strategies have been developed to restore its normal function, with promising therapeutic potential. Enhanced comprehension of these molecular mechanisms, combined with advances in protein engineering methodologies, has allowed us to engineer cytokines with tailored properties for targeted therapeutic applications, thereby enhancing their efficiency and safety. In this review, we outline the structural basis that governs key nodes in this pathway, offering a comprehensive overview of the signal transduction process. Furthermore, we explore recent advances in cytokine engineering for therapeutic development in this pathway.

Innate Immune-Enhancing Effect of Pinus densiflora Pollen Extract via NF-κB Pathway Activation

Considering the emergence of various infectious diseases, including the coronavirus disease 2019 (COVID-19), people's attention has shifted towards immune health. Consequently, immune-enhancing functional foods have been increasingly consumed. Hence, developing new immune-enhancing functional food products is needed. Pinus densiflora pollen can be collected from the male red pine tree, which is commonly found in Korea. P. densiflora pollen extract (PDE), obtained by water extraction, contained polyphenols (216.29 ± 0.22 mg GAE/100 g) and flavonoids (35.14 ± 0.04 mg CE/100 g). PDE significantly increased the production of nitric oxide (NO) and reactive oxygen species (ROS) but, did not exhibit cytotoxicity in RAW 264.7 cells. Western blot results indicated that PDE induced the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2. PDE also significantly increased the mRNA and protein levels of cytokines and the phosphorylation of IKKα/β and p65, as well as the activation and degradation of IκBα. Additionally, western blot analysis of cytosolic and nuclear fractions and immunofluorescence assay confirmed that the translocation of p65 to the nucleus after PDE treatment. These results confirmed that PDE increases the production of cytokines, NO, and ROS by activating NF-κB. Therefore, PDE is a promising nutraceutical candidate for immune-enhancing functional foods.

Mass Spectrometry Approaches Empowering Neuropeptide Discovery and Therapeutics

The discovery of insulin in the early 1900s ushered in the era of research related to peptides acting as hormones and neuromodulators, among other regulatory roles. These essential gene products are found in all organisms, from the most primitive to the most evolved, and carry important biologic information that coordinates complex physiology and behavior; their misregulation has been implicated in a variety of diseases. The evolutionary origins of at least 30 neuropeptide signaling systems have been traced to the common ancestor of protostomes and deuterostomes. With the use of relevant animal models and modern technologies, we can gain mechanistic insight into orthologous and paralogous endogenous peptides and translate that knowledge into medically relevant insights and new treatments. Groundbreaking advances in medicine and basic science influence how signaling peptides are defined today. The precise mechanistic pathways for over 100 endogenous peptides in mammals are now known and have laid the foundation for multiple drug development pipelines. Peptide biologics have become valuable drugs due to their unique specificity and biologic activity, lack of toxic metabolites, and minimal undesirable interactions. This review outlines modern technologies that enable neuropeptide discovery and characterization, and highlights lessons from nature made possible by neuropeptide research in relevant animal models that is being adopted by the pharmaceutical industry. We conclude with a brief overview of approaches/strategies for effective development of peptides as drugs. SIGNIFICANCE STATEMENT: Neuropeptides, an important class of cell-cell signaling molecules, are involved in maintaining a range of physiological functions. Since the discovery of insulin's activity, over 100 bioactive peptides and peptide analogs have been used as therapeutics. Because these are complex molecules not easily predicted from a genome and their activity can change with subtle chemical modifications, mass spectrometry (MS) has significantly empowered peptide discovery and characterization. This review highlights contributions of MS-based research towards the development of therapeutic peptides.

Blocking only the bad side of IL-6 in inflammation and cancer

Interleukin-6 (IL-6) is considered an inflammatory cytokine, which is involved not only in most inflammatory states but it also plays a prominent role in inflammation associated cancers. The response of cells to the cytokine strictly depends on the presence of the IL-6 receptor (IL-6R),which presents IL-6 to the signal transducing receptor subunit gp130, which is expressed on all cells of the body. The expression of IL-6R is limited to some cells, which are therefore IL-6 target cells. The IL-6R can be cleaved by proteases and the thus generated soluble IL-6R (sIL-6R) still binds the ligand IL-6. The complex of IL-6 and sIL-6R can bind to gp130 on any cell, induce dimerization of gp130 and intracellular signaling. This process has been named IL-6 trans-signaling. A fusion protein of soluble gp130 with the constant portion of human IgG1 (sgp130Fc) turned out to be a potent and specific inhibitor of IL-6 trans-signaling. In many animal models of human diseases the significance of IL-6 trans-signaling has been analyzed. It turned out that the activities of IL-6 mediated by the sIL-6R are the pro-inflammatory activities of the cytokine whereas activities of IL-6 mediated by the membrane-bound IL-6R are rather protective and regenerative. The sgp130Fc protein has recently been developed into a biologic. The possible consequences of a specific IL-6 trans-signaling blockade is discussed in the light of the recent successfully concluded phase II clinical trials in patients with inflammatory bowel disease.

