The protective role of CD73 in periodontitis: preventing hyper-inflammatory fibroblasts and driving osteoclast energy metabolism.

Introduction: Periodontitis is an immune-mediated inflammatory disease affecting almost half of the adult population and is the leading cause of tooth loss in the United States. The role of extracellular nucleotide signaling including nucleotide metabolizing enzyme CD73 adds an important layer of interaction of purine mediators capable of orchestrating inflammatory outcomes. CD73 is able to catabolize 5'-adenosine monophosphate into adenosine at the extracellular level, playing a critical role in regulating many processes under physiological and pathological conditions. Here, we explored the role of CD73 in ligature-induced periodontitis in vivo comparing wild-type C57Bl/6J and CD73-deficient mice. Methods: We assessed gingival levels of inflammatory cytokines in vivo and in murine gingival fibroblasts in vitro, as well as bone loss, and RANKL-induced osteoclastogenesis. We have also analyzed CD73 mRNA in samples derived from patients diagnosed with severe periodontitis. Results: Our results in mice show that lack of CD73 resulted in increased inflammatory cytokines and chemokines such as IL-1ß, IL-17, Cxcl1 and Cxcl2 in diseased gingiva relative to the healthy-controls and in comparison with the wild type. CD73-deficient gingival fibroblasts also manifested a defective healing response with higher MMP-13 levels. CD73-deficient animals also showed increased osteoclastogenesis in vitro with increased mitochondrial metabolism typified by excessive activation of oxidative phosphorylation, increased mitochondrial membrane potential and accumulation of hydrogen peroxide. Micro-CT analysis revealed that lack of CD73 resulted in decreased bone mineral density, decreased trabecular bone volume and thickness as well as decreased bone volume in long bones. CD73 deficiency also resulted in increased alveolar bone loss in experimental periodontitis. Correlative studies of gingival samples from severe (Grade C) periodontitis showed decreased levels of CD73 compared to healthy controls, further supporting the relevance of our murine results. Conclusion: In conclusion, CD73 appears to play a protective role in the gingival periodontal tissue and bone homeostasis, regulating hyper-inflammatory state of stromal fibroblasts and osteoclast energy metabolism and being an important candidate for future target therapies to prevent or control immune-mediated inflammatory and osteolytic diseases.

A synthetic biology approach to engineering circuits in immune cells.

A synthetic circuit in a biological system involves the designed assembly of genetic elements, biomolecules, or cells to create a defined function. These circuits are central in synthetic biology, enabling the reprogramming of cellular behavior and the engineering of cells with customized responses. In cancer therapeutics, engineering T cells with circuits have the potential to overcome the challenges of current approaches, for example, by allowing specific recognition and killing of cancer cells. Recent advances also facilitate engineering integrated circuits for the controlled release of therapeutic molecules at specified locations, for example, in a solid tumor. In this review, we discuss recent strategies and applications of synthetic receptor circuits aimed at enhancing immune cell functions for cancer immunotherapy. We begin by introducing the concept of circuits in networks at the molecular and cellular scales and provide an analysis of the development and implementation of several synthetic circuits in T cells that have the goal to overcome current challenges in cancer immunotherapy. These include specific targeting of cancer cells, increased T-cell proliferation, and persistence in the tumor microenvironment. By harnessing the power of synthetic biology, and the characteristics of certain circuit architectures, it is now possible to engineer a new generation of immune cells that recognize cancer cells, while minimizing off-target toxicities. We specifically discuss T-cell circuits for antigen density sensing. These circuits allow targeting of solid tumors that share antigens with normal tissues. Additionally, we explore designs for synthetic circuits that could control T-cell differentiation or T-cell fate as well as the concept of synthetic multicellular circuits that leverage cellular communication and division of labor to achieve improved therapeutic efficacy. As our understanding of cell biology expands and novel tools for genome, protein, and cell engineering are developed, we anticipate further innovative approaches to emerge in the design and engineering of circuits in immune cells.

Fibroblasts at the curtain call: from ensemble to principal dancers in immunometabolism and inflammaging.

