Granzymes: a family of lymphocyte granule serine proteases

Development of effective tumor immunotherapy using a novel dendritic cell-targeting Toll-like receptor ligand

Although dendritic cell (DC)-based immunotherapy shows little toxicity, improvements should be necessary to obtain satisfactory clinical outcome. Using interferon-gamma injection along with DCs, we previously obtained significant clinical responses against small or early stage malignant tumors in dogs. However, improvement was necessary to be effective to largely developed or metastatic tumors. To obtain effective methods applicable to those tumors, we herein used a DC-targeting Toll-like receptor ligand, h11c, and examined the therapeutic effects in murine subcutaneous and visceral tumor models and also in the clinical treatment of canine cancers. In murine experiments, most and significant inhibition of tumor growth and extended survival was observed in the group treated with the combination of h11c-activated DCs in combination with interferon-gamma and a cyclooxygenase2 inhibitor. Both monocytic and granulocytic myeloid-derived suppressor cells were significantly reduced by the combined treatment. Following the successful results in mice, the combined treatment was examined against canine cancers, which spontaneously generated like as those in human. The combined treatment elicited significant clinical responses against a nonepithelial malignant tumor and a malignant fibrous histiocytoma. The treatment was also successful against a bone-metastasis of squamous cell carcinoma. In the successful cases, the marked increase of tumor-responding T cells and decrease of myeloid-derived suppressor cells and regulatory T cells was observed in their peripheral blood. Although the combined treatment permitted the growth of lung cancer of renal carcinoma-metastasis, the marked elevated and long-term maintaining of the tumor-responding T cells was observed in the patient dog. Overall, the combined treatment gave rise to emphatic amelioration in DC-based cancer therapy.

Cytotoxic activity in cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is a chronic disease caused by species of the protozoan Leishmania and characterised by the presence of ulcerated skin lesions. Both parasite and host factors affect the clinical presentation of the disease. The development of skin ulcers in CL is associated with an inflammatory response mediated by cells that control parasite growth but also contribute to pathogenesis. CD8+ T cells contribute to deleterious inflammatory responses in patients with CL through cytotoxic mechanisms. In addition, natural killer cells also limit Leishmania infections by production of interferon-γ and cytotoxicity. In this review, we focus on studies of cytotoxicity in CL and its contribution to the pathogenesis of this disease.

Modularly Constructed Synthetic Granzyme B Molecule Enables Interrogation of Intracellular Proteases for Targeted Cytotoxicity

Targeted therapies promise to increase the safety and efficacy of treatments against diseases ranging from cancer to viral infections. However, the vast majority of targeted therapeutics relies on the recognition of extracellular biomarkers, which are rarely restricted to diseased cells and are thus prone to severe and sometimes-fatal off-target toxicities. In contrast, intracellular antigens present a diverse yet underutilized repertoire of disease markers. Here, we report a protein-based therapeutic platform-termed Cytoplasmic Oncoprotein VErifier and Response Trigger (COVERT)-which enables the interrogation of intracellular proteases to trigger targeted cytotoxicity. COVERT molecules consist of the cytotoxic protein granzyme B (GrB) fused to an inhibitory N-terminal peptide, which can be removed by researcher-specified proteases to activate GrB function. We demonstrate that fusion of a small ubiquitin-like modifier 1 (SUMO1) protein to GrB yields a SUMO-GrB molecule that is specifically activated by the cancer-associated sentrin-specific protease 1 (SENP1). SUMO-GrB selectively triggers apoptotic phenotypes in HEK293T cells that overexpress SENP1, and it is highly sensitive to different SENP1 levels across cell lines. We further demonstrate the rational design of additional COVERT molecules responsive to enterokinase (EK) and tobacco etch virus protease (TEVp), highlighting the COVERT platform's modularity and adaptability to diverse protease targets. As an initial step toward engineering COVERT-T cells for adoptive T-cell therapy, we verified that primary human T cells can express, package, traffic, and deliver engineered GrB molecules in response to antigen stimulation. Our findings set the foundation for future intracellular-antigen-responsive therapeutics that can complement surface-targeted therapies.

QPY/RAH haplotypes of the GZMB gene are associated with natural killer cell cytotoxicity

Granzyme B (GzmB) is a component of cytolytic granules within NK cells and is involved in several pathologies. It has previously been reported that there are three non-synonymous coding SNPs (rs8192917; Q48R, rs11539752; P88A, and rs2236338; Y245H) in the GZMB gene and that the QPY/RAH allele was clustered together close to the C-terminal α-helix. However, it is unknown whether the function of GzmB produced from NK cells is influenced by QPY/RAH polymorphism. The authors investigated the distribution of QPY/RAH polymorphism of the GZMB gene in a Japanese population (n = 106), and the involvement of Q48R polymorphism in NK cell cytotoxicity, degranulation, and production of GzmB. A strong linkage disequilibrium was observed among these SNPs, and NK cell cytotoxicity was influenced by rs8192917 (Q48R). Moreover, it found that R⁴⁸-GzmB is a stable protein that accumulates to similar levels in activated NK cells as Q⁴⁸-GzmB. rs8192917 polymorphism may influence antitumor activity and the effect of antitumor cellular immunotherapy. The authors expect that these new informations about QPY/RAH polymorphism of the GZMB gene could help to assess the impact of NK cell cytotoxicity in several pathologies and aid their treatment.

Relationships among plasma granzyme B level, pruritus and dermatitis in patients with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a multifactorial inflammatory skin disease characterized by skin barrier dysfunction, allergic inflammation and intractable pruritus resistant to conventional antipruritic treatments, including H₁-antihistamines. Granzymes (Gzms) are a family of serine proteases expressed by cytotoxic T lymphocytes and natural killer cells that have been shown to modulate inflammation. However, the relationship between Gzms and pathology in AD remains unclear.

OBJECTIVE

This study assessed the correlation between plasma GzmB levels and severity of pruritus and dermatitis, in AD patients.

METHODS

Plasma was collected from 46 patients with AD, 24 patients with psoriasis, and 30 healthy controls. AD severity was assessed with the scoring atopic dermatitis (SCORAD) index, psoriasis severity with the psoriasis area and severity index (PASI), and degree of pruritus by visual analogue scale (VAS) score. GzmA, GzmB and gastrin releasing peptide (GRP) levels were measured by enzyme-linked immunosorbent assays.