Interleukin-6: obstacles to targeting a complex cytokine in critical illness

Circulating concentrations of the pleiotropic cytokine interleukin-6 (IL-6) are known to be increased in pro-inflammatory critical care syndromes, such as sepsis and acute respiratory distress syndrome. Elevations in serum IL-6 concentrations in patients with severe COVID-19 have led to renewed interest in the cytokine as a therapeutic target. However, although the pro-inflammatory properties of IL-6 are widely known, the cytokine also has a series of important physiological and anti-inflammatory functions. An adequate understanding of the complex processes by which IL-6 signalling occurs is crucial for the correct interpretation of IL-6 concentrations in the blood or lung, the use of IL-6 as a critical care biomarker, or the design of effective anti-IL-6 strategies. Here, we outline the role of IL-6 in health and disease, explain the different types of IL-6 signalling and their contribution to the net biological effect of the cytokine, describe the approaches to IL-6 inhibition that are currently available, and discuss implications for the future use of treatments such as tocilizumab in the critical care setting.

Plasma Proteins As Biodosimetric Markers of Low-Dose Radiation in Mice

Long-term exposures to low-dose radiation (LDR) may trigger several specific biological responses, including dysregulation of the immune and inflammatory systems. Here, we examined whether biodosimetry of LDR can be used to protect tissues from radiation or assess cancer risk. Mice were subjected to gamma-irradiation with repeated or single-dose LDR, and then the organ indices, peripheral hemogram, and blood biochemistry were analyzed. An antibody array was applied followed by enzyme-linked immunosorbent assay to evaluate the utility of multiple plasma proteins as biomarkers of repeated LDR in a murine model. LDR induced inapparent symptoms but slight variations in peripheral blood cell counts and alterations in blood biochemical indicator levels. Specific plasma proteins in the LDR groups were altered in response to a higher dose of irradiation at the same time points or a single-dose equivalent to the same total dose. Plasma levels of interleukin (IL)-5, IL-12p40, P-selectin, and serum amyloid A1 were associated with the LDR dose and thus may be useful as dosimetric predictors of LDR in mice. Estimating the levels of certain plasma proteins may yield promising biodosimetry parameters to accurately identify individuals exposed to LDR, facilitating risk assessment of long-term LDR exposure in individuals.

Plasma Proteins as Biomarkers of Mortality After Total Body Irradiation in Mice

During large-scale acute radiation exposure, rapidly distinguishing exposed individuals from nonexposed individuals is necessary. Identifying those exposed to high and potentially lethal radiation doses, and in need of immediate treatment, is especially important. To address this and find plasma biomarkers to assess ionizing radiation-induced mortality in the early stages, mice were administered a whole-body lethal dose of γ radiation, and radiation-induced damage was evaluated. Multiple blood biomarkers were screened using an antibody array, followed by validation using enzyme-linked immunoassay. The results revealed that irradiation (IR)-induced mortality in mice and caused body weight and blood platelet losses in deceased mice compared to surviving mice. The levels of certain proteins differed after IR between these 2 groups. Specific proteins in preirradiated mice were also found to potentiate radiosensitivity. Plasma levels of interleukin (IL)-22, urokinase, resistin, and IL-6 were associated with radiation-induced mortality in irradiated mice and may be useful as potential mortality predictors. Our results suggest that estimating the levels of certain plasma proteins is a promising alternative to conventional cytogenetic biodosimetry to accurately identify individuals exposed to high radiation doses and those at risk of death due to exposure. This strategy would facilitate the rapid triage of individuals requiring immediate and intensive medical treatment.