Inflammation is a necessary step in response to injuries, being vital in restoring homeostasis and facilitating tissue healing. Among the cells that play a crucial role in inflammatory responses, stromal cells, including fibroblasts, have an undeniable significance in fine-tuning the magnitude of mediators that directly affect hyper-inflammatory responses and tissue destruction. Fibroblasts, the dominant cells in the gingival connective tissue, are a very heterogeneous population of cells, and more recently they have been receiving well deserved attention as central players and often the 'principal dancers' of many pathological processes ranging from inflammation and fibrosis to altered immunity and cancer. The goal of the current investigation is to dive into the exact role of the stromal fibroblast and the responsible mechanistic factors involved in both regulation and dysregulation of the inflammatory responses. This article reviews the most recent literature on how fibroblasts, in their different activation states or subtypes, play a crucial role in contributing to inflammatory outcomes. We will focus on recent findings on inflammatory diseases. We will also provide connections regarding the stromal-immune relationship, which supports the idea of fibroblast coming out from the 'ensemble' of cell types to the protagonist role in immunometabolism and inflammaging. Additionally, we discuss the current advances in variation of fibroblast nomenclature and division into clusters with their own suggested function and particularities in gene expression. Here, we provide a perspective for the periodontal implications, discussing the fibroblast role in the infection-driven and inflammatory mediated diseases such as periodontitis.

Metabolic reprogramming through mitochondrial biogenesis drives adenosine anti-inflammatory effects: new mechanism controlling gingival fibroblast hyper-inflammatory state.

Introduction: Fibroblasts are the dominant stromal cells in the gingival lamina propria with a well-established relevance in regulation of inflammation, and in innate immunity. This is exemplified by their hypersecretion of CXCL8, enhancing leukocyte infiltration in chronic and sustained inflammatory conditions. We have previously shown adenosine to be a key metabolic nucleoside that regulates stromal inflammation, but the underlying mechanisms linking adenosine to the metabolic status of fibroblasts and to the resultant inflammatory response are unclear. This study examined, by seahorse real-time cell metabolic analysis, the bioenergetics of the stromal fibroblast response to extracellular adenosine and IL-1ß, focusing on CXCL8 secretion by primary human gingival fibroblasts (HGF). Methods: Markers of the glycolytic pathway and mitochondrial biogenesis were tracked through immunoblot. Further, the influence of adenosine on mitochondrial accumulation was measured by uptake of MitoTracker Red fluorescent probe and assessment of the role of FCCP (a mitochondrial uncoupler) in CXCL8 secretion and mitochondrial accumulation. Results: Our results show that the anti-inflammatory response of HGF to extracellular adenosine, typified by reduced CXCL8 secretion, is mediated by mitochondrial oxidative phosphorylation, reflected in higher oxygen consumption rate (OCR). In the presence of IL-1ß, adenosine-treated cells induced higher ATP production, basal respiration and proton leak compared to IL-1ß without adenosine. Surprisingly, adenosine had no additional effect on the IL-1ß-induced higher glycolysis rate demonstrated by the extracellular acidification rate (ECAR). In addition, the higher OCR in adenosine-stimulated cells was not due to the mitochondrial fuel dependency or capacity, but due to an increase in mitochondrial biogenesis and accumulation in the cells with concomitant decrease in mitophagy-required p-PINK1 marker. We detected the accumulation of functional mitochondria with increased activation of the AMPK/SIRT1/PGC-1α pathway. The adenosine-induced uptake of MitoTracker was abrogated by PGC-1α inhibition with SR-12898. In addition, the adenosine effects on reduced CXCL8 were ablated by treatment with FCCP, a potent uncoupler of mitochondrial oxidative phosphorylation. Conclusion: Our findings reveal a key role for mitochondrial bioenergetics in regulation of CXCL8-mediated inflammation by HGF through the adenosine/AMPK/SIRT1/PGC-1α axis. Therapeutically targeting this pathway in gingival fibroblasts might be a promising future strategy to modulate stromal-mediated sustained hyper-inflammatory responses.