RESULTS

Plasma GzmB concentrations were significantly higher in patients with AD and psoriasis than in healthy controls. Correlation analyses showed that plasma GzmB concentrations positively correlated with SCORAD and serum levels of severity markers such as thymus and activation-regulated chemokine, and lactate dehydrogenase in AD patients. Moreover, plasma levels of GRP, an itch-related peptide, were higher in patients with AD, positively correlating with VAS score and plasma GzmB level. In addition, plasma GzmB concentration was significantly lower in the treatment group than the untreated group with AD. Meanwhile, there were no correlations among GzmB levels, VAS score and PASI score in patients with psoriasis. In contrast to the results of plasma GzmB, plasma GzmA levels were unchanged among AD, psoriasis and healthy groups, and showed no correlations with VAS score and SCORAD index in patients with AD.

CONCLUSION

Plasma GzmB levels may reflect the degree of pruritus and dermatitis in patients with AD.

Purification and characterization of a fish granzymeA involved in cell-mediated immunity

Granzymes are serine proteases involved in the induction of cell death against non-self cells. The enzymes differ in their primary substrate specificity and have one of four hydrolysis activities: tryptase, Asp-ase, Met-ase and chymase. Although granzyme genes have been isolated from several fishes, evidence for their involvement in cytotoxicity has not yet been reported. In the present study, we attempted to purify and characterize a fish granzyme involved in cytotoxicity using ginbuna crucian carp. The cytotoxicity of leukocytes was significantly inhibited by the serine protease inhibitor ''3, 4-dichloroisocoumarin''. In addition, we found that granzymeA-like activity (hydrolysis of Z-GPR-MCA) was inhibited by the same inhibitor and significantly enhanced by allo-antigen stimulation in vivo. Proteins from leukocyte extracts were subjected to two steps of chromatographic purification using benzamidine-Sepharose and SP-Sepharose. The molecular weight of the purified enzyme was estimated to be 26,900 Da by SDS-PAGE analysis. The purified enzyme displayed a Km of 220 μM, a Kcat of 21.7 sec(-1) and a Kcat/Km of 98,796 sec(-1) M(-1) with an optimal pH of 9.5 for the Z-GPR-MCA substrate. The protease was totally inhibited by serine protease inhibitors and showed granzymeA-like substrate specificity. Therefore, we conclude that the purified enzyme belongs to the mammalian granzymeA (EC 3.4.21.78) and appears to be involved in cytotoxicity in fish.

Pilot Study of Natural Killer Cells in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis and Multiple Sclerosis

Patients with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and multiple sclerosis (MS) suffer from debilitating fatigue which is not alleviated by rest. In addition to the fatigue-related symptoms suffered by patients with CFS/ME and MS, dysfunction of the immune system and, in particular, reduced natural killer (NK) cell cytotoxic activity has also been reported in CFS/ME and MS. The purpose of this pilot study was to compare NK cellular mechanisms in patients with CFS/ME and MS to investigate potential dysfunctions in the NK cell activity pathway. Flow cytometry protocols assessed CD56(dim) CD16(+) and CD56(bright) CD16(+/-) NK cell expression of adhesion molecules, NK activating and inhibiting receptors, NK cell maturation and lytic proteins. All participants in this study were female and included 14 patients with CFS/ME, nine patients with MS and 19 non-fatigued controls. The patient groups and the non-fatigued controls were not taking any immunosuppressive or immune-enhancing medications. In the MS cohort, KIR2DL5 was significantly increased on CD56(bright) CD16(+/-) NK cells and expression of CD94 was significantly increased on CD56(dim) CD16(+) NK cells in comparison with the controls. Co-expression of CD57 and perforin was significantly increased on CD56(dim) CD16(+) NK cells from patients with CFS/ME compared to the MS and non-fatigued control participants. The results from this pilot study suggest that NK cells from patients with CFS/ME and MS may have undergone increased differentiation in response to external stimuli which may affect different mechanisms in the NK cell cytotoxic activity pathway.

ERK1/2, MEK1/2 and p38 downstream signalling molecules impaired in CD56 dim CD16+ and CD56 bright CD16 dim/- natural killer cells in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis patients

Background

Natural Killer (NK) cell effector functions are dependent on phosphorylation of the mitogen-activated protein kinases (MAPK) pathway to produce an effective immune response for the clearance of target cells infected with viruses, bacteria or malignantly transformed cells. Intracellular signals activating NK cell cytokine production and cytotoxic activity are propagated through protein phosphorylation of MAPKs including MEK1/2, ERK1/2, p38 and JNK. Reduced NK cell cytotoxic activity is consistently reported in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) patients and intracellular signalling by MAPK in NK cells remains to be investigated. Therefore, the purpose of this paper was to investigate MAPK downstream signalling molecules in NK cell phenotypes from CFS/ME patients.

Methods

Flow cytometric protocols were used to measure phosphorylation of the MAPK pathway in CD56^brightCD16^dim/− and CD56^dimCD16⁺ NK cells following stimulation with K562 tumour cells or phorbol-12-myristate-13-acetate plus ionomycin. NK cell cytotoxic activity, degranulation, lytic proteins and cytokine production were also measured as markers for CD56^brightCD16^dim/− and CD56^dimCD16⁺ NK cell function using flow cytometric protocols.

Results

CFS/ME patients (n = 14) had a significant decrease in ERK1/2 in CD56^dimCD16⁺ NK cells compared to the non-fatigued controls (n = 11) after incubation with K562 cells. CD56^brightCD16^dim/− NK cells from CFS/ME patients had a significant increase in MEK1/2 and p38 following incubation with K562 cells.

Conclusions

This is the first study to report significant differences in MAPK intracellular signalling molecules in CD56^dimCD16⁺ and CD56^brightCD16^dim/− NK cells from CFS/ME patients. The current results highlight the importance of intracellular signalling through the MAPK pathway for synergistic effector function of CD56^dimCD16⁺ and CD56^brightCD16^dim/− NK cells to ensure efficient clearance of target cells. In CFS/ME patients, dysfunctional MAPK signalling may contribute to reduced NK cell cytotoxic activity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-0859-z) contains supplementary material, which is available to authorized users.

