Hemifacial myohyperplasia is due to somatic muscular PIK3CA gain-of-function mutations and responds to pharmacological inhibition

Hemifacial myohyperplasia (HFMH) is a rare cause of facial asymmetry exclusively involving facial muscles. The underlying cause and the mechanism of disease progression are unknown. Here, we identified a somatic gain-of-function mutation of PIK3CA in five pediatric patients with HFMH. To understand the physiopathology of muscle hypertrophy in this context, we created a mouse model carrying specifically a PIK3CA mutation in skeletal muscles. PIK3CA gain-of-function mutation led to striated muscle cell hypertrophy, mitochondria dysfunction, and hypoglycemia with low circulating insulin levels. Alpelisib treatment, an approved PIK3CA inhibitor, was able to prevent and reduce muscle hypertrophy in the mouse model with correction of endocrine anomalies. Based on these findings, we treated the five HFMH patients. All patients demonstrated clinical, esthetical, and radiological improvement with proof of target engagement. In conclusion, we show that HFMH is due to somatic alteration of PIK3CA and is accessible to pharmacological intervention.

PIK3CA gain-of-function mutation in adipose tissue induces metabolic reprogramming with Warburg-like effect and severe endocrine disruption

PIK3CA-related overgrowth syndrome (PROS) is a genetic disorder caused by somatic mosaic gain-of-function mutations of PIK3CA. Clinical presentation of patients is diverse and associated with endocrine disruption. Adipose tissue is frequently involved, but its role in disease development and progression has not been elucidated. Here, we created a mouse model of PIK3CA-related adipose tissue overgrowth that recapitulates patient phenotype. We demonstrate that PIK3CA mutation leads to GLUT4 membrane accumulation with a negative feedback loop on insulin secretion, a burst of liver IGFBP1 synthesis with IGF-1 sequestration, and low circulating levels. Mouse phenotype was mainly driven through AKT2. We also observed that PIK3CA mutation induces metabolic reprogramming with Warburg-like effect and protein and lipid synthesis, hallmarks of cancer cells, in vitro, in vivo, and in patients. We lastly show that alpelisib is efficient at preventing and improving PIK3CA-adipose tissue overgrowth and reversing metabolomic anomalies in both animal models and patients.

Alpelisib administration reduced lymphatic malformations in a mouse model and in patients

[Figure: see text].

Immunodynamics of explanted human tumors for immuno-oncology

Decision making in immuno‐oncology is pivotal to adapt therapy to the tumor microenvironment (TME) of the patient among the numerous options of monoclonal antibodies or small molecules. Predicting the best combinatorial regimen remains an unmet medical need. Here, we report a multiplex functional and dynamic immuno‐assay based on the capacity of the TME to respond to ex vivo stimulation with twelve immunomodulators including immune checkpoint inhibitors (ICI) in 43 human primary tumors. This "in sitro" (in situ/in vitro) assay has the potential to predict unresponsiveness to anti‐PD‐1 mAbs, and to detect the most appropriate and personalized combinatorial regimen. Prospective clinical trials are awaited to validate this in sitro assay.

Hip Fracture Leads to Transitory Immune Imprint in Older Patients

Background: Hip fracture (HF) is common in the geriatric population and is associated with a poor vital and functional prognosis which could be impacted by immunological changes. The objective here is to decipher immune changes occurring in the 1st days following HF and determine how phenotype, function, and regulation of innate and adaptive compartments adapt during acute stress event.

Methods: We included HF patients, aged over 75 years. For each patient, blood samples were taken at five different timepoints: four in the perioperative period (day 0 to hospital discharge) and one at long term (6–12 months). Phenotypical and functional analysis were performed longitudinally on fresh blood or cryopreserved PBMCs. Clinical data were prospectively collected.