Theacrine alleviates chronic inflammation by enhancing TGF-β-mediated shifts via TGF-β/SMAD pathway in Freund's incomplete adjuvant-induced rats

Rheumatoid arthritis is a chronic and systemic autoimmune disease, which affects approximately 1% of the adult population worldwide. The present study investigated the therapeutic effect of theacrine (TC) on arthritis and its mechanisms in Freund's incomplete adjuvant (FIA)-induced SD rats. Rats were randomly divided into 5 groups: i) healthy control; ii) model; iii) positive control with methotrexate (MTX); iv) treatment with 12.5 mg/kg TC; and v) treatment with 25.0 mg/kg TC. The apparent scores, including changes in body weights, degree of paw swelling and arthritis indicators, were analyzed to evaluate the anti-chronic inflammatory effect of TC. The levels of interleukin (IL)-6 and transforming growth factor-β (TGF-β) in serum were measured by enzyme-linked immunosorbent assay. The protein and RNA expression levels of the critical factors in rats were measured to elucidate the mechanisms responsible for chronic inflammation and to verify molecular indexes of chronic inflammatory conditions. TC notably suppressed the severity of FIA-induced rat by attenuating the apparent scores, animal weight and inflammatory indexes in the 25 mg/kg TC group compared with the FIA rat model. Furthermore, TC significantly decreased the levels of IL-6 and increased the levels of TGF-β. Histopathological examinations indicated that TC rescued the synovial hyperplasia and inflammatory cell infiltration in joint tissues. In addition, TC enhanced TGF-β-mediated shifts in inflammatory marker expression in joint tissue. Overall, the present study demonstrated that TC exerted a superior anti-arthritic effect via the suppression of IL-6 and the activation of TGF-β by the TGF-β/SMAD pathway.

Cancer Immunotherapies and Humanized Mouse Drug Testing Platforms

Cancer immunotherapy is a type of treatment that restores and stimulates human immune system to inhibit cancer growth or eradicate cancer. It serves as one of the latest systemic therapies, which has been approved to treat different types of cancer in patients. Nevertheless, the clinical response rate is unsatisfactory and the response observed is mostly a partial response in patients. Despite the continuous improvement and identification of novel cancer immunotherapy, there is a pressing need to establish a robust platform to evaluate the efficacy and safety of pre-clinical drugs, simulate the interaction between patients’ tumor and immune system, and predict patients’ responses to the treatment. In this review, we summarize the pros and cons of existing immuno-oncology assay platforms, especially the humanized mouse models for the screening of cancer immunotherapy drugs. In addition, various emerging trends and progress of utilizing humanized mouse models as the screening tool are discussed. Of note, humanized mouse models can also be used for further development of personalized precision medicines to treat cancer. Collectively, these highlight the significance of humanized mouse models as the important platform for the screening of next generation cancer immunotherapy in vivo.

In Vitro Immune-Enhancing Activity of Ovotransferrin from Egg White via MAPK Signaling Pathways in RAW 264.7 Macrophages

Ovotransferrin (OTF) is a well-known protein of the transferrin family with strong iron chelating activity, resulting in its antimicrobial activity. Furthermore, OTF is known to have antioxidant, anticancer, and antihypertensive activities. However, there have been few studies about the immune-enhancing activity of OTF. In current study, we investigated the immune-enhancing activity of OTF using the murine macrophage cells in vitro. The effect of OTF on production of pro-inflammatory mediators and cytokines were determined using Griess assay and quantitative real-time PCR. Using Neutral Red uptake assay, we confirmed the effect of OTF on phagocytic activity of macrophages. Ovotransferrin significantly increased the production of nitric oxide (NO) and secretion of inducible nitric oxide synthase (iNOS) mRNA with no cytotoxic activity. Ovotransferrin (2 mg/mL) stimulated NO production up to 31.9±3.5 μM. Ovotransferrin significantly increased the mRNA expression levels of pro-inflammatory cytokines which are tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), and IL-6: OTF (2 mg/mL) treatment increased the secretion of mRNA for TNF-α, IL-1β, and IL-6 by 22.20-, 37.91-, and 6.17-fold of the negative control, respectively. The phagocytic activity of macrophages was also increased by OTF treatment significantly compared with negative control. Also, OTF treatment increased phosphorylation level of MAPK signaling pathways. These results indicated that OTF has immune-enhancing activity by activating RAW 264.7 macrophages via MAPK pathways.