TOE1 is an inhibitor of HIV-1 replication with cell-penetrating capability

Target of Egr1 (TOE1) is a nuclear protein localized primarily in nucleoli and Cajal bodies that was identified as a downstream target of the immediate early gene Egr1. TOE1 displays a functional deadenylation domain and has been shown to participate in spliceosome assembly. We report here that TOE1 can function as an inhibitor of HIV-1 replication and show evidence that supports a direct interaction of TOE1 with the viral specific transactivator response element as part of the inhibitory mechanism. In addition, we show that TOE1 can be secreted by activated CD8(+) T lymphocytes and can be cleaved by the serine protease granzyme B, one of the main components of cytotoxic granules. Both full-length and cleaved TOE1 can spontaneously cross the plasma membrane and penetrate cells in culture, retaining HIV-1 inhibitory activity. Antiviral potency of TOE1 and its cell-penetrating capability have been identified to lie within a 35-amino-acid region containing the nuclear localization sequence.

Human T cell activation induces synaptic translocation and alters expression of the serine protease inhibitor neuroserpin and its target protease

Contact between T cells and APCs and activation of an effective immune response trigger cellular polarization and the formation of a structured interface known as the immunological synapse. Interactions across the synapse and secretion of T cell and APC-derived factors into the perisynaptic compartment regulate synapse formation and activation of T cells. We report that the serine protease inhibitor neuroserpin, an axonally secreted protein thought to play roles in the formation of the neuronal synapse and refinement of synaptic activity, is expressed in human naïve effector memory and central memory subsets of CD4(+) and CD8(+) T cells, as well as monocytes, B cells, and NK cells. Neuroserpin partially colocalized with a TGN38/LFA-1-positive vesicle population in T cells and translocates to the immunological synapse upon activation with TCR antibodies or antigen-pulsed APCs. Activation of T cells triggered neuroserpin secretion, a rapid, 8.4-fold up-regulation of the serine protease tissue plasminogen activator, the protease target for neuroserpin, and a delayed, 6.25-fold down-regulation of neuroserpin expression. Evidence of polarization and regulated neuroserpin expression was also seen in ex vivo analyses of human lymph nodes and blood-derived T cells. Increased neuroserpin expression was seen in clusters of T cells in the paracortex of human lymph nodes, with some showing polarization to areas of cell:cell interaction. Our results support a role for neuroserpin and tissue plasminogen activator in activation-controlled proteolytic cleavage of proteins in the synaptic or perisynaptic space to modulate immune cell function.

Identification of a novel fish granzyme involved in cell-mediated immunity

Granzymes (Gzms) are serine proteases released from cytoplasmic granules within cytotoxic T lymphocytes and natural killer (NK) cells. Gzms induce apoptosis within virus-infected and transformed cells. In fish as well as mammals, Gzms appear to play a major role in inducing target cell death. However, information on the function of fish Gzms is limited, although Gzm-like genes have been reported in several species. We identified and characterized a fish Gzm (termed gcGzm) in ginbuna crucian carp, Carassius auratus langsdorfii. The primary structure of gcGzm resembled mammalian GzmB, and gcGzm clustered with mammalian GzmB by phylogenetic tree analysis. gcGzm was secreted from HEK293T cells transfected with gcgzm cDNA and was predominantly expressed in CD8(+) T cells, as in mammals. Expression of gcgzm mRNA was greatly enhanced by allo-sensitization and infection with the intracellular pathogen Edwardsiella tarda, indicating that gcGzm is involved in cell-mediated immunity. However, its enzymatic activity was different from mammalian Gzms because gcGzm did not cleave the known substrates for mammalian Gzms. Thus we conclude that the newly discovered gcGzm is a novel secretory serine protease involved in cell-mediated immunity in fish, with similar structure to human GzmB but different substrate specificity.

Identification of phenotypic markers of B cells from patients with Chagas disease

Chagas disease was discovered more than a hundred years ago, but its pathogenesis is still not completely understood. Autoimmunity is one of the mechanisms shown to contribute to its pathogenesis, which may indicate an important participation of B lymphocytes. Patients with Chagas disease have shown increased percentage of B cells producing IL-10. However, there are no reports of the phenotypic markers of B cells producing IL-10 in patients with Chagas disease. For the first time in the literature, we evaluated the phenotypic profile of distinct markers of B cells from peripheral blood of noninfected individuals and patients with Chagas disease. Our results showed that patients with Chagas disease had a higher expression of CD21 and CD24 on the surface of CD19+ B cells, while CD43 and CD23 were expressed equally in all groups. Moreover, the expression of MHC-II (HLA-DR), CD80, CD86, caspase-3, granzyme B and intracellular IL-10 and TGF-β by CD19+ B cells was higher in patients with Chagas disease. The results of IL-10 production within CD19+ CD5+ CD1d+ B cells showed a higher percentage of this cytokine in patients with Chagas disease. Thus, our data bring a new knowledge about distinct markers of B cells in immune responses of Chagas disease.

Granzyme M as a novel effector molecule for human cytolytic fusion proteins: CD64-specific cytotoxicity of Gm-H22(scFv) against leukemic cells

Immunotoxins are promising targeted therapeutic agents comprising an antibody-based ligand that specifically binds to diseased cells, and a pro-apoptotic protein. Toxic components from bacteria or plants can trigger a neutralizing immune response, so that human effector molecules are more suitable. In this context, the protease granzyme B has been successfully tested in cytotoxicity assays against different cancer cells in vitro and in vivo. Our aim here was to introduce granzyme M as an alternative and novel component of human cytolytic fusion proteins. We fused it to the humanized single-chain antibody fragment (scFv) H22 which specifically binds to CD64, an FcγRI receptor overexpressed on activated myeloid cells and leukemic cells. We show that the humanized cytolytic fusion protein Gm-H22(scFv) specifically targets the acute myeloid leukemia cell line HL60 in vitro and is cytotoxic with an IC50 between 1.2 and 6.4 nM. These findings were confirmed ex vivo using leukemic primary cells from patients, which were killed by granzyme M despite the presence of the granzyme B inhibitor serpin B9. In conclusion, granzyme M is a promising new cell-death inducing component for hCFPs because it specifically and efficiently kills target cells when fused to a targeting component.