Results: One-hundred HF patients and 60 age-matched controls were included. Innate compartment exhibits pro-inflammatory phenotypes (hyperleukocytosis, increase of CD14+ CD16+ proportion and CCR2 expression), maintaining its ability to produce pro-inflammatory cytokines. Adaptive compartment extends toward a transitory immunosuppressive profile (leucopenia) associated with an active T-cell proliferation. Furthermore, increases of LAG-3 and PD-1 and a decrease of 2-B4 expression are observed on T-cells, reinforcing their transitory suppressive status. Of note, these immune changes are transitory and sequential but may participate to a regulation loop necessary for homeostatic immune control at long term.

Conclusion: HF is associated with several transitory immunological changes including pro-inflammatory phenotype in innate compartment and immunosuppressive profile in adaptive compartment. A comprehensive assessment of immune mechanisms implicated in the patient's prognosis after HF could pave the way to develop new immune therapeutics strategies.

An Optimized Lentiviral Vector Efficiently Corrects the Human Sickle Cell Disease Phenotype

Autologous transplantation of hematopoietic stem cells transduced with a lentiviral vector (LV) expressing an anti-sickling HBB variant is a potential treatment for sickle cell disease (SCD). With a clinical trial as our ultimate goal, we generated LV constructs containing an anti-sickling HBB transgene (HBBAS3), a minimal HBB promoter, and different combinations of DNase I hypersensitive sites (HSs) from the locus control region (LCR). Hematopoietic stem progenitor cells (HSPCs) from SCD patients were transduced with LVs containing either HS2 and HS3 (β-AS3) or HS2, HS3, and HS4 (β-AS3 HS4). The inclusion of the HS4 element drastically reduced vector titer and infectivity in HSPCs, with negligible improvement of transgene expression. Conversely, the LV containing only HS2 and HS3 was able to efficiently transduce SCD bone marrow and Plerixafor-mobilized HSPCs, with anti-sickling HBB representing up to ∼60% of the total HBB-like chains. The expression of the anti-sickling HBB and the reduced incorporation of the β^S-chain in hemoglobin tetramers allowed up to 50% reduction in the frequency of RBC sickling under hypoxic conditions. Together, these results demonstrate the ability of a high-titer LV to express elevated levels of a potent anti-sickling HBB transgene ameliorating the SCD cell phenotype.

Elderly human hematopoietic progenitor cells express cellular senescence markers and are more susceptible to pyroptosis

The maintenance of effective immunity over time is dependent on the capacity of hematopoietic stem cells (HSCs) to sustain the pool of immunocompetent mature cells. Decline of immune competence with old age may stem from HSC defects, including reduced self-renewal potential and impaired lymphopoiesis, as suggested in murine models. To obtain further insights into aging-related alteration of hematopoiesis, we performed a comprehensive study of blood hematopoietic progenitor cells (HPCs) from older humans. In the elderly, HPCs present active oxidative phosphorylation and are pressed to enter cell cycling. However, p53-p21 and p15 cell senescence pathways, associated with telomerase activity deficiency, strong telomere attrition, and oxidative stress, are engaged, thus limiting cell cycling. Moreover, survival of old HPCs is impacted by pyroptosis, an inflammatory form of programmed cell death. Lastly, telomerase activity deficiency and telomere length attrition of old HPCs may be passed on to progeny cells such as naive T lymphocytes, further highlighting the poor hematopoietic potential of the elderly. This pre-senescent profile is characteristic of the multiple intrinsic and extrinsic factors affecting HPCs in elderly individuals and represents a major obstacle in terms of immune reconstitution and efficacy with advanced age.

Elevated Neopterin Levels Predict Early Death in Older Hip-fracture Patients

Our society faces a major challenge concerning management of the health and socio-economic burden caused by acute physical stress in the older population (+ 75 years). In particular, hip-fracture surgery (HFS) represents a major health care preoccupation, affecting 1.6 million patients worldwide, resulting in a significant drop in life quality and autonomy. The trauma is associated with 20–30% one-year mortality in the elderly. In the present study, we aim to identify factors, which influence and/or predict the outcome of elderly hip- fracture patients (HFP) post-surgery.

