Cleavage by granzyme B is strongly predictive of autoantigen status: implications for initiation of autoimmunity

Systemic autoimmune diseases are a genetically complex, heterogeneous group of disorders in which the immune system targets a diverse but highly specific group of intracellular autoantigens. The molecules targeted are not unified by common structure, function, or distribution in control cells but become clustered and concentrated in surface blebs when cells undergo apoptosis. We show here that the majority of autoantigens targeted across the spectrum of human systemic autoimmune diseases are efficiently cleaved by granzyme B in vitro and during cytotoxic lymphocyte granule-induced death, generating unique fragments not observed during any other form of apoptosis. These molecules are not cleaved by caspase-8, although this protease has a very similar specificity to granzyme B. The granzyme B cleavage sites in autoantigens contain amino acids in the P(2) and P(3) positions that are preferred by granzyme B but are not tolerated by caspase-8. In contrast to autoantigens, nonautoantigens are either not cleaved by granzyme B or are cleaved to generate fragments identical to those formed in other forms of apoptosis. The striking ability of granzyme B to generate unique fragments is therefore an exclusive property of autoantigens and unifies the majority of molecules targeted in this spectrum of diseases. These results focus attention on the role of the cytotoxic lymphocyte granule-induced death pathway in the initiation and propagation of systemic autoimmunity.

Granzyme B directly and efficiently cleaves several downstream caspase substrates: implications for CTL-induced apoptosis

Caspase-mediated proteolysis of downstream substrates is a critical element of the execution pathway common to all forms of apoptosis studied to date. While this caspase-dependent pathway is activated during cytotoxic lymphocyte granule-induced cell death, recent studies have also provided evidence for caspase-independent pathways. However, the mechanisms mediating these additional pathways have not been defined. The current study demonstrates that DNA-PKcs and NuMA are directly and efficiently cleaved by granzyme B in vitro and in vivo, generating unique substrate fragments not observed during other forms of apoptosis. This direct, caspase-independent ability of granzyme B to cleave downstream death substrates constitutes an apoptotic effector mechanism that is insensitive to inhibitors of the signaling or execution components of the endogenous apoptotic cascade.

Principles for Sustainable Governance of the Oceans

Pressures being exerted on the ocean ecosystems through overfishing, pollution, and environmental and climate change are increasing. Six core principles are proposed to guide governance and use of ocean resources and to promote sustainability. Examples of governance structures that embody these principles are given.

Establishment of a triple co-culture in vitro cell models to study intestinal absorption of peptide drugs

In vitro cell culture models for studying oral drug absorption during early stages of drug development have become a useful tool in drug discovery and development, with respect to substance throughput and reproducibility. The aim of this study was to establish an in vitro cellular model based on human colon carcinoma Caco-2, mucus-producing HT29, and Raji B cells in order to design a model that more accurately mimics the small intestinal epithelial layer. Normal oriented model was set up by seeding co-cultures of Caco-2 and HT29 cells into Transwell filters and maintained under identical conditions following addition of Raji B to the basolateral chamber. Inverted model was set up seeding Caco-2 and HT29 cells on the basolateral chamber and then transferred in the Transwell device with the epithelial cells facing the basolateral chamber following Raji B addition to the apical compartment. Morphological differences on size and thickness of cell membranes were detected between the models studied by using fluorescence microscopy. On the triple co-culture models, cell membranes were increasing in size and thickness from the Caco-2 to Caco-2/HT29 and Caco-2/Raji B. Also, the nuclei seem to be larger than in the other studied models. Insulin permeation was higher on the triple co-culture model when compared to the Caco-2/HT29 co-culture model. Also, insulin permeation as mediated by nanoparticles and insulin solution permeation was higher on the normal oriented Caco-2/HT29/Raji B model as compared to the inverted model. Overall, our results suggest that Caco-2/HT29/Raji B triple co-culture normal oriented cellular model may be reliable to obtain a more physiological, functional, and reproducible in vitro model of the intestinal barrier to study protein absorption, both in solution and when delivered by nanocarriers.

Lipid-based nanovesicles for nanomedicine

Multifunctional lipid-based nanovesicles (L-NVs) prepared by molecular self-assembly of membrane components together with (bio)-active molecules, by means of compressed CO₂-media or other non-conventional methods lead to highly homogeneous, tailor-made nanovesicles that are used for advanced nanomedicine. Confocal microscopy image of siRNA transfection using L-NVs, reprinted with permission from de Jonge,et al.,Gene Therapy, 2006,13, 400–411.