Fibroblasts at the curtain call: from ensemble to principal dancers in immunometabolism and inflammaging

Abstract Inflammation is a necessary step in response to injuries, being vital in restoring homeostasis and facilitating tissue healing. Among the cells that play a crucial role in inflammatory responses, stromal cells, including fibroblasts, have an undeniable significance in fine-tuning the magnitude of mediators that directly affect hyper-inflammatory responses and tissue destruction. Fibroblasts, the dominant cells in the gingival connective tissue, are a very heterogeneous population of cells, and more recently they have been receiving well deserved attention as central players and often the 'principal dancers' of many pathological processes ranging from inflammation and fibrosis to altered immunity and cancer. The goal of the current investigation is to dive into the exact role of the stromal fibroblast and the responsible mechanistic factors involved in both regulation and dysregulation of the inflammatory responses. This article reviews the most recent literature on how fibroblasts, in their different activation states or subtypes, play a crucial role in contributing to inflammatory outcomes. We will focus on recent findings on inflammatory diseases. We will also provide connections regarding the stromal-immune relationship, which supports the idea of fibroblast coming out from the 'ensemble' of cell types to the protagonist role in immunometabolism and inflammaging. Additionally, we discuss the current advances in variation of fibroblast nomenclature and division into clusters with their own suggested function and particularities in gene expression. Here, we provide a perspective for the periodontal implications, discussing the fibroblast role in the infection-driven and inflammatory mediated diseases such as periodontitis.

Primary hepatic gastrinoma, extremely rare case presentation and its surgical resolution, in a third level hospital in Mexico.

The gastrinomas are rare functional neuroendocrine neoplasms, most are localized to the duodenum (70-90%) or the pancreas (2-30%), but less common ectopic sites have been reported. The primary hepatic gastrinoma is extremely rare, with less tan 40 cases reported in the medical literature. Its low incidence and its non specific clinical presentation make it a difficult disease to diagnose. Providing a timely diagnosis the patient can be treated by surgical resection with high chances of success. The objective of this paper is to describe a case of primary hepatic gastrinoma in Mexico, successfully treated by right liver segmentectomy.

Los gastrinomas son neoplasias neuroendocrinas funcionales raras, y la mayoría se localizan en el duodeno (70-90%) o en el páncreas (2-30%), pero también existen otras localizaciones ectópicas poco comunes. El gastrinoma hepático primario es extremadamente raro, con menos de 40 casos reportados en la literatura médica. Su baja incidencia y su presentación clínica inespecífica lo convierten en una enfermedad difícil de diagnosticar. Al realizar un diagnóstico oportuno puede ser tratado mediante resección quirúrgica con altas posibilidades de éxito. El objetivo de este trabajo es presentar un caso clínico de gastrinoma hepático primario en México, tratado de manera exitosa mediante segmentectomía hepática derecha.

Synthetic biology: at the crossroads of genetic engineering and human therapeutics-a Keystone Symposia report.

Synthetic biology has the potential to transform cell- and gene-based therapies for a variety of diseases. Sophisticated tools are now available for both eukaryotic and prokaryotic cells to engineer cells to selectively achieve therapeutic effects in response to one or more disease-related signals, thus sparing healthy tissue from potentially cytotoxic effects. This report summarizes the Keystone eSymposium "Synthetic Biology: At the Crossroads of Genetic Engineering and Human Therapeutics," which took place on May 3 and 4, 2021. Given that several therapies engineered using synthetic biology have entered clinical trials, there was a clear need for a synthetic biology symposium that emphasizes the therapeutic applications of synthetic biology as opposed to the technical aspects. Presenters discussed the use of synthetic biology to improve T cell, gene, and viral therapies, to engineer probiotics, and to expand upon existing modalities and functions of cell-based therapies.

The role of sex and gender in the selection of Alzheimer patients for clinical trial pre-screening.