Our objective was to identify biomarkers with a prognostic capacity of one-year mortality. We employed an observational cohort of HFP (n = 60) followed-up longitudinally during the first year post fracture. Clinical and biological data (n = 136), collected at arrival to hospital, were then compared to healthy controls (n = 42) and analyzed using a regularized logistic regression model with lasso penalty followed by 10-fold cross-validation of variables.

We show that plasmatic neopterin levels, a molecule released by IFN-γ-activated macrophages, is predictive of mortality in HFP (ROC-AUC = 0.859). Moreover, neopterin measured at arrival to the hospital correlated negatively with the time of survival after HFS.

Neopterin therefore represents a biomarker, which enables better follow-up of patients at risk of early death.

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Neopterin level, measured at arrival to hospital, is a robust predictive marker of one-year mortality in HFPs.

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Neopterin concentration correlated negatively with the time of survival after hip fracture surgery.

The growing incidence of hip fractures, due to demographically aging populations, represent an important burden for health care systems and for injured patients in terms of hospitalization, rehabilitation, needs for long-term care, change in autonomy and mortality. Hip fractures are associated with high rates of adverse outcome, but previous studies have not discovered methods to identify patients at high risk of pernicious clinical outcome or death. Here, we show that innate immune activation post hip fracture in older adults is associated with pernicious clinical outcome.

Preservation of Lymphopoietic Potential and Virus Suppressive Capacity by CD8+ T Cells in HIV-2-Infected Controllers

Compared with HIV-1, HIV-2 infection is characterized by a larger proportion of slow or nonprogressors. A better understanding of HIV-2 pathogenesis should open new therapeutic avenues to establish control of HIV-1 replication in infected patients. In this study, we studied the production of CD8(+) T cells and their capacity for viral control in HIV-2 controllers from the French ANRS CO5 HIV-2 cohort. HIV-2 controllers display a robust capacity to support long-term renewal of the CD8(+) T cell compartment by preserving immune resources, including hematopoietic progenitors and thymic activity, which could contribute to the long-term maintenance of the CD8(+) T cell response and the avoidance of premature immune aging. Our data support the presence of HIV-2 Gag-specific CD8(+) T cells that display an early memory differentiation phenotype and robust effector potential in HIV-2 controllers. Accordingly, to our knowledge, we show for the first time that HIV-2 controllers possess CD8(+) T cells that show an unusually strong capacity to suppress HIV-2 infection in autologous CD4(+) T cells ex vivo, an ability that likely depends on the preservation of host immune resources. This effective and durable antiviral response probably participates in a virtuous circle, during which controlled viral replication permits the preservation of potent immune functions, thus preventing HIV-2 disease progression.

Nesidioblastosis associated with hyperinsulinemic hypoglycemia in adults: review of the literature

Nesidioblastosis is a term that was first introduced by Laidlaw in 1938 to define the diffuse proliferation of pancreatic islet cells budding from ductal epithelium. First described in neonates, it is widely recognized to be the primary cause of persistent hyperinsulinemic hypoglycemia in infants. In adults, insulinoma accounts for most cases of hyperinsulinemic hypoglycemia. Adult-onset nesidioblastosis associated with hyperinsulinemic hypoglycemia is a very rare entity, representing 0.5-5% of cases of organic hyperinsulinemia. Since 1981, when Harness et al. reported the first series of adult nesidioblastosis causing hypoglycemia, only 71 cases have been published. This article provides a guide for the diagnosis of organic hyperinsulinism and indicates when nesidioblastosis should be suspected. New diagnostic methods and treatment options for this rare disease are proposed. We also present a review of all reported cases of adult nesidioblastosis in the last 22 years.

Bioanalytical characterization of proteins

Allergens from the view of a protein chemist are quite normal proteins, not to distinguish from non allergenic proteins. The first task is therefore to recognize and identify the proteins responsible for the allergenic reaction. This is usually only possible if the allergenic structure is conserved during the purification procedures. For a detailed analysis of the allergenic protein modern protein chemical methods for characterization, identification, determination of posttranslational modifications and epitope characterization have to be applied. Such techniques are briefly described in this article.