Nanotechnology and pulmonary delivery to overcome resistance in infectious diseases

Used since ancient times especially for the local treatment of pulmonary diseases, lungs and airways are a versatile target route for the administration of both local and systemic drugs. Despite the existence of different platforms and devices for the pulmonary administration of drugs, only a few formulations are marketed, partly due to physiological and technological limitations.

Respiratory infections represent a significant burden to health systems worldwide mainly due to intrahospital infections that more easily affect immune-compromised patients. Moreover, tuberculosis (TB) is an endemic infectious disease in many developing nations and it has resurged in the developed world associated with the human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic.

Currently, medicine faces the specter of antibiotic resistance. Besides the development of new anti-infectious drugs, the development of innovative and more efficient delivery systems for drugs that went off patent appears as a promising strategy pursued by the pharmaceutical industry to improve the therapeutic outcomes and to prolong the utilities of their intellectual property portfolio. In this context, nanotechnology-based drug delivery systems (nano-DDS) emerged as a promising approach to circumvent the limitations of conventional formulations and to treat drug resistance, opening the hypothesis for new developments in this area.

Acute neurogenic pulmonary edema: case reports and literature review

Neurogenic pulmonary edema (NPE) is an underdiagnosed clinical entity. Its pathophysiology is multifactorial but largely unknown. We report two cases of NPE and review the literature on NPE cases reported since 1990. A 21-year-old man had a seizure episode following cranioplasty. He became increasingly dyspneic, and clinical and laboratory signs of respiratory failure were evident. Chest radiography and computed tomography showed bilateral diffuse infiltrates. After supportive measures were taken, complete respiratory recovery occurred in 72 hours. A 52-year-old woman had several seizure episodes following subarachnoid hemorrhage due to a cavernoma. She became increasingly dyspneic upon arrival at the hospital. After tracheostomy and oxygen support were established, chest radiography showed bilateral diffuse infiltrates. Respiratory recovery was excellent, and the patient was eupneic with normal results of chest radiography 48 hours later. Fourteen reports (21 cases) were found. Thirteen patients were female, and the mean age of the patients was 31.6 years. The most frequent underlying factor was subarachnoid hemorrhage (42.9%). Symptom onset occurred <4 hours after the neurologic event in 71.4% of cases. One third of the patients presented with pink frothy sputum. Chest radiography showed bilateral diffuse infiltrates in 90.5% of cases. Supportive measures included oxygen support and vasoactive drugs. Recovery was usually very rapid: 52.4% of patients recovered in <72 hours. Almost 10% of patients died of NPE. Our two cases had clinical and laboratory features in common with most NPE cases. Physicians should remember NPE when neurologic patients suddenly become dyspneic. The mortality rate is high, but surviving patients usually recover very quickly.

Cell-based in vitro models for predicting drug permeability

INTRODUCTION

In vitro cell models have been used to predict drug permeation in early stages of drug development, since they represent an easy and reproducible method, allowing the tracking of drug absorption rate and mechanism, with an advantageous cost-benefit ratio. Such cell-based models are mainly composed of immortalized cells with an intrinsic ability to grow in a monolayer when seeded in permeable supports, maintaining their physiologic characteristics regarding epithelium cell physiology and functionality.

AREAS COVERED

This review summarizes the most important intestinal, pulmonary, nasal, vaginal, rectal, ocular and skin cell-based in vitro models for predicting the permeability of drugs. Moreover, the similitude between in vitro cell models and in vivo conditions are discussed, providing evidence that each model may provisionally resemble different drug absorption route.

EXPERT OPINION

Despite the widespread use of in vitro cell models for drug permeability and absorption evaluation purposes, a detailed study on the properties of these models and their in vitro-in vivo correlation compared with human data are required to further use in order to consider a future drug discovery optimization and clinical development.

Apoptosis in systemic lupus erythematosus. Clinical implications

SLE is a heterogeneous and complex group of disorders of uncertain cause. Recent studies have suggested that abnormalities in the apoptotic cell death process may play an important role in the initiation and propagation of this spectrum of disease by altering the generation and cleavage of antigens, and through abnormalities in immunoregulation. The clustering and concentration of autoantigens in and on the surface blebs of apoptotic cells, modifications of antigen structure during certain forms of apoptotic death, and abnormalities in apoptotic cell clearance in humans with SLE and in certain animal models are reviewed and synthesized into a comprehensive model of systemic autoimmunity.