BACKGROUND: Alzheimer disease (AD) is a progressive neurodegenerative disorder affecting the elderly with a prevalence of 7.1% in women and 3.3% in men. Sex-related patterns have been reported in prognosis, biomarker status, and risk factors. Despite this, the interaction of sex has received limited attention, with AD trials persistently recruiting lower numbers of women than the population distribution and a lack of information on the sex-disaggregated effects of anti-dementia therapies. This is the first study aiming to identify the role of sex in the selection for screening in AD clinical trials. METHODS: This cross-sectional study provides a comprehensive analysis of screening eligibility according to a set of pre-selection criteria currently applied at Fundació ACE memory clinic for a more efficient trial screening process. A cohort of 6667 women and 2926 men diagnosed with AD dementia (55%) or mild cognitive impairment (45%) was analyzed. We also assessed the frequencies of men and women effectively screened for trial enrolment over a period of 10 years. Additionally, data from AddNeuroMed study was used to explore trends in eligibility based on the education criteria. RESULTS: Women showed a significantly lower chance of being eligible for screening than men (OR = 1.26; p < 0.01). This imbalance was confirmed by a lower frequency of women screened for enrolment compared to the study population (63.0% vs. 69.5%). Education was revealed as the key criterion contributing to this unbalance, with men showing over twice the chance of being screened compared with women (OR = 2.25, p < 0.01). Education-based differences were greater in earlier born patients, but the gap narrowed and achieved balance with increasing year of birth. This observation was replicated using data from other European populations included in AddNeuroMed study. Comorbidity was the most limiting criterion with sex differences in frequencies and significant discrimination against the selection of men (OR = 0.86, p < 0.01). CONCLUSIONS: The large number of low-educated elderly women with AD demands for a sex-focused approach in clinical research. New assessment tools insensitive to education level should be developed to enable a proportional representation of women. Although this gender education gap is mostly inexistent in developed countries, economic or cultural factors may lead to different scenarios in other regions. Overlooking the impact of sex may lead to a handicap in AD research with a direct adverse impact on women's health.

T cell circuits that sense antigen density with an ultrasensitive threshold.

Overexpressed tumor-associated antigens [for example, epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2)] are attractive targets for therapeutic T cells, but toxic "off-tumor" cross-reaction with normal tissues that express low levels of target antigen can occur with chimeric antigen receptor (CAR)-T cells. Inspired by natural ultrasensitive response circuits, we engineered a two-step positive-feedback circuit that allows human cytotoxic T cells to discriminate targets on the basis of a sigmoidal antigen-density threshold. In this circuit, a low-affinity synthetic Notch receptor for HER2 controls the expression of a high-affinity CAR for HER2. Increasing HER2 density thus has cooperative effects on T cells-it increases both CAR expression and activation-leading to a sigmoidal response. T cells with this circuit show sharp discrimination between target cells expressing normal amounts of HER2 and cancer cells expressing 100 times as much HER2, both in vitro and in vivo.

DNA scaffolds enable efficient and tunable functionalization of biomaterials for immune cell modulation.

Biomaterials can improve the safety and presentation of therapeutic agents for effective immunotherapy, and a high level of control over surface functionalization is essential for immune cell modulation. Here, we developed biocompatible immune cell-engaging particles (ICEp) that use synthetic short DNA as scaffolds for efficient and tunable protein loading. To improve the safety of chimeric antigen receptor (CAR) T cell therapies, micrometre-sized ICEp were injected intratumorally to present a priming signal for systemically administered AND-gate CAR-T cells. Locally retained ICEp presenting a high density of priming antigens activated CAR T cells, driving local tumour clearance while sparing uninjected tumours in immunodeficient mice. The ratiometric control of costimulatory ligands (anti-CD3 and anti-CD28 antibodies) and the surface presentation of a cytokine (IL-2) on ICEp were shown to substantially impact human primary T cell activation phenotypes. This modular and versatile biomaterial functionalization platform can provide new opportunities for immunotherapies.

Dementia Care in Times of COVID-19: Experience at Fundació ACE in Barcelona, Spain.

BACKGROUND: Fundació ACE is a non-profit organization providing care based on a holistic model to persons with cognitive disorders and their families for 25 years in Barcelona, Spain. Delivering care to this vulnerable population amidst the COVID-19 pandemic has represented a major challenge to our institution. OBJECTIVE: To share our experience in adapting our model of care to the new situation to ensure continuity of care. METHODS: We detail the sequence of events and the actions taken within Fundació ACE to swiftly adapt our face-to-face model of care to one based on telemedicine consultations. We characterize individuals under follow-up by the Memory Unit from 2017 to 2019 and compare the number of weekly visits in 2020 performed before and after the lockdown was imposed. RESULTS: The total number of individuals being actively followed by Fundació ACE Memory Unit grew from 6,928 in 2017 to 8,147 in 2019. Among those newly diagnosed in 2019, most patients had mild cognitive impairment or mild dementia (42% and 25%, respectively). Weekly visits dropped by 60% following the suspension of face-to-face activity. However, by April 24 we were able to perform 78% of the visits we averaged in the weeks before confinement began. DISCUSSION: We have shown that Fundació ACE model of care has been able to successfully adapt to a health and social critical situation as COVID-19 pandemic. Overall, we were able to guarantee the continuity of care while preserving the safety of patients, families, and professionals. We also seized the opportunity to improve our model of care.