Serum concentrations of metalloproteinase 2, metalloproteinase 9 and granzyme B in contact eczema patients

Introduction

Contact eczema is a common skin condition with complex etiology, variable clinical presentation and lengthy therapy duration. The mechanism of contact eczema is complex, since it is affected by multiple inflammatory mediators.

Aim

To assess concentrations of metalloproteinase 2 (MMP-2), metalloproteinase 9 (MMP-9) and granzyme B (GzmB) in patients with contact eczema.

Material and methods

Seventy patients with contact eczema and 30 healthy persons as controls were included in the study. In all subjects, MMP-2, MMP-9 and GzmB were determined using ELISA immunoassay. In study group patients, concentrations were assayed in periods of disease exacerbation and remission. Obtained results were analyzed statistically.

Results

Mean MMP-2 and GzmB concentrations were found to be significantly higher in the study group than in the control group. Mean MMP-2, MMP-9 and GzmB levels were also statistically significantly higher during skin lesion relapse compared to contact eczema remission periods.

Conclusions

The presented paper demonstrates that MMP-2, MMP-9 and GzmB are good markers of contact eczema exacerbations.

Expression of endometrial immune-related genes possibly functioning during early pregnancy in the mare

Despite enormous efforts, biochemical and molecular mechanisms associated with equine reproduction, particularly processes of pregnancy establishment, have not been well characterized. Previously, PCR-selected suppression subtraction hybridization analysis was executed to identify unique molecules functioning in the equine endometrium during periods of pregnancy establishment, and granzyme B (GZMB) cDNA was found in the pregnant endometrial cDNA library. Because GZMB is produced from natural killer (NK) cells, endometrial expression of GZMB and immune-related transcripts were characterized in this study. The level of GZMB mRNA is higher in the pregnant endometrium than in non-pregnant ones. This expression was also confirmed through Western blot and immunohistochemical analyses. IL-2 mRNA declined as pregnancy progressed, while IL-15, IFNG and TGFB1 transcripts increased on day 19 and/or 25. Analyses of IL-4 and IL-12 mRNAs demonstrated the increase in these transcripts as pregnancy progressed. Increase in CCR5 and CCR4 mRNAs indicated that both Th1 and Th2 cells coexisted in the day 25 pregnant endometrium. Taken together, the endometrial expression of immune-related transcripts suggests that immunological responses are present even before the trophectoderm actually attaches to the uterine epithelial cells.

Ulinastatin improves survival of septic mice by suppressing inflammatory response and lymphocyte apoptosis

BACKGROUND

Sepsis involves imbalance between the proinflammatory and antiinflammatory response to bacterial insults. Ulinastatin (UTI) is a serine protease inhibitor and reportedly exhibits antiinflammatory properties aside from its blocking of the protease pathway both in vitro and in vivo. This study was designed to investigate the potential therapeutic efficacy of UTI for sepsis.

MATERIALS AND METHODS

Adult C57BL/6 male mice were divided into three groups: sham group, cecal ligation and puncture (CLP) group, and CLP + UTI group. Acute septic peritonitis was induced by CLP. Saline and UTI (100,000 U/kg) were intravenously injected 30 min after CLP in CLP and CLP + UTI groups, respectively. Samples were collected for further analysis 24 h after surgery.

RESULTS

UTI administration significantly improved 7-d survival; ameliorated morphologic damage and weight loss in the spleen and thymus; decreased serum tumor necrosis factor α, interleukin-6, and interleukin-10 (IL-10) levels; increased the number of T and B cells in peripheral blood, spleen, and thymus; and inhibited T-cell apoptosis in the thymus and spleen in septic mice.

CONCLUSIONS

UTI exerted a protective effect against sepsis by suppressing inflammatory response and lymphocyte apoptosis.

Role of serine proteases in inflammation: Bowman-Birk protease inhibitor (BBI) as a potential therapy for autoimmune diseases

Serine proteases, a sub-category of the protease family, participate in various physiologic and pathologic conditions. Serine proteases are involved in different arms of the immune system and play an important role in inflammation. They have been evaluated as therapeutic targets in several inflammatory diseases. The Bowman-Birk protease inhibitor (BBI), a soybean-derived serine protease inhibitor, is resistant to temperature and acidic conditions. These characteristics make it a good candidate for oral administration, with no major side effects. In addition, the therapeutic effect of BBI has been shown in inflammatory diseases and cancer. We have demonstrated the immunoregulatory and anti-inflammatory effects of BBI in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis. Here we review the role of serine proteases in inflammatory diseases, with emphasis on the potential of BBI as a novel oral therapy for multiple sclerosis.

Selective cytotoxicity of amidinopiperidine based compounds towards Burkitt's lymphoma cells involves proteasome inhibition

Serine proteases have proven to be promising pharmacological targets in contemporary drug discovery for cancer treatment. Since azaphenylalanine-based compounds manifest cytotoxic activity, we have selected serine protease inhibitors designed and synthesized in-house with large hydrophobic naphthalene moiety for screening. The cytotoxic potential of screened molecules was correlated to modifications of R¹ residues. The most cytotoxic were compounds with greater basicity; amidinopiperidines, piperidines and benzamidines. Amidinopiperidine-based compounds exert cytotoxicity in low µM range, with IC₅₀ 18 µM and 22 µM for inhibitors 15 and 16 respectively. These compounds exhibited selective cytotoxicity towards the Burkitt’s lymphoma cells Ramos and Daudi, and proved nontoxic to PMBC, Jurkat and U937. They induce caspase-dependent apoptotic cell death, as demonstrated by the use of a pan-caspase inihibitor, zVADfmk, which was able to rescue Ramos cells from compound(s)-induced apoptosis. We confirm a disruption of the pro-survival pathway in Burkitt’s lymphoma through NFκB inhibition. The accumulation of phosphorylated precursor (p105) and inhibitory (IκB) molecules with no subsequent release of active NFκB implicated the involvement of proteasome. Indeed, we show that the amidinopiperidine-based compounds inhibit all three proteolytical activities of the human 20S proteasome, with the most prominent effect being on the trypsin-like activity. Consistently, treatment of Ramos cells with these compounds led to an increase in ubiquitinated proteins. The amidinopiperidine-based serine protease inhibitors presented are, as selective inducers of apoptosis in Burkitt’s lymphoma cells, promising leads for the development of novel chemotherapeutics.