Mapping of IgE binding regions in the major rat urinary protein, alpha 2u-globulin, using overlapping peptides

Exposure to laboratory animals poses a hazard for development of occupational allergy. Identification of antigenic determinants of allergenic proteins may be valuable for immunotherapeutic purposes. Overlapping peptides of the major allergen in rat urine, Rat n 1.02, corresponding to the protein alpha2u-globulin were synthesised on solid support and screened simultaneously to locate IgE binding linear epitopes using a simple modified ELISA procedure. Thirty-nine peptides were synthesised, each 8 amino acids long with 4 amino acids overlaps. Sera from fifteen rat-sensitized subjects were analyzed and as controls sera from 7 non-rat-sensitized individuals were used. In general low binding and a great individual variation between sera from rat allergic individuals were seen. Some peptides were more frequently recognized by IgE antibodies in sera from rat allergics. These peptides were mainly clustered towards the N-terminal and C-terminal parts of the protein. Taken together our data suggest the existence of linear IgE binding epitopes in the rat urine allergen, Rat n 1.02. However, the role of these sequences in the allergic reaction needs further investigation.

Rat urinary proteins binding human IgE detected by chemiluminescence

Work with laboratory animals involves the increased risk of developing an allergy. Certain proteins in male rat urine have been shown to be major allergens, i.e., Rat n 1.01 and Rat n 1.02. Rat urinary proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were electro-blotted to polyvinylidene difluoride (PVDF) membranes. Immunoblot analysis of human IgE binding components in rat urine utilizing chemiluminescence and a newly developed luminometer is described. Luminometer scanning curves of IgE reactivity to the separated rat urinary proteins are demonstrated. Rat allergic individuals showed different immune responses to the separated proteins. Rat n 1.02, also known as the major protein alpha2mu-globulin, was not always the dominant allergen. Another protein in the albumin region, 60-67 kDa, was found to be an important allergen to some rat-sensitive subjects. Reactivity in the skin prick test with purified Rat n 1.01 and Rat n 1.02 fractions were strong. However, in dot blot under nondenaturing conditions, only weak responses were obtained to the purified rat urinary proteins except for the albumin fraction. Chemiluminescence measurements in blotting membranes of patient IgE bound to different dilutions of certain rat urine proteins revealed good quantitative relationships. Three different chemiluminescence substrates were tested. Measurement of IgE bound to individual allergens as well as the abundance and relative importance of various allergens were studied.

Visualization and quantification of birch-pollen allergens directly on air-sampling filters

A new technique is presented to detect and quantify birch (Betula pendula)-pollen allergens directly on air-sampling filters. It is based on the use of specific antibodies, enzymatic reactions, and measurement by chemiluminescence or densitometry. The major pollen antigens are the most important birch allergens. The antibodies used recognize birch-pollen antigens which thus correspond to allergens. Calibration was done with a standardized extract of birch pollen for skin prick testing. The correlation coefficient for the logarithms of luminescence and the amount of birch-pollen allergen applied on filters was > 0.98 in the range 0.04-200 SQ units. A similar correlation was found for the logarithms of the integrated densitometry values and the amount of birch-pollen allergen applied on filters. The number of major pollen-antigen particles or grains on filters could be estimated by counting the major stained spots produced by precipitated enzymatic products. The correlation coefficient was 0.90 for the logarithms of the number of counted major antigen spots and the calculated antigen amount obtained by luminometric measurements. Our results demonstrate that birch-pollen allergens can be determined directly on air-sampling, Teflon-based filters by luminometry, optical density, or particle counting.

A new amplified monoclonal rat allergen assay used for evaluation of ventilation improvements in animal rooms

BACKGROUND

Available methods for the measurement of airborne laboratory animal allergens are not standardized and are often insufficiently sensitive for measurements in laboratories or in undisturbed animal rooms. Although low, the levels may be clinically relevant, because many scientists not involved in cleaning out cages or handling animals have rodent allergies.