In silico mutational analysis and identification of stability centers in human interleukin-4

Interleukin-4 (IL-4) is a multifunctional cytokine that plays a critical role in apoptosis, differentiation and proliferation. The intensity of IL4 response depends upon binding to its receptor, IL-4R. The therapeutic efficiency of interleukins can be increased by generating structural mutants having greater stability. In the present work, attempts were made to increase the stability of human IL-4 using in-silico site directed mutagenesis. Different orthologous sequences of IL4 from Pan troglodytes, Aotusnigriceps, Macacamulatta, Papiohamadryas, Chlorocebusaethiops, Vicugnapacos, Susscrofa and Homo sapiens were aligned using Clustal Omega that revealed the conserved and non-conserved positions. For each non-conserved position, possible favorable and stabilizing mutations were found using CUPSAT with predicted ΔΔG (kcal/mol). The one with highest ΔΔG (kcal/mol) among all possible mutations, for each non-conserved position was selected and introduced manually in human IL-4 sequence resulting in multiple mutants of IL-4. Mutant proteins were modeled using structure of IL4 (PDB ID: 2B8U) as a template by SWISS MODEL. The mutants A49L and Q106T were identified to have stability centre using SCide. Molecular dynamics and docking analysis also confirmed the mutants stability and binding respectively. Mutants A49L and Q106T had -7.580079 kcal/mol and -39.418124 kcal/mol respectively lesser energy value than the wild type IL4. The result suggested that, the stability of human IL-4 has been increased by mutation.

Interleukin-6: designing specific therapeutics for a complex cytokine

Interleukin-6 (IL-6) is a pivotal cytokine with a diverse repertoire of physiological functions that include regulation of immune cell proliferation and differentiation. Dysregulation of IL-6 signalling is associated with inflammatory and lymphoproliferative disorders such as rheumatoid arthritis and Castleman disease, and several classes of therapeutics have been developed that target components of the IL-6 signalling pathway. So far, monoclonal antibodies against IL-6 or IL-6 receptor (IL-6R) and Janus kinases (JAK) inhibitors have been successfully developed for the treatment of autoimmune diseases such as rheumatoid arthritis. However, clinical trials of agents targeting IL-6 signalling have also raised questions about the diseases and patient populations for which such agents have an appropriate benefit-risk profile. Knowledge from clinical trials and advances in our understanding of the complexities of IL-6 signalling, including the potential to target an IL-6 trans-signalling pathway, are now indicating novel opportunities for therapeutic intervention. In this Review, we overview the roles of IL-6 in health and disease and analyse progress with several approaches of inhibiting IL-6-signalling, with the aim of illuminating when and how to apply IL-6 blockade.

Altered Cytokine Expression and Barrier Properties after In Vitro Infection of Porcine Epithelial Cells with Enterotoxigenic Escherichia coli and Probiotic Enterococcus faecium

The aim of the present study was to elucidate the effects of the probiotic feed additive Enterococcus faecium NCIMB 10415 (E. faecium) on porcine jejunal epithelial cells (IPEC-J2) during an in vitro challenge with enterotoxigenic Escherichia coli (ETEC). Cells were incubated with E. faecium, ETEC, or both, and the effects on barrier function and structure and intra- and intercellular signaling were determined. Coincubation with E. faecium abolished the ETEC-induced decrease in transepithelial resistance (R_t) (p ≤ 0.05). No differences were seen in the expression levels of the intercellular connecting tight junction proteins examined. However, for the first time, a reorganization of the monolayer was observed in ETEC-infected cells but not in coincubated cells. ETEC induced an increase in cytotoxicity that was prevented by coincubation (p ≤ 0.05), whereas apoptosis rates were not affected by bacterial treatment. ETEC increased the mRNA expression and release of proinflammatory cytokines TNF-α, IL-1α, and IL-6 which could be prevented by coincubation for TNF-α mRNA expression and IL-6 protein (p ≤ 0.05). Likewise, cAMP concentrations elevated by ETEC were reduced in coincubated cells (p ≤ 0.05). These findings indicate a protective effect of the probiotic E. faecium on inflammatory responses during infection with ETEC.

Potential role of herbal remedies in stem cell therapy: proliferation and differentiation of human mesenchymal stromal cells