Stimuli-Responsive Hydrogels for Cancer Treatment: The Role of pH, Light, Ionic Strength and Magnetic Field

Cancer remains as the second leading cause of death, worldwide. Despite the enormous important advances observed in the last decades, advanced stages of the disease remain incurable. The severe side effects associated to systemic high doses of chemotherapy and the development of drug resistance impairs a safe and efficiency anticancer therapy. Therefore, new formulations are continuously under research and development to improve anticancer drugs therapeutic index through localized delivery at tumor sites. Among a wide range of possibilities, hydrogels have recently gained special attention due to their potential to allow in situ sustained and controlled anticancer drug release. In particular, stimuli-responsive hydrogels which are able to change their physical state from liquid to gel accordingly to external factors such as temperature, pH, light, ionic strength, and magnetic field, among others. Some of these formulations presented promising results for the localized control and treatment of cancer. The present work aims to discuss the main properties and application of stimuli-responsive hydrogels in cancer treatment and summarize the most important advances observed in the last decades focusing on the use of pH-, light-, ionic strength-, and magnetic-responsive hydrogels.

Adenovirus L4-100K assembly protein is a granzyme B substrate that potently inhibits granzyme B-mediated cell death

Cytotoxic lymphocytes kill virus-infected target cells and play a critical role in host recovery from viral infections. Granzyme B (GrB) is a cytotoxic lymphocyte granule protease that plays a critical role in mediating cytotoxicity. In these studies, we demonstrate that the adenovirus assembly protein L4--100K (100K) is a GrB substrate that prevents cytotoxic lymphocyte granule-induced apoptosis in infected target cells by potently inhibiting GrB. This inhibition is absolutely dependent on Asp-48 in 100K, found within a classic GrB consensus motif. 100K is the first viral protein described that exclusively targets the GrB pathway. It represents a novel class of viral protease inhibitor, in which an essential, multifunctional viral protein, which is vulnerable to specific proteolysis by GrB, expresses inhibitory function against that protease.

Design of a nanostructured lipid carrier intended to improve the treatment of tuberculosis

This work aimed to design, develop, and characterize a lipid nanocarrier system for the selective delivery of rifabutin (RFB) to alveolar macrophages. Lipid nanoparticles, specifically nanostructured lipid carriers (NLC), were synthetized by the high-shear homogenization and ultrasonication techniques. These nanoparticles were designed to exhibit both passive and active targeting strategies to be efficiently internalized by the alveolar macrophages, traffic to the acidified phagosomes and phagolysosomes, and release bactericidal concentrations of the antituberculosis drug intracellularly. NLC that could entrap RFB were prepared, characterized, and further functionalized with mannose. Particles’ diameter, zeta potential, morphology, drug% entrapping efficiency, and drug release kinetics were evaluated. The mannose coating process was confirmed by Fourier transform infrared. Further, the cytotoxicity of the formulations was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay in A549, Calu-3, and Raw 264.7 cells. The diameter of NLC formulations was found to be in the range of 175–213 nm, and drug entrapping efficiency was found to be above 80%. In addition, high storage stability for the formulations was expected since they maintained the initial characteristics for 6 months. Moreover, the drug release was pH-sensitive, with a faster drug release at acidic pH than at neutral pH. These results pose a strong argument that the developed nanocarrier can be explored as a promising carrier for safer and more efficient management of tuberculosis by exploiting the pulmonary route of administration.

Nanocarriers for pulmonary administration of peptides and therapeutic proteins

Peptides and therapeutic proteins have been the target of intense research and development in recent years by the pharmaceutical and biotechnology industry. Preferably, they are administered through the parenteral route, which is associated with reduced patient compliance. Formulations for noninvasive administration of peptides and therapeutic proteins are currently being developed. Among them, inhalation appears as a promising alternative for the administration of such products. Several formulations for pulmonary delivery are in various stages of development. Despite positive results, conventional formulations have some limitations such as reduced bioavailability and side effects. Nanocarriers may be an alternative way to overcome the problems of conventional formulations. Some nanocarrier-based formulations of peptides and therapeutic proteins are currently under development. The results obtained are promising, revealing the usefulness of these systems in the delivery of such drugs.

Non-apoptotic functions of granzymes

Granzymes (granule enzymes) are proteases released from cytotoxic lymphocyte granules into target cells to protect mammals from virus infection and transformed cells. Once released into the cytoplasm of the target cell, granzymes activate specific pathways to induce cell death. Although the induction of target cell death has been considered the central function for these proteases, accumulating evidence suggests that granzymes also possess additional non-death-related functions. Thus, some granzymes can achieve direct antiviral activities through the cleavage of proteins encoded by viruses as well as host factors required for the viral life cycle. The presence of elevated concentrations of circulating granzymes in various inflammatory processes and granzyme-mediated cleavage of extracellular substrates suggest that these proteases may have extracellular effects relevant to virus and tumor rejection and the pathogenesis of chronic inflammatory diseases. Here, we discuss the current knowledge of the substrates and the proposed non-apoptotic functions of granzymes, with special interest in non-death-related functions of granzymes inside the target cell.