Implication of caspase-3 and granzyme B expression and activity in spleenocytes of ehrlich ascites carcinoma mice subjected to immunotherapy

Background

Caspase-3 and granzyme B were claimed as apoptotic manipulative enzymes.

Aims

The present study was to determine the enzymes expression and activity in cancer and cancer immune therapeutic status and the possible association to cancer common pathological signs targeting the improvement of therapeutic conditions.

Material and Methods

Mice were immunized with cell lyaste or cell lysate + CKI in the right thigh and challenged with live cells of ehrlich ascites carcinoma (EAC) in the left thigh. The expression and activity of both enzymes in the spleenocytes derived from different subjects (normal, EAC and cell lysate or cell lysate + CKI immunized mice) after cultured with EAC viable cells were determined by colorimetric assay and western blot analysis. In addition, the subjects DNA ladder and serum metalloproteases (MMP 2 and 9) zymography were observed.

Results

The experimental data revealed over expression of caspase3 and granzyme B in the groups of cell lysate or cell lysate + CKI immunized mice compared to control while down expression were recorded in the EAC subject. The over expression of the 2 enzymes were accompanied with increases in the activities of caspase3 and granzyme B, changes in DNA fragmentation and inhibition of metalloproteases.

Conclusion

It could be suggested that, the parameter estimation within the present experimental framework could identify the efficiency of therapeutic vaccine protocols and elucidate the impact of CKI adjuvant with vaccines therapy.

Proteases implicated in apoptosis: old and new

OBJECTIVES

The role of proteases in the regulation of apoptosis is becoming increasingly apparent. Whilst many of these proteases are already characterised, some have yet to be identified. Traditionally caspases held the traditional role as the prime mediators of apoptosis; however, attention is now turning towards the contribution made by serine proteases.

KEY FINDINGS

As unregulated apoptosis is implicated in various disease states, the emergence of this proteolytic family as apoptotic regulators offers novel and alterative opportunities for therapeutic targets.

SUMMARY

This review presents a brief introduction and overview of proteases in general with particular attention given to those involved in apoptotic processing.

PARP-1 cleavage fragments: signatures of cell-death proteases in neurodegeneration

The normal function of poly (ADP-ribose) polymerase-1 (PARP-1) is the routine repair of DNA damage by adding poly (ADP ribose) polymers in response to a variety of cellular stresses. Recently, it has become widely appreciated that PARP-1 also participates in diverse physiological and pathological functions from cell survival to several forms of cell death and has been implicated in gene transcription, immune responses, inflammation, learning, memory, synaptic functions, angiogenesis and aging. In the CNS, PARP inhibition attenuates injury in pathologies like cerebral ischemia, trauma and excitotoxicity demonstrating a central role of PARP-1 in these pathologies. PARP-1 is also a preferred substrate for several 'suicidal' proteases and the proteolytic action of suicidal proteases (caspases, calpains, cathepsins, granzymes and matrix metalloproteinases (MMPs)) on PARP-1 produces several specific proteolytic cleavage fragments with different molecular weights. These PARP-1 signature fragments are recognized biomarkers for specific patterns of protease activity in unique cell death programs. This review focuses on specific suicidal proteases active towards PARP-1 to generate signature PARP-1 fragments that can identify key proteases and particular forms of cell death involved in pathophysiology. The roles played by some of the PARP-1 fragments and their associated binding partners in the control of different forms of cell death are also discussed.

Characterizing the anti-tumor function of adoptively transferred NK cells in vivo

Natural killer (NK) cells represent a promising cell type to utilize for effective adoptive immunotherapy. However, little is known about the important cytolytic molecules and signaling pathways used by NK cells in the adoptive transfer setting. To address this issue, we developed a novel mouse model to investigate the trafficking and mechanism of action of these cells. We demonstrate that methylcholanthrene-induced RKIK sarcoma cells were susceptible to NK cell-mediated lysis in vitro and in vivo following adoptive transfer of NK cells in C57BL/6 RAG-2(-/-)gammac(-/-) mice. Cytotoxic molecules perforin, granzymes B and M as well as the death ligand TRAIL and pro-inflammatory cytokine IFN-gamma were found to be important in the anti-tumor effect mediated by adoptively transferred NK cells. Importantly, we demonstrate that adoptively transferred NK cells could traffic to the tumor site and persisted in vivo which correlated with the anti-tumor effect observed. Overall, the results of this study have important implications for enhancing NK cell-based immunotherapies.

Orphan granzymes find a home

Cytotoxic lymphocytes are armed with granules that are released in the granule-exocytosis pathway to kill tumor cells and virus-infected cells. Cytotoxic granules contain the pore-forming protein perforin and a family of structurally homologues serine proteases called granzymes. While perforin facilitates the entry of granzymes into a target cell, the latter initiate distinct apoptotic routes. Granzymes are also implicated in extracellular functions such as extracellular matrix degradation, immune regulation, and inflammation. The family of human granzymes consists of five members, of which granzyme A and B have been studied most extensively. Recently, elucidation of the specific characteristics of the other three human granzymes H, K, and M, also referred to as orphan granzymes, have started. In this review, we summarize and discuss what is currently known about the biology of the human orphan granzymes.

Activated T-cells inhibit neurogenesis by releasing granzyme B: rescue by Kv1.3 blockers

There is a great need for pharmacological approaches to enhance neural progenitor cell (NPC) function particularly in neuroinflammatory diseases with failed neuroregeneration. In diseases such as multiple sclerosis and stroke, T-cell infiltration occurs in periventricular zones where NPCs are located and is associated with irreversible neuronal loss. We studied the effect of T-cell activation on NPC functions. NPC proliferation and neuronal differentiation were impaired by granzyme B (GrB) released by the T-cells. GrB mediated its effects by the activation of a Gi-protein-coupled receptor leading to decreased intracellular levels of cAMP and subsequent expression of the voltage-dependent potassium channel, Kv1.3. Importantly, blocking channel activity with margatoxin or blocking its expression reversed the inhibitory effects of GrB on NPCs. We have thus identified a novel pathway in neurogenesis. The increased expression of Kv1.3 in pathological conditions makes it a novel target for promoting neurorestoration.