Expression of Cytokines Interleukin-2, Interleukin-4, Interleukin-10 and Transforming Growth Factor ß in Gastric Adenocarcinoma Biopsies Obtained from Mexican Patients

Objective: In this study, expression of Interleukin-2, Interleukin-4, Interleukin-10 and transforming growth factor beta in diffuse and intestinal type gastric cancers from Mexican patients was assessed for use as markers of malignancy. Methods: A total of 30 biopsies from gastric adenocarcinomas, 60% diffuse, 20% intestinal and 20% mixed in type, were studied by immunohistochemistry. Results: Regarding expression of cytokines, 23% were positive for IL-2, 26.7% for IL-4, 16.6% for IL-10 and none for TGF-ß. There were found Significant statistically stage differences were noted.For example, for stages I-II 100% were IL-2 positive (p = 0.009), 87.5% were IL-4 positive (p = 0.005) and 100.0% IL-10 positive (p = 0.009). Young women were more likely to suffer gastric adenocarcinoma. In biopsies of male patients with gastric cancer, there was an increased expression of IL-2 and in biopsies from female patients in IL4. There was significantly greater detection of IL-4 and IL-10 expression in stages I and II than in stages III and IV. It was also found that IL-4, IL-10 had a higher positive expression in patients biopsies with low-level differentiations than patients with well differentiated gastric cancer in which cases were undetected. Conclusions: These results suggest that positive expression of IL-4 and IL-10 may be useful as a molecular marker to distinguish stage I and II diffuse gastric cancers which can be more readily controlled.

[Surgical treatment for liver haematoma following endoscopic retrograde cholangiopancreatography; An unusual case]. / Tratamiento quirúrgico para hematoma subcapsular hepático posterior a colangiografía retrógrada endoscópica; caso inusual.

BACKGROUND: Even in expert hands, there can be serious complications when performing an endoscopic retrograde cholangiopancreatography. The most frequent complications are pancreatitis, cholangitis, bleeding, perforation, and acute cholecystitis. The hepatic subcapsular haematoma is a rare complication, with few cases described worldwide. OBJECTIVE: A case is presented of an extremely rare complication of endoscopic retrograde cholangiopancreatography, which required surgical treatment for its resolution without success. This is second case of mortality reported in the literature. CLINICAL CASE: Female patient of 30 years old, with indication for endoscopic retrograde cholangiopancreatography due to benign strictures. A hydro-pneumatic dilation and stent placement of 2 gauge 10 fr was performed. She presented abdominal pain after the procedure and significant decline in haemoglobin with no evidence of haemodynamic instability so an abdominal tomography scan was performed, showing no evidence of liver injury. The patient was haemodynamic unstable within 72 h. A laparotomy was required for damage control, with fatal outcome in the intensive care unit due to multiple organ failure. CONCLUSION: Subcapsular hepatic haematoma after endoscopic retrograde cholangiopancreatography is a rare complication, with few cases reported in the literature. Treatment described in the literature is conservative, resulting in a satisfactory resolution.

A systematic comparison of mathematical models for inherent measurement of ciliary length: how a cell can measure length and volume.

Cells control organelle size with great precision and accuracy to maintain optimal physiology, but the mechanisms by which they do so are largely unknown. Cilia and flagella are simple organelles in which a single measurement, length, can represent size. Maintenance of flagellar length requires an active transport process known as intraflagellar transport, and previous measurements suggest that a length-dependent feedback regulates intraflagellar transport. But the question remains: how is a length-dependent signal produced to regulate intraflagellar transport appropriately? Several conceptual models have been suggested, but testing these models quantitatively requires that they be cast in mathematical form. Here, we derive a set of mathematical models that represent the main broad classes of hypothetical size-control mechanisms currently under consideration. We use these models to predict the relation between length and intraflagellar transport, and then compare the predicted relations for each model with experimental data. We find that three models-an initial bolus formation model, an ion current model, and a diffusion-based model-show particularly good agreement with available experimental data. The initial bolus and ion current models give mathematically equivalent predictions for length control, but fluorescence recovery after photobleaching experiments rule out the initial bolus model, suggesting that either the ion current model or a diffusion-based model is more likely correct. The general biophysical principles of the ion current and diffusion-based models presented here to measure cilia and flagellar length can be generalized to measure any membrane-bound organelle volume, such as the nucleus and endoplasmic reticulum.