Cleavage of La protein by granzyme H induces cytoplasmic translocation and interferes with La-mediated HCV-IRES translational activity

Granzymes are key components of the cytotoxic arm of the immune response, which play critical roles in eliminating host cells infected by intracellular pathogens and transformed cells. Although the induction of cell death is likely a central process underlying the function of these enzymes, little is known about whether granzymes use additional mechanisms to exert their antipathogen activity. This study identifies La, a phosphoprotein involved in multiple roles in cellular and viral RNA metabolism, as the first nonapoptotic substrate of granzyme H (gzmH), a cytotoxic granule protease that is constitutively expressed by NK cells. Cleavage of La by gzmH occurs at Phe-364 (P(1) site) and generates a COOH-terminal truncated form of La that loses nuclear localization and decreases HCV (hepatitis C virus)-internal ribosome entry site (IRES)-mediated translational activity. The ability of gzmH to cleave host proteins involved in essential viral functions provides a novel mechanism by which granzymes can mediate direct antiviral activities.

Relationship of anticardiolipin antibodies and antiphospholipid syndrome to HLA-DR7 in Mexican patients with systemic lupus erythematosus (SLE)

We studied IgG and IgM anticardiolipin antibodies (aCL) by an ELISA method in 80 Mexican systemic lupus erythematosus (SLE) patients and 378 of their first degree relatives. Sixty five percent of SLE patients and 16% of their relatives were positive for aCL. We also determined allele and haplotype frequencies of Major Histocompatibility Complex (MHC) genes (classes I, II and III) in both patients and relatives. MHC allele and haplotype frequencies of aCL positive and negative individuals were compared to those of normal ethnically matched controls. SLE patients with aCL had statistically significant increased corrected frequencies of HLA-DR3 (pC = 0.04, RR = 2.78); DR7 (pC = 0.005), RR = 3.42) and DQ2 (pC = 0.003, RR = 2.58) antigens. Their first degree relatives positive for aCL also had increased frequency of HLA-DR7 but it did not remain significant after correcting the P value. On the other hand, SLE patients negative for aCL had a moderate increased frequency of DR3 and DQ2 but not of DR7. These results suggest that DR7 associates with the presence of aCL. The distribution of MHC alleles in SLE patients positive for aCL resembles that found in their aCL positive first degree relatives. Since the presence of the antibody is not sufficient to predict a clinical outcome, we studied those patients with reliable clinical data regarding the presence of the antiphospholipid syndrome (aPLS). SLE patients with aPLS had significantly increased frequency of DR7 (pC = 0.004), as did those with probable aPLS (pC = 0.05), while the frequency of DR7 in SLE patients in the doubtful or negative aPLS categories was no different from normal controls. These data support a possible role of DR7 in the development of aCL in SLE patients and their relatives and suggest a contribution of this class II MHC antigen to the development of aPLS within SLE.

Chitosan formulations as carriers for therapeutic proteins

Protein drugs represent a significant part of the new pharmaceuticals coming on the market every year and are now widely spread in therapy to treat or relief symptomatology related to many metabolic and oncologic diseases. The delivery of therapeutic proteins is still a major drawback against their maximum pharmacodynamic due to their physicochemical properties, poor stability, permeability and biodistribution. Despite the fact that the parenteral route remains the primary route of protein administration, research continues on non-parenteral delivery routes. However, the high molecular weight of proteins, combined with their hydrophilic and charged nature, renders transport through membranes very difficult. In this regard, the biopolymer chitosan exhibits several favorable biological properties, such as biocompatibility, biodegradability, low-toxicity and mucoadhesiveness, which made it a promising candidate for the formulation of protein drugs. The success of a protein formulation depends not only on the stability of the delivery system but also on their ability to maintain the native structure and activity of the protein during preparation and the delivery, as well as during long-term storage of the formulation. Chitosan-based delivery systems have been proposed as valid approaches to provide such protective conditions. The development of novel protein delivery systems based on chitosan is a rising subject irrespective of the intended route of administration. In this review, the different approaches recently exploited to formulate and deliver therapeutic proteins are underlined.