Granzyme-b is involved in mediating post-ischemic neuronal death during focal cerebral ischemia in rat model

Although peripheral immune cells infiltrate ischemic infarct tissue and elicit immune injury, the role of Cytotoxic T Lymphocytes (CTLs) and the toxins they release in mediating neuronal death is not well understood. Granzyme-b (Gra-b), a serine protease found in the cytoplasmic granules of CTLs and natural killer cells, plays an important role in inducing target cell death by activating several caspases and by initiating caspase-independent pathways that contribute to target cell death. To determine if CTLs and Gra-b are involved in post-ischemic cerebral cell death; we investigated the role of CD8(+) CTLs and Gra-b in ischemic rat brain infarct after transient middle cerebral artery occlusion (tMCAO) and in sham-operated animals. We observed that CTLs infiltrate the ischemic infarct within 1 h of reperfusion. There was a significant increase in Gra-b levels in the ischemic region starting from 1 h until 3 day which correlated with increased levels of chemokines (IP-10/CXCL10, IL-2) and TNF-alpha. Co-immunoprecipitation experiments show that Gra-b interacts with Bid, PARP, and caspase-3 in ischemic samples. Immunofluorescence analysis of Gra-b and TUNEL showed that Gra-b is present both in apoptotic and necrotic cells. Triple immunostaining further confirmed that the Gra-b positive degenerating cells were neurons. CTLs in close spatial proximity to degenerating neurons, increased levels of Gra-b, localization in neurons positive for TUNEL, and interaction with other pro-apoptotic proteins indicate that Gra-b and CTLs play a significant role in neuronal death following cerebral ischemia in the rat brain after tMCAO. Based on the above findings we support our hypothesis that Gra-b secreted from activated CTLs might be involved in aggravating post-ischemic damage by mediating neuronal death.

Altered effector function of peripheral cytotoxic cells in COPD

Background

There is mounting evidence that perforin and granzymes are important mediators in the lung destruction seen in COPD. We investigated the characteristics of the three main perforin and granzyme containing peripheral cells, namely CD8⁺ T lymphocytes, natural killer (NK; CD56⁺CD3^-) cells and NKT-like (CD56⁺CD3⁺) cells.

Methods

Peripheral blood mononuclear cells (PBMCs) were isolated and cell numbers and intracellular granzyme B and perforin were analysed by flow cytometry. Immunomagnetically selected CD8+ T lymphocytes, NK (CD56⁺CD3^-) and NKT-like (CD56⁺CD3⁺) cells were used in an LDH release assay to determine cytotoxicity and cytotoxic mechanisms were investigated by blocking perforin and granzyme B with relevant antibodies.

Results

The proportion of peripheral blood NKT-like (CD56⁺CD3⁺) cells in smokers with COPD (COPD subjects) was significantly lower (0.6%) than in healthy smokers (smokers) (2.8%, p < 0.001) and non-smoking healthy participants (HNS) (3.3%, p < 0.001). NK (CD56⁺CD3^-) cells from COPD subjects were significantly less cytotoxic than in smokers (16.8% vs 51.9% specific lysis, p < 0.001) as were NKT-like (CD56⁺CD3⁺) cells (16.7% vs 52.4% specific lysis, p < 0.001). Both cell types had lower proportions expressing both perforin and granzyme B. Blocking the action of perforin and granzyme B reduced the cytotoxic activity of NK (CD56⁺CD3^-) and NKT-like (CD56⁺CD3⁺) cells from smokers and HNS.

Conclusion

In this study, we show that the relative numbers of peripheral blood NK (CD56⁺CD3^-) and NKT-like (CD56⁺CD3⁺) cells in COPD subjects are reduced and that their cytotoxic effector function is defective.

The serpin saga; development of a new class of virus derived anti-inflammatory protein immunotherapeutics

Serine proteinase inhibitors, also called serpins, are an ancient grouping of proteins found in primitive organisms from bacteria, protozoa and horseshoe crabs and thus likely present at the time of the dinosaurs, up to all mammals living today. The innate or inflammatory immune system is also an ancient metazoan regulatory system, providing the first line of defense against infection or injury. The innate inflammatory defense response evolved long before acquired, antibody dependent immunity. Viruses have developed highly effective stratagems that undermine and block a wide variety of host inflammatory and immune responses. Some of the most potent of these immune modifying strategies utilize serpins that have also been developed over millions of years, including the hijacking by some viruses for defense against host immune attacks. Serpins represent up to 2-10 percent of circulating plasma proteins, regulating actions as wide ranging as thrombosis, inflammation, blood pressure control and even hormone transport. Targeting serpin-regulated immune or inflammatory pathways makes evolutionary sense for viral defense and many of these virus-derived inhibitory proteins have proven to be highly effective, working at very low concentrations--even down to the femptomolar to picomolar range. We are studying these viral anti-inflammatory proteins as a new class of immunomodulatory therapeutic agents derived from their native viral source. One such viral serpin, Serp-1 is now in clinical trial (conducted by VIRON Therapeutics, Inc.) for acute unstable coronary syndromes (unstable angina and small heart attacks), representing a 'first in class' therapeutic study. Several other viral serpins are also currently under investigation as anti-inflammatory or anti-immune therapeutics. This chapter describes these original studies and the ongoing analysis of viral serpins as a new class of virus-derived immunotherapeutic.

Granzyme C supports efficient CTL-mediated killing late in primary alloimmune responses

It is well established that granzymes A and B play a role in CTL killing of target cells by the perforin-dependent granule exocytosis pathway. The functions of multiple additional granzymes expressed in CTL are less well defined. In the present studies, CTL generated from mice deficient in dipeptidyl peptidase 1 (DPP1) were used to investigate the contribution of granzyme C to CTL killing of allogeneic target cells. DPP1 is required for activation of granzymes A and B by proteolytic removal of their N-terminal dipeptide prodomains while a significant portion of granzyme C is processed normally in the absence of DPP1. Cytotoxicity of DPP1(-/-) CTL generated in early (5-day) MLC in vitro and in peritoneal exudate cells 5 days after initial allogeneic sensitization in vivo was significantly impaired compared with wild-type CTL. Following 3 days of restimulation with fresh allogeneic stimulators however, cytotoxicity of these DPP1(-/-) effector cells was comparable to that of wild-type CTL. Killing mediated by DPP1(-/-) CTL following restimulation was rapid, perforin dependent, Fas independent and associated with early mitochondrial injury, phosphatidyl serine externalization, and DNA degradation, implicating a granzyme-dependent apoptotic pathway. The increased cytotoxicity of DPP1(-/-) CTL following restimulation coincided with increased expression of granzyme C. Moreover, small interfering RNA inhibition of granzyme C expression during restimulation significantly decreased cytotoxicity of DPP1(-/-) but not wild-type CTL. These results indicate that during late primary alloimmune responses, granzyme C can support CTL-mediated killing by the granule exocytosis pathway in the absence of functional granzymes A or B.