[Levonorgestrel intrauterine device associated with ureterpyelocaliceal ectasia]. / Dispositivo intrauterino con levonorgestrel translocado asociado con ectasia ureteropielocalicial bilateral.

BACKGROUND: In 2010, Health Canada, the equivalent to the FDA, reported that the risk of uterine perforation caused by levonorgestrel intrauterine device (IUD) is very serious, warning that its use had increased the number of uterine perforation. CLINICAL CASE: A 33 years old patient in who was placed three years before a levonorgestrel IUD; She presented evolution of 10 days with pain in hypogastric and both flanks and chronic constipation of two years; in exploration: moderate abdominal distention, IUD strings were not visible in uterine cervix. With translocated IUD diagnosis, a tomography was performed, finding IUD in abdominal cavity and ureter pyelocalyceal bilateral ectasia; preoperative plasma concentration of levonorgestrel 5.1 nmol/L, leukocytosis of 11,000 cells/mm3, and 20-30 erythrocytes in urine exam. Laparoscopic resection of omentum attached to IUD translocated was performed. One month after surgery plasma levonorgestrel in 0.3 nmol/L, normal urinalysis and hematic cytometry and resolution of the urinary tract ectasia. CONCLUSIONS: devices translocated with levonorgestrel, must be removed because the inflammatory reaction caused and the perforation of hollow viscera likelihood, with possibility to produce digestive tract and urinary tract ectasia by its pharmacologic action on smooth muscle.

[Relationship between dyslipidemia and severity in preeclampsia]. / Relación de dislipidemias y gravedad en preeclampsia.

BACKGROUND: It has been found that the cholesterol and triglyceride values are higher in preeclampsia than in normal pregnancy, even though it is unclear whether these levels are related to the severity. The aim of this study was to determine the correlation between dyslipidemia and severity in preeclampsia. METHODS: Comparative cross-sectional study in 200 patients, 100 with normal pregnancy and 100 with preeclampsia. The age, gynecological and obstetric history, total cholesterol and triglycerides were identified. Descriptive statistics were used: Student's t test for comparing the group of patients with preeclampsia and normal pregnancies, and ANOVA and odds ratio for the subanalysis of mild and severe preeclampsia. RESULTS: No statistically significant differences in age or cholesterol were found. Triglycerides showed a statistically significant difference: they were higher in relation to the severity of preeclampsia (normal pregnancy: 245 mg; mild preeclampsia: 308 mg; severe preeclampsia: 349 mg). CONCLUSIONS: Elevated levels of cholesterol and triglycerides in patients with preeclampsia showed no consistent relationship with the severity of preeclampsia.

Introducción: se ha identificado que los valores del colesterol y los triglicéridos (TG) son más altos en la preeclampsia que en el embarazo normal; sin embargo, aún no está claro si estos niveles tienen relación con la gravedad del proceso. El objetivo del estudio fue determinar si existe relación entre la dislipidemia y la gravedad en la preeclampsia. Métodos: estudio transversal comparativo en 200 pacientes, 100 con embarazo normal y 100 con preeclampsia. Se identificó edad, antecedentes ginecoobstétricos, colesterol total y TG. Se utilizó estadística descriptiva: t de Student para comparar el grupo de pacientes con preeclampsia y embarazos normales, y ANOVA y razón de momios para el subanálisis de preeclampsia leve y severa. Resultados: no se encontraron diferencias estadísticamente significativas en edad, ni en colesterol. Los TG presentaron una diferencia estadísticamente significativa: fueron más altos en relación con la gravedad de la preeclampsia (embarazo normal 245 mg, preeclampsia leve 308 mg y preeclampsia severa 349 mg). Conclusión: los niveles elevados de colesterol y TG en pacientes con preeclampsia no demostraron consistencia en relación con la gravedad de la preeclampsia.

Cytotoxicity of recombinant tamapin and related toxin-like peptides on model cell lines.