Stem cell therapy has revolutionized modern clinical therapy with the potential of stem cells to differentiate into many different cell types which may help to replace different cell lines of an organism. Innumerous trials are carried out to merge new scientific knowledge and techniques with traditional herbal extracts that may result in less toxic, affordable, and highly available natural alternative therapeutics. Currently, mesenchyamal stromal cell (MSC) lines are treated with individual and mixtures of crude herbal extracts, as well as with purified compounds from herbal extracts, to investigate the mechanisms and effects of these on stem cell growth and differentiation. Human MSCs (hMSCs) possess multilineage, i.e., osteogenic, neurogenic, adipogenic, chondrogenic, and myogenic, differentiation abilities. The proliferative and differentiation properties of hMSCs treated with herbal extracts have shown promise in diseases such as osteoporosis, neurodegenerative disorders, and other tissue degenerative disorders. Well characterized herbal extracts that result in increased rates of tissue regeneration may be used in both stem cell therapy and tissue engineering for replacement therapy, where the use of scaffolds and vesicles with enhanced attaching and proliferative properties could be highly advantageous in the latter. Although the clinical application of herbal extracts is still in progress due to the variability and complexity of bioactive constituents, standardized herbal preparations will strengthen their application in the clinical context. We have critically reviewed the proliferative and differentiation effects of individual herbal extracts on hMSCs mainly derived from bone marrow and elaborated on the plausible underlying mechanisms of action. To be fruitfully used in reparative and regenerative therapy, future directions in this area of study should (i) make use of hMSCs derived from different non-traditional sources, including medical waste material (umbilical cord, Wharton's jelly, and placenta), (ii) take account of the vast numbers of herbal extracts used in traditional medicine globally, and (iii) investigate the mechanisms and pathways of their effects on hMSCs.

Radioprotective effects of dragon's blood and its extracts on radiation-induced myelosuppressive mice

ETHNOPHARMACOLOGICAL RELEVANCE

Dragon׳s blood, a traditional Chinese herb, has been used to "panacea of blood activating" and its major biological activity appears to be from phenolic compounds. In this study, our research aims to examine the effects of Dragon׳s blood (DB) and its extracts (DBE) on radiation-induced myelosuppressive mice.

MATERIALS AND METHODS

Adult BALB/C mice were exposed to the whole body irradiation with 4 Gy (60)Co γ-rays. DB and DBE were respectively administered orally for 5 constitutive days prior to irradiation treatment. The radioprotective effects and relevant mechanisms of DB and DBE in radiation-induced bone marrow injury were investigated by ex vivo examination.

RESULTS

We found that the administration of DB and DBE significantly increased the numbers of peripheral blood cells and colony forming unit of bone marrow-derived stem/progenitor cells. Interestingly, compared with the irradiation group, the administration of DB and DBE significantly decreased the levels of the inflammatory cytokines such as IL-6, TNF-α and IFN-γ and oxidative stress injury such as SOD, CAT, GSH, MDA in serum of mice. Furthermore, DBE markedly improved the morphology of bone marrow histopathology.

CONCLUSIONS

Our data suggest that DB and DBE effectively attenuate radiation-induced damage in bone marrow, which is likely associated with the anti-oxidative and anti-inflammatory properties of DB and DBE.

Alpha-tocopherol succinate- and AMD3100-mobilized progenitors mitigate radiation combined injury in mice

The purpose of this study was to elucidate the role of alpha-tocopherol succinate (TS)- and AMD3100-mobilized progenitors in mitigating combined injury associated with acute radiation exposure in combination with secondary physical wounding. CD2F1 mice were exposed to high doses of cobalt-60 gamma-radiation and then transfused intravenously with 5 million peripheral blood mononuclear cells (PBMCs) from TS- and AMD3100-injected mice after irradiation. Within 1 h after irradiation, mice were exposed to secondary wounding. Mice were observed for 30 d after irradiation and cytokine analysis was conducted by multiplex Luminex assay at various time-points after irradiation and wounding. Our results initially demonstrated that transfusion of TS-mobilized progenitors from normal mice enhanced survival of acutely irradiated mice exposed 24 h prior to transfusion to supralethal doses (11.5-12.5 Gy) of (60)Co gamma-radiation. Subsequently, comparable transfusions of TS-mobilized progenitors were shown to significantly mitigate severe combined injuries in acutely irradiated mice. TS administered 24 h before irradiation was able to protect mice against combined injury as well. Cytokine results demonstrated that wounding modulates irradiation-induced cytokines. This study further supports the conclusion that the infusion of TS-mobilized progenitor-containing PBMCs acts as a bridging therapy in radiation-combined-injury mice. We suggest that this novel bridging therapeutic approach involving the infusion of TS-mobilized hematopoietic progenitors following acute radiation exposure or combined injury might be applicable to humans.