Granzymes drive a rapid listeriolysin O-induced T cell apoptosis

The Listeria monocytogenes protein listeriolysin O (LLO) is a pore-forming protein essential for virulence. Although the major role for LLO is to allow L. monocytogenes entry into the cytosol, it also induces apoptosis of activated lymphocytes, an obligatory cellular response that modulates the infection. Induction of apoptosis by LLO proceeds through a fast, caspase-dependent pathway and a slow, caspase-independent pathway. Polyclonal T cell lines were generated from either normal mice or mice deficient in granzyme and perforin proteins, and then treated with apoptogenic doses of LLO. In this study we show that apoptosis of lymphocytes induced by LLO was characterized by activation of caspases as quickly as 30 min that was dependent on the expression of granzymes. In the absence of granzymes, all parameters of apoptosis such as caspase activation, phosphatidylserine exposure, mitochondrial depolarization, and DNA fragmentation were dramatically reduced in magnitude. Removal of perforin inhibited the apoptotic effect of LLO on cells by approximately 50%. Neutralization of intracellular acidification using chloroquine inhibited the rapid apoptotic death. In agreement with these findings granzyme-deficient mice harbored lower bacterial titers and decrease splenic pathology compared with normal mice following L. monocytogenes infection. Thus, LLO exploits apoptotic enzymes of the adaptive immune response to eliminate immune cells and increase its virulence.

Preoperative treatment with a non-steroidal anti-inflammatory drug (NSAID) increases tumor tissue infiltration of seemingly activated immune cells in colorectal cancer

This study evaluates HLA gene expression and tumor infiltration by B-cells, macrophages, dendritic cells, T-helper and cytotoxic T-lymphocytes in response to short-term preoperative treatment with cyclooxygenase inhibitors. Patients with colorectal carcinoma were randomized to receive oral NSAID (indomethacin or celebrex) for three days preoperatively; controls received esomeprazol. Peroperative tumor biopsies and normal colon tissue were analyzed by microarray, quantitative PCR and immunohistochemistry. Efficacy of short-term systemic NSAID treatment was confirmed by measurement of PGE2 production in blood monocytes from healthy volunteers. NSAID treatment upregulated genes at the MHC locus on chromosome 6p21 in tumor tissue, but not in normal colon tissue, from the same patient. 23 of the 100 most upregulated genes belonged to MHC class II. HLA-DM, -DO (peptide loading), HLA-DP, -DQ, -DR (antigen presentation), granzyme B, H, perforin and FCGR3A (CD16) (cytotoxicity) displayed increased expression, as did CD8, a marker of cytotoxic T-lymphocytes, while HLA-A and -C expression were not increased by NSAID treatment. MHC II protein (HLA-DP, -DQ, -DR) levels and infiltration by CD4+ T-helper cells of tumor stroma increased upon NSAID treatment, while CD8+ cytotoxic T-lymphocytes increased in both tumor stroma and epithelium. Molecules associated with immunosuppressive T regulatory cells (FOXP3, IL-10) were significantly decreased in indomethacin-exposed tumors. Standard oral administration of NSAID three days preoperatively was enough to increase tumor infiltration by seemingly activated immune cells. These findings agree with previous information that high prostanoid activities in colorectal cancer increase the risk for reduced disease-specific survival following tumor resection.

Expression of granzyme B in peripheral blood polymorphonuclear neutrophils (PMN), myeloid cell lines and in PMN derived from haemotopoietic stem cells in vitro

Granzyme B and perforin are the major protagonists of cytotoxicity mediated by natural killer (NK) cells or cytotoxic T cells. More recent we described the presence of granzyme B and perforin in polymorphonuclear neutrophils (PMN), a finding in discrepancy with the credo that granzyme B and perforin expression is restricted to cytotoxic T cells and NK cells. In extension of our previous study, we now provide evidence that granzyme B is not only present in mature PMN, but also in the myeloid cell lines HL-60 and U937, in CD34+ stem cells, and in PMN derived from CD34+ cells in vitro. In agreement with the "targeting by time" hypothesis we found the bulk of granzyme B in association with primary granules, in addition to a minor membrane expression. Granzyme B, on one hand might, enhance the cytotoxic potential of PMN, on the other, it may provide PMN with additional means to degrade extracellular matrices.

Gene Expression Time Course in the Human Skin during Elicitation of Allergic Contact Dermatitis

Genes involved in the inflammatory response resulting in allergic contact dermatitis (ACD) are only partly known. In this study, we introduce the use of high-density oligonucleotide arrays for gene expression profiling in human skin during the elicitation of ACD. Skin biopsies from normal and nickel-exposed skin were obtained from seven nickel-allergic patients and five nonallergic controls at four different time points during elicitation of eczema. Each gene expression profile was analyzed by hybridization to high-density oligonucleotide arrays. Cluster analysis of 74 genes found to be differentially expressed in the patients over time revealed that the patient samples may be categorized into two groups: an early time-point group (no clinical reaction) and a late time-point group (clinical reaction). Bioinformatics analyses unraveled the potential involvement of signal transducers and activator of transcription and small/mothers against decepentaplegic (SMAD) transcription factors in the late time-point gene expression patterns. Concerning specific genes, the homeostatic chemokine CCL19 was unexpectedly found to be highly expressed in cells scattered in the deep dermis of the late time-point samples. Taken together, these findings suggest hitherto unknown roles of SMAD transcription factors and of CCL19 in the elicitation phase of ACD.

A more serine way to die: defining the characteristics of serine protease-mediated cell death cascades

The morphological features observed by Kerr, Wylie and Currie in 1972 define apoptosis, necrosis and autophagy. An appreciable number of alternative systems do not fall neatly under these categories, warranting a review of alternative proteolytic machinery and its contribution to cell death. This review aims to pinpoint key molecular features of serine protease-mediated pro-apoptotic signalling. The profile created will contribute to a standard set of biochemical criteria that can serve in differentiating within cell death subtypes.