The scorpion toxin tamapin displays the most potent and selective blockage against KCa2.2 channels known to date. In this work, we report the biosynthesis, three-dimensional structure, and cytotoxicity on cancer cell lines (Jurkat E6-1 and human mammary breast cancer MDA-MB-231) of recombinant tamapin and five related peptides bearing mutations on residues (R6A,R7A, R13A, R6A-R7A, and GS-tamapin) that were previously suggested to be important for tamapin's activity. The indicated cell lines were used as they constitutively express KCa2.2 channels. The studied toxin-like peptides displayed lethal responses on Jurkat T cells and breast cancer cells; their effect is dose- and time-dependent with IC50 values in the nanomolar range. The order of potency is r-tamapin>GS-tamapin>R6A>R13A>R6A-R7A>R7A for Jurkat T cells and r-tamapin>R7A for MDA-MB-231 breast cancer cells. Our structural determination by NMR demonstrated that r-tamapin preserves the folding of the αKTx5 subfamily and that neither single nor double alanine mutations affect the three-dimensional structure of the wild-type peptide. In contrast, our activity assays show that changes in cytotoxicity are related to the chemical nature of certain residues. Our results suggest that the toxic activity of r-tamapin on Jurkat and breast cancer cells could be mediated by the interaction of charged residues in tamapin with KCa2.2 channels via the apoptotic cell death pathway.

Structure, function, and chemical synthesis of Vaejovis mexicanus peptide 24: a novel potent blocker of Kv1.3 potassium channels of human T lymphocytes.

Animal venoms are rich sources of ligands for studying ion channels and other pharmacological targets. Proteomic analyses of the soluble venom from the Mexican scorpion Vaejovis mexicanus smithi showed that it contains more than 200 different components. Among them, a 36-residue peptide with a molecular mass of 3864 Da (named Vm24) was shown to be a potent blocker of Kv1.3 of human lymphocytes (K(d) ∼ 3 pM). The three-dimensional solution structure of Vm24 was determined by nuclear magnetic resonance, showing the peptide folds into a distorted cystine-stabilized α/ß motif consisting of a single-turn α-helix and a three-stranded antiparallel ß-sheet, stabilized by four disulfide bridges. The disulfide pairs are formed between Cys6 and Cys26, Cys12 and Cys31, Cys16 and Cys33, and Cys21 and Cys36. Sequence analyses identified Vm24 as the first example of a new subfamily of α-type K(+) channel blockers (systematic number α-KTx 23.1). Comparison with other Kv1.3 blockers isolated from scorpions suggests a number of structural features that could explain the remarkable affinity and specificity of Vm24 toward Kv1.3 channels of lymphocytes.

New tricks of an old pattern: structural versatility of scorpion toxins with common cysteine spacing.

Scorpion venoms are a rich source of K(+) channel-blocking peptides. For the most part, they are structurally related small disulfide-rich proteins containing a conserved pattern of six cysteines that is assumed to dictate their common three-dimensional folding. In the conventional pattern, two disulfide bridges connect an α-helical segment to the C-terminal strand of a double- or triple-stranded ß-sheet, conforming a cystine-stabilized α/ß scaffold (CSα/ß). Here we show that two K(+) channel-blocking peptides from Tityus scorpions conserve the cysteine spacing of common scorpion venom peptides but display an unconventional disulfide pattern, accompanied by a complete rearrangement of the secondary structure topology into a CS helix-loop-helix fold. Sequence and structural comparisons of the peptides adopting this novel fold suggest that it would be a new elaboration of the widespread CSα/ß scaffold, thus revealing an unexpected structural versatility of these small disulfide-rich proteins. Acknowledgment of such versatility is important to understand how venom structural complexity emerged on a limited number of molecular scaffolds.

[Microangiopathy in preeclampsia: the usefulness of the peripheral blood smear]. / Microangiopatía en la preeclampsia: utilidad del frotis de sangre periférica.

Endothelial dysfunction is a fundamental characteristic in the physiopathology of preeclampsia. Currently, a series of markers which explain endothelial dysfunction have been identified. The recognition of endothelial dysfunction has been used to realize an early diagnosis of preeclampsia, as soon as the classification of a possible prognosis. Nevertheless the detection of these markers is not accessible to the majority of hospitable centers that treat patients with preeclampsia. One indirect marker of endothelial dysfunction with a greater accessibility is the assessment of peripheral blood smear. Several studies had proved the presence of endothelial dysfunction by identification of red blood cells crenated in peripheral blood smear led us also to measure the impact in the evolution of the disease.