Preconditioning thermal therapy: flipping the switch on IL-6 for anti-tumour immunity

Cancer immunotherapy aims to generate long-lived, tumour-specific adaptive immunity to limit dysregulated tumour progression and metastasis. Tumour vasculature has emerged as a critical checkpoint controlling the efficacy of immunotherapy since it is the main access point for cytotoxic T cells to reach tumour cell targets. Therapeutic success has been particularly challenging to achieve because of the local, cytokine-rich inflammatory milieu that drives a pro-tumourigenic programme supporting the growth and survival of malignant cells. Here, we focus on recent evidence that systemic thermal therapy can switch the activities of the inflammatory cytokine, interleukin-6 (IL-6), to a predominantly anti-tumourigenic function that promotes anti-tumour immunity by mobilising T cell trafficking in the recalcitrant tumour microenvironment.

Cordyceps sinensis health supplement enhances recovery from taxol-induced leukopenia

This study aimed to evaluate the ability of the health food supplement Cordyceps sinensis (CS) to ameliorate suppressive effects of chemotherapy on bone marrow function as a model for cancer treatment. Mice were treated with Taxol (17 mg/kg body wt) one day before oral administration of a hot-water extract of CS (50 mg/kg daily) that was given daily for 3 weeks. White blood cell counts in peripheral blood of mice receiving Taxol were at 50% of normal levels on day 28 but had recovered completely in mice treated with CS. In vitro assays showed that CS enhanced the colony-forming ability of both granulocyte macrophage colony forming unit (GM-CFU) and osteogenic cells from bone marrow preparations and promoted the differentiation of bone marrow mesenchymal stromal cells into adipocytes, alkaline phosphatase-positive osteoblasts, and bone tissue. This result could be attributed to enhanced expression of Cbfa1 (core binding factor a) and BMP-2 (bone morphogenetic protein) with concurrent suppression of ODF (osteoclast differentiation factor/RANK [receptor activator of NF-kappaB]) ligand. In summary, CS enhances recovery of mice from leukopenia caused by Taxol treatment. It appears to do so by protecting both hematopoietic progenitor cells directly and the bone marrow stem cell niche through its effects on osteoblast differentiation.

Radiation-induced alterations in cytokine production by skin cells

Ionizing radiation exposure of skin results in a cutaneous radiation reaction comprising all pathophysiological reactions and clinical symptoms in irradiated skin. Biological responses of skin occur in a characteristic temporal pattern and mainly depend on radiation quality, dose rate, total dose, and cellular conditions. Immediately after irradiation, production of cytokines by skin cells is initiated and continues as a cascade during all stages of the cutaneous radiation syndrome leading to progressive late symptoms, the predominant of which is fibrosis. Cytokines are important signaling molecules mediating communicative interactions both locally between different cell types within dermal tissues and distantly between organs. Although during recent years much progress has been made in dissecting the complex cytokine network, the role of cytokines in the pathophysiology of the cutaneous radiation reaction is only beginning to be elucidated. Previous studies indicate that the major cytokines in the response of skin cells to ionizing radiation include IL (interleukin)-1, IL-6, tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta, and the chemokines IL-8 and eotaxin. In this paper, existing data on the radiation-induced modulation of cytokine expression by skin cells are reviewed.

Protection against radiation-induced bone marrow and intestinal injuries by Cordyceps sinensis, a Chinese herbal medicine

Bone marrow and intestinal damage limits the efficacy of radiotherapy for cancer and can result in death if the whole body is exposed to too high a dose, as might be the case in a nuclear accident or terrorist incident. Identification of an effective nontoxic biological radioprotector is therefore a matter of some urgency. In this study, we show that an orally administered hot-water extract from a Chinese herbal medicine, Cordyceps sinensis (CS), protects mice from bone marrow and intestinal injuries after total-body irradiation (TBI). CS increased the median time to death from 13 to 20 days after 8 Gy TBI and from 9 to 18 days after 10 Gy TBI. Although CS-treated mice receiving 10 Gy TBI survived intestinal injury, most died from bone marrow failure, as shown by severe marrow hypoplasia in mice dying between 18 and 24 days. At lower TBI doses of 5.5 and 6.5 Gy, CS protected against bone marrow death, an effect that was confirmed by the finding that white blood cell counts recovered more rapidly. In vitro, CS reduced the levels of free radical species (ROS) within cells, and this is one likely mechanism for the radioprotective effects of CS, although probably not the only one.