The role of HLA-DR alleles and complotypes through the ethnic barrier in systemic lupus erythematosus in Mexicans

Alleles of the major histocompatibility complex (MHC) have been recognized as genetic factors for the development of SLE. The [HLA-B8; SC01; DR3] extended haplotype seems to be relevant in patients from white European descent, pertinent alleles, however, are difficult to select on haplotypes with linkage disequilibrium. Studies in non-Caucasian patients are therefore mandatory. Admixture estimates in Mexicans have shown a proportion of 56% of Indian genes, 40% of Caucasian genes and from 4 to 12% of Black genes. In order to determine the relevant MHC loci in the genetic susceptibility for SLE we studied Class I, II and III alleles in 102 Mexican SLE patients and 350 of their first degree relatives and compared these two groups to another one composed by 200 ethnically matched normal individuals. We found significantly increased frequencies of HLA-DR3 (pC = 0.03, RR = 2.56) and DR7 (pC = 0.004, RR = 3.08) in SLE patients as compared to controls. On the other hand, first degree relatives had a significantly increased frequency of HLA-DR7 (pC = 0.01, RR = 2.98). There were 21 out of 33 HLA-DR3 haplotypes with complotypes other than SC01 and 25 out 37 SC01 haplotypes with DR alleles other than DR3. Nevertheless, [SC01; DR3] haplotypes were also increased (pC = 0.01, RR = 12.4). After removing [HLA-B8; SC01; DR3] haplotypes, DR3 was the only allele that remained significantly increased (p = 0.04, RR = 2.1). We also found in SLE patients significantly decreased frequencies of the autochthonous Mexican alleles (A30, B39 and DR4) and no deviation from normality of any of the HLA-DQ alleles. These data suggest a fundamental role of the HLA-DR3 allele in the predisposition to SLE in Mexican patients which might be hightened by genes located around the class III MHC region. They also substantiate the pertinence of ethnic admixture estimates in modern human populations.

Thermo-responsive hydrogels for cancer local therapy: Challenges and state-of-art

Despite the enormous efforts done by the scientific community in the last decades, advanced cancer is still considered an incurable disease. New formulations are continuously under investigation to improve drugs therapeutic index, i.e., increase chemotherapeutic efficacy and reduce adverse effects. In this context, hydrogels-based systems for drug local sustained/controlled release have been proposed to reduce off-target effects caused by the repeated administration of systemic/oral anticancer drugs and improve their therapeutic effectiveness. Moreover, it increases the patient welfare by reducing the number of administrations needed. Among the several types of existing hydrogels, the thermo-responsive ones, which are able to change their physical state from liquid at 25 °C to a gel at the body temperature, i.e., 37 °C, gained special attention as in situ sustained drug release depot-systems in cancer treatment. To date, several thermo-responsive hydrogels have been used for drugs and/or genetic material delivery, yielding promising results both at preclinical and clinical evaluation stages. This culminates in the market authorization of Jelmyto® for the treatment of urothelial cancer. Here are summarized and discussed the last 10 years advances regarding the application of thermo-responsive hydrogels in local cancer treatment.

Polymeric micelles targeted against CD44v6 receptor increase niclosamide efficacy against colorectal cancer stem cells and reduce circulating tumor cells in vivo

Colorectal cancer (CRC) is a highly prevalent disease worldwide. Patient survival is hampered by tumor relapse and the appearance of drug-resistant metastases, which are sustained by the presence of cancer stem cells (CSC). Specific delivery of anti-CSC chemotherapeutic drugs to tumors by using targeted drug delivery systems that can also target CSC sub-population might substantially improve current clinical outcomes. CD44v6 is a robust biomarker for advanced CRC and CSC, due to its functional role in tumorigenesis and cancer initiation process. Here, we show that CD44v6-targeted polymeric micelles (PM) loaded with niclosamide (NCS), a drug against CSC, is a good therapeutic strategy against colorectal CSC and circulating tumor cells (CTC) in vivo. HCT116 cells were sorted according to their CD44v6 receptor expression into CD44v6+ (high) and CDv44v6- (low) subpopulations. Accordingly, CD44v6+ cells presented stemness properties, such as overexpression of defined stemness markers (ALDH1A1, CD44v3 and CXCR4) and high capacity to form colonspheres in low attachment conditions. NCS-loaded PM functionalized with an antibody fragment against CD44v6 (Fab-CD44v6) presented adequate size, charge, and encapsulation efficiency. In addition, Fab-CD44v6 significantly increased PM internalization in CD44v6+ cells. Further, encapsulation of NCS improved its effectiveness in vitro, particularly against colonspheres, and allowed to increase its intravenous dosage in vivo by increasing the amount of NCS able to be administered without causing toxicity. Remarkably, functionalized PM accumulate in tumors and significantly reduce CTC in vivo. In conclusion, CD44v6 targeted PM meet the essential conditions to become an efficient anti-CSC therapy.