OBJECTIVE

The purpose of this study was to develop a sensitive monoclonal assay to determine airborne rat allergen and test it in the evaluation of a sliding curtain system installed in refurbished rat rooms, with perforated, transparent polycarbonate screens, behind which were the cage racks.

METHODS

Monoclonal antibodies were produced against male rat urine by immunization in mice and fusion with mouse cell line Sp2/0. A novel biotinylated phenol compound was synthesized for immunoassay signal amplification in conjunction with horseradish peroxidase. Air filter samples were collected at a rate of 2 L/min, and allergen content in the filter eluates was determined.

RESULTS

Two monoclonal antibodies were produced and used in a sandwich ELISA, which bound alpha2u-globulin (Rat n 1.02). The assay detection limit was 3.2 pg/ml, about tenfold increased sensitivity compared with the unamplified assay. Allergen levels were lower in rooms when curtains were closed (median, 0.2 ng/m3) than behind the curtains (0.9 ng/m3, p = 0.01) or if the curtains were open (0.9 ng/m3, p = 0.001). However, allergen levels during cage cleaning, when curtains were drawn apart, were high (18 ng/m3).

CONCLUSION

We have developed a method for measurement of airborne rat allergen that can be standardized, measures an important allergen, and is sufficiently sensitive to measure low allergen levels with personal samplers.

Purification and identification of allergenic alpha (2u)-globulin species of rat urine

Amino-acid compositional and sequence analyses as well as mass spectrometric determinations of purified rat urine proteins, previously termed prealbumin and alpha(2)-euglobulin, have revealed a high homology between the two forms which have now been identified as alpha(2)-globulin species. The "prealbumin' fraction was found to correspond to alpha(2u)-globulin originating from salivary gland and the 'alpha(2)-euglobulin' fraction was identical with the major urinary protein (MUP) or alpha(2u)-globulin. The results indicate that the two major protein fractions of rat urine constitute different forms of the same parent protein, alpha(2u)-globulin, having no amino-acid sequence resemblance to prealbumin (transthyretin) of rat serum.

Sensitive quantification of proteins by electrophoresis in gels by use of chemiluminescence

For protein quantitation in gels or blotting membranes, chemiluminescence (CL) offers the advantages of a substantial improvement of detection limits. Easy-to-use CL-chemicals and specific probes such as antibodies conjugated to enzymes, e.g. alkaline phosphatase (AP) may be used in combination with a newly developed luminometer. CL was found to have low detection limits and a linear relation between relative light units (RLU) and the concentration of the antibody enzyme complex present over a wide concentration range. Measurements of the immunoglobulin IgE in dot blots and in blots after sodium dodecyl sulfate (SDS) electrophoresis under nonreducing conditions in agarose gels are described.

Electrophoretic analysis of stimulated cat parotid saliva

The proteins of parasympathetically stimulated cat parotid saliva were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and high resolution two-dimensional electrophoresis (2-DE). SDS-PAGE revealed up to 30 polypeptide bands in microliter volumes of unconcentrated saliva. The patterns were highly reproducible and characterized by prominent bands of M(r) 57,000, M(r) 30,000 and M(r) 15,000. The major protein (M(r) 30,000) appeared as a dimer (M(r) 60,000) when electrophoresed under non-reducing conditions but dissociated into its monomeric form when the SDS concentration of the denatured samples was increased from 1 to 5%. This indicates a noncovalent association. The protein patterns of saliva from different cats differed slightly but sequential samples from the same cat (collected during 90 min of stimulation) showed little change in protein pattern apart from a fall in total protein content. Following 2-DE, the major protein (M(r) 30,000) appeared as a complex array of at least eight spots in two tiers (pI 5.2-6.2; M(r) 28,000 and 32,000). The characteristics of this protein are discussed with reference to allergy to cats.