Influence of in vitro and in vivo insulin treatment on the hormone (histamine, serotonin, endorphin and triiodothyronine) content of thymus and spleen cells

Thymic and spleen cells were treated in vitro or in vivo with insulin. The in vitro treatments were done with 10(-6), 10(-9), 10(-12) and 10(-15) M concentrations for 30 min and after that histamine, serotonin, endorphin and triiodothyronine (T3) content of the cells were detected by using antibodies to the hormones and flow cytometry as well as confocal microscopy. For in vivo treatment 1 IU/kg insulin was given for adult rats and 1 h after that the target hormone contents were determined by the same manner. Histamine and T3 content radically decreased in the thymus after in vitro treatment independent on the insulin concentrations administered. In vivo treatment halved histamine and T3 content. Serotonin content also decreased after in vitro treatment with the two higher concentrations, however the in vivo treatment did not cause a change. Histamine content was elevated after in vitro treatment in the spleen, independent on the insulin concentration. Endorphin level was not influenced at all. The experiments demonstrate that insulin is a factor which regulates the content (production, storage, secretion?) of some immunologically important molecules of the immune cells. Since each hormone molecule studied has important immunomodulatory role, the experiment points to the indirect immunomodulatory role of insulin.

Hormones in the nucleus. Immunologically demonstrable biogenic amines (serotonin, histamine) in the nucleus of rat peritoneal mast cells

Using 1-ethyl-3(3-dimethyl-aminopropyl)-carbodiimide (EDAC) fixation and immunocytochemical confocal microscopic study, bright serotonin and histamine fluorescence appeared in the nucleus of rat peritoneal mast cells. In case of paraformaldehyde fixation, this was not observed. The phenomenon can be explained by the cross-linking effect of EDAC, which did not allow the efflux of biogenic amines from the nucleus. This means that biogenic amines are present in the nucleus of mast cells, and this is supported by the flow cytometric measurement data of the whole cell. Other hormones studied (triiodothyronine, insulin, and endorphin) were not present in the nucleus. Four pharmaca with biogenic amine-influencing character in the central nervous system were used for studying the relation between the external (surrounding and cytoplasmic) and nuclear biogenic amine content of mast cells. Fluoxetine, a serotonin reuptake inhibitor depleted nuclear as well as cytoplasmic serotonin content. Clorgyline, a MAO-A inhibitor, decreased cytoplasmic serotonin content and weakened nuclear serotonin fluorescence. The tryptophan hydroxylase inhibitor, para-chlorophenylalanine (PCPA), and the mast cell degranulator, Compound 48/80, reduced cytoplasmic serotonin content without influencing nuclear content. Histamine fluorescence was influenced solely by fluoxetine. The results show that nuclear 5-HT content is dependent firstly of serotonin uptake and reuptake. To our knowledge, this is the first exact report on the presence of non-steroid-type-receptor-transported hormones inside the nucleus of a cell.

Role of cytokines and growth factors in radioprotection

Cytokines and growth factors are growing groups of proteins that are responsible for the communication between cells of the immune system, hematopoietic cells, and other cell types. The cloning and large-scale production in a recombinant form of these agents in pharmacological quantities permitted investigations aimed at assessing the benefit they may provide in preserving and restoring functions of tissues compromised by irradiation. We have extensively examined past investigations which suggest that some cytokines and growth factors protect animals from radiation lethality when given prior to or after irradiation, and even in untreated animals, these cytokines serve in innate defenses against external stimuli. In contrast, some cytokines given before irradiation sensitize the animals to radiation lethality. Unfortunately, due to their adverse side effects, these cytokines were not found suitable as radioprotectors. Recent studies suggest that new approaches may bring cytokines and growth factors in clinic for radiation injury. The information and insight gained about therapeutic potential of cytokine manipulation will allow for more rational design of treatment protocols.

Immunobiological Characterization of N-Nitrosomethylurea-Induced Rat Breast Carcinomas: Tumoral IL-10 Expression as a Possible Immune Escape Mechanism

Improvement of immunotherapy-based protocols in cancer requires a better understanding of tumor microenvironment and tumor-host interaction. Stromal and immune cells and molecules such as cytokines, chemokines, growth factors and metalloproteases mediate tumor-host interaction determining, at least in part, tumor development. In the present study, we used an immunohistochemical approach to explore leukocyte sub-populations, cytokine profiles and costimulatory molecule expression in rat N -Nitrosomethylurea (NMU)-induced breast tumors. Our results show a strong leukocyte infiltration mainly composed of macrophages and TCR alphabeta positive T cells. We observed a weak expression of costimulatory molecules (CD80, CD86) and an absence of inflammatory cytokines (IFNgamma, TNFalpha, IP-10) and lymphocyte activation markers (CD25). Interestingly, this immunosuppressed status could be a consequence of IL-10 expression by malignant cells, as demonstrated by immunohistology and western blot analysis, which seems to be an early event during mammary carcinogenesis. Analysis of a cell line derived from an NMU-induced rat breast tumor showed that this cell line also expresses IL-10. This study shows that the NMU model of rat breast cancer could be used to evaluate different immune based therapies as well as to study the role of IL-10 in breast cancer. Furthermore, this rat breast cancer model shows an immunohistological profile similar to that found in human cancer and the fact that it develops like spontaneously arising malignancies make it interesting as a cancer model in immunobiology.