Identification and characterization of equine granzyme B

In the present study we describe the isolation and characterization of putative equine granzyme B for which we propose the designation 'eqGrzmB'. Sequence analysis revealed characteristic features of a GrzmB protease such as the presence of a signal (leader-) peptide and an activation di-peptide. The isolated eqGrzmB is functionally active when expressed in human or in insect cells. Furthermore, exchange of any of three putative active site amino acids, which are highly conserved along granzyme B enzymes, led to a complete loss of enzymatic activity in the newly identified eqGrzmB. Phylogenetic analysis places eqGrzmB in the chymase-locus within the large family of granzymes in close proximity to putative equine mast cell protease and to granzyme B from mouse, rat, and human. eqGrzmB proteolytic activity has been kinetically characterized and can be specifically inhibited by granzyme B inhibitors. Taken together, we conclude that we have isolated a new member of the granzyme B family, the first granzyme identified in Equidae. The description of equine granzyme B might facilitate the development of immunological assays for the activity of equine lymphocytes.

The emerging role of serine proteases in apoptosis

Unregulated apoptosis can be due to a disruption in the balance and control of both intra- and inter-cellular proteolytic activities leading to various disease states. Many proteases involved in apoptotic processes are yet to be identified; however, several are already well characterized. Caspases traditionally held the predominant role as prime mediators of execution. However, latterly, evidence has accumulated that non-caspases, including calpains, cathepsins, granzymes and the proteasome have roles in mediating and promoting cell death. Increasingly, research is implicating serine proteases within apoptotic processing, particularly in the generation of nuclear events such as condensation, fragmentation and DNA degradation observed in late-stage apoptosis. Serine proteases therefore are emerging as providing additional or alternative therapeutic targets.

Brucella requires a functional Type IV secretion system to elicit innate immune responses in mice

The virB operon, encoding a Type IV secretion system (T4SS), is essential for intracellular survival and persistent infection by Brucella spp. To better understand the role of the T4SS in evading host defence mechanisms and establishing chronic infection, we compared transcriptional profiles of the host response to infection with wild-type and virB mutant Brucella strains. Analysis of gene expression profiles in murine splenocytes 3 days after inoculation with wild-type Brucella strains revealed an inflammatory response, with a prominent upregulation of genes induced by both type I and type II interferons. Real-time RT-PCR showed that a group of genes from these pathways were induced by day 3 post infection and declined to baseline levels by day 7. In contrast, neither of the two virB mutant strains elicited a proinflammatory gene expression profile, demonstrating that the T4SS was required to trigger this response. Infection studies using type I interferon receptor knockout mice showed that a lack of type I interferon signalling did not affect Brucella replication during the first 4 weeks of infection. Thus, induction of type I interferons does not appear to be an essential mechanism by which the T4SS promotes persistent infection by Brucella.

Bikunin (Urinary Trypsin Inhibitor): Structure, Biological Relevance, And Measurement

Inflammatory processes, such as phagocytosis, coagulation, and vascular dilation, promote the release of serine proteases by neutrophils, macrophages, mast cells, lymphocytes, and the epithelial or endothelial cells. These proteases further facilitate the release of inflammatory cytokines and growth factors as well as take part in signal-cell proliferation through protease-activated receptors (PARs). Controlling the action of this cascade is necessary to prevent further damage to the normal tissues. One of the main anti-inflammatory response mediators is bikunin (Bik) that is responsible for inhibiting the activity of many serine proteases such as trypsin, thrombin, chymotrypsin, kallikrein, plasmin, elastase, cathepsin, Factors IXa, Xa, XIa, and XlIa. During the acute-phase response, Bik is released into plasma from proinhibitors primarily due to increased elastase activity. Bik is a glycoprotein, also referred to as urinary trypsin inhibitor, which in plasma inhibits the trypsin family of serine proteases by binding to either of the two Kunitz-binding domains. Bik also accumulates in urine. In conditions such as infection, cancer, tissue injury during surgery, kidney disease, vascular disease, coagulation, and diabetes, the concentrations of Bik in plasma and urine are increased. Several trypsin inhibitory assays for urine and immunoassays for both blood and urine have been described for measuring Bik. In addition to presenting the synthesis, structure, and pathophysiology of Bik, we will summarize various diagnostic approaches for measuring Bik. Analysis of Bik may provide a rapid approach in assessing various conditions involving the inflammatory processes.

Glucocorticoid-induced alternative promoter usage for a novel 5' variant of granzyme A

Glucocorticoids exert diverse physiological functions through transcriptional regulation of genes including granzyme A (GZMA). GZMA is one of the apoptotic effectors localized in cytotoxic T lymphocytes and is considered to mediate glucocorticoid-induced apoptosis of human leukemia 697 cells. In the present study, we identified a novel 5' variant transcript of GZMA in dexamethasone (DEX)-treated 697 cells. We designated this novel transcript as GZMAbeta. The transcription of GZMAbeta starts at 290 bp downstream of the first intronic glucocorticoid response element (GRE). Chromatin immunoprecipitation assay showed that glucocorticoid receptor (GR) binds to the intronic GRE in a DEX-dependent manner. Luciferase assay and RT-PCR also showed that DEX induces GZMAbeta transcription mediated by GR binding to the intronic GRE. Our results show that there exist at least two transcripts in human GZMA, whose expression is differentially regulated by glucocorticoid.

Natural killer cells in viral infection: more than just killers

Innate immunity was believed originally to serve simply as the first-line defense against infection and malignancy, with adaptive immunity imposing specificity and ensuring that appropriate responses are mounted against chronic or reoccurring challenges. In this model of immunity, innate and adaptive immune responses are sequential, essentially non-overlapping, and interactions between components of each response limited or non-existent. Over the last 5 years, it has become increasingly evident that interactions between elements of the innate and adaptive immune systems are common. Indeed, it is now clear that the generation and maintenance of effective immunity require an extensive array of interactions between multiple components of the immune system. This review discusses recent advances in this area with particular emphasis on the role of natural killer cells in shaping the adaptive immune response to viral infection.