Cytotoxic Staphylococcus aureus PSMα3 inhibits the aggregation of human insulin in vitro.

Phenol-soluble modulins (PSMs) are extracellular short amphipathic peptides secreted by the bacteria Staphylococcus aureus (S. aureus). They play an essential role in the bacterial lifecycle, biofilm formation, and stabilisation. From the PSM family, PSMα3 has been of special interest recently due to its cytotoxicity and highly stable α-helical conformation, which also remains in its amyloid fibrils. In particular, PSMα3 fibrils were shown to be composed of self-associating "sheets" of α-helices oriented perpendicular to the fibril axis, mimicking the architecture of canonical cross-ß fibrils. Therefore, they were called cross-α-fibrils. PSMα3 was synthesised and verified for identity with wild-type sequences (S. aureus). Then, using several experimental techniques, we evaluated its propensity for in vitro aggregation. According to our findings, synthetic PSMα3 (which lacks the N-terminal formyl groups found in bacteria) does not form amyloid fibrils and maintains α-helical conformation in a soluble monomeric form for several days of incubation. We also evaluated the influence of PSMα3 on human insulin fibrillation in vitro, using a variety of experimental approaches in combination with computational molecular studies. First, it was shown that PSMα3 drastically inhibits the fibrillation of human insulin. The anti-fibrillation effect of PSMα3 was concentration-dependent and required a concentration ratio of PSMα3: insulin equal to or above 1 : 100. Molecular modelling revealed that PSMα3 most likely inhibits the production of insulin primary nuclei by competing for residues involved in its dimerization.

Regulatory T cells contribute to the immunosuppressive phenotype of neutrophils in a mouse model of chronic lymphocytic leukemia.

BACKGROUND: Impaired neutrophil activity is an important issue in chronic lymphocytic leukemia (CLL), as it contributes to a dysfunctional immune response leading to life-threatening infections in patients. Some features typical of CLL neutrophils, e.g., the B-cell-supportive secretion profile, have already been described. However, most of these studies were performed on cells isolated from peripheral blood. It is still unclear which molecular factors and cell types are involved in shaping neutrophil function and phenotype in the CLL microenvironment. Since regulatory T cells (Treg) play an important role in CLL progression and influence the activity of neutrophils, we investigated the crosstalk between Treg and neutrophils in the spleen using a murine model of CLL. METHODS: In this work, we used an Eµ-TCL1 mouse model of human CLL. For our in vivo and ex vivo experiments, we inoculated wild-type mice with TCL1 leukemic cells isolated from Eµ-TCL1 transgenic mice and then monitored disease progression by detecting leukemic cells in peripheral blood. We analyzed both the phenotype and activity of neutrophils isolated from the spleens of TCL1 leukemia-bearing mice. To investigate the interrelation between Treg and neutrophils in the leukemia microenvironment, we performed experiments using TCL1-injected DEREG mice with Treg depletion or RAG2KO mice with adoptively transferred TCL1 cells alone or together with Treg. RESULTS: The obtained results underline the plasticity of the neutrophil phenotype, observed under the influence of leukemic cells alone and depending on the presence of Treg. In particular, Treg affect the expression of CD62L and IL-4 receptor in neutrophils, both of which are crucial for the function of these cells. Additionally, we show that Treg depletion and IL-10 neutralization induce changes in the leukemia microenvironment, partially restoring the "healthy" phenotype of neutrophils. CONCLUSIONS: Altogether, the results indicate that the crosstalk between Treg and neutrophils in CLL may play an important role in CLL progression by interfering with the immune response.

In Situ Programming of CAR-T Cells: A Pressing Need in Modern Immunotherapy.

Chimeric antigen receptor-T (CAR-T) cell-based therapy has become a successful option for treatment of numerous hematological malignancies, but also raises hope in a range of non-malignant diseases. However, in a traditional approach, generation of CAR-T cells is associated with the separation of patient's lymphocytes, their in vitro modification, and expansion and infusion back into patient's bloodstream. This classical protocol is complex, time-consuming, and expensive. Those problems could be solved by successful protocols to produce CAR-T cells, but also CAR-natural killer cells or CAR macrophages, in situ, using viral platforms or non-viral delivery systems. Moreover, it was demonstrated that in situ CAR-T induction may be associated with reduced risk of the most common toxicities associated with CAR-T therapy, such as cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, and "on-target, off-tumor" toxicity. This review aims to summarize the current state-of-the-art and future perspectives for the in situ-produced CAR-T cells. Indeed, preclinical work in this area, including animal studies, raises hope for prospective translational development and validation in practical medicine of strategies for in situ generation of CAR-bearing immune effector cells.

Pericapsular Nerves Group (PENG) Block in Children under Five Years of Age for Analgesia in Surgery for Hip Dysplasia: Case Report.

INTRODUCTION: The Pericapsular Nerve Group (PENG) block is a novel technique that allows for analgesia of the anterior hip capsule via the articular branches of the accessory obturator nerve and femoral nerve, which have a significant role in the innervation of the hip capsule. A PENG (Pericapsular Nerves Group) blockade is effective in both adult and pediatric patients. However, no studies on patients under five are available in the literature. Herein, we describe our experience with two pediatric patients with hip dysplasia. PURPOSE: This study aimed to evaluate the analgesic effect of the pericapsular nerves group (PENG) in preschool children undergoing hip surgery. PATIENTS AND METHODS: This study included two patients, aged 4 and 2 years old, who were qualified for hip surgery. Spinal or general anesthesia with the addition of a PENG block was performed. During the procedure, the basic hemodynamic parameters were monitored. The pain was assessed using the FALCC (Face, Legs, Activity, Cry, Consolability scale) score. A dose of 15