Peroxisome proliferator-activated receptor-gamma is deficient in alveolar macrophages from patients with alveolar proteinosis

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is a ligand-activated, nuclear transcription factor that regulates genes involved in lipid and glucose metabolism, inflammation, and other pathways. The hematopoietic growth factor, granulocyte macrophage colony-stimulating factor (GM-CSF), is essential for lung homeostasis and is thought to regulate surfactant clearance, but mechanisms involved are unknown. GM-CSF is reported to stimulate PPAR-gamma, but the activation status of PPAR-gamma in human alveolar macrophages has not been defined. In pulmonary alveolar proteinosis (PAP), a rare interstitial lung disease, surfactant accumulates in alveolar airspaces, resident macrophages become engorged with lipoproteinaceous material, and GM-CSF deficiency is strongly implicated in pathogenesis. Here we show that PPAR-gamma mRNA and protein are highly expressed in alveolar macrophages of healthy control subjects but severely deficient in PAP in a cell-specific manner. Further, we show that the PPAR-gamma-regulated lipid scavenger receptor, CD36, is also deficient in PAP. PPAR-gamma and CD36 deficiency are not intrinsic to PAP alveolar macrophages, but can be upregulated by GM-CSF therapy. Moreover, GM-CSF treatment of patients with PAP fully restores PPAR-gamma to healthy control levels. Based upon these novel findings, we hypothesize that GM-CSF regulates lung homeostasis via PPAR-gamma-dependent pathways.

The secreted protein discovery initiative (SPDI), a large-scale effort to identify novel human secreted and transmembrane proteins: a bioinformatics assessment

A large-scale effort, termed the Secreted Protein Discovery Initiative (SPDI), was undertaken to identify novel secreted and transmembrane proteins. In the first of several approaches, a biological signal sequence trap in yeast cells was utilized to identify cDNA clones encoding putative secreted proteins. A second strategy utilized various algorithms that recognize features such as the hydrophobic properties of signal sequences to identify putative proteins encoded by expressed sequence tags (ESTs) from human cDNA libraries. A third approach surveyed ESTs for protein sequence similarity to a set of known receptors and their ligands with the BLAST algorithm. Finally, both signal-sequence prediction algorithms and BLAST were used to identify single exons of potential genes from within human genomic sequence. The isolation of full-length cDNA clones for each of these candidate genes resulted in the identification of >1000 novel proteins. A total of 256 of these cDNAs are still novel, including variants and novel genes, per the most recent GenBank release version. The success of this large-scale effort was assessed by a bioinformatics analysis of the proteins through predictions of protein domains, subcellular localizations, and possible functional roles. The SPDI collection should facilitate efforts to better understand intercellular communication, may lead to new understandings of human diseases, and provides potential opportunities for the development of therapeutics.

Effects of the nerve growth factor on the survival and wound healing in mice with combined radiation and wound injury

High dose of ionizing radiation could cause bone-marrow aplasia and delay wound healing. Nerve growth factor (NGF) has been demonstrated to play roles in wound healing and to affect the functional activities of mature immune and hematopoietic cells. In this study, we investigated the effects of NGF on survival and wound healing in mice with combined radiation and wound injury. Immunohistochemical analysis indicated that the expression of NGF decreased significantly at postwounding days 3, 5, 7, 10 and 14 in wounded tissues combined with total body irradiation of 5 Gy. NGF significantly increased the survival and migration of skin fibroblasts with the irradiation of 15 Gy in in vitro experiments. Intraperitoneal and topical applications of NGF increased the survival rate, peripheral white blood cells and bone-marrow nucleated cells; they also promoted wound healing and increased the cell number of fibroblasts and blood capillaries in granulation tissues. These results showed evidence that NGF could increase wound healing and promote survival in irradiated animals. This dual effect of NGF may provide a new tool for the treatment of radiation-combined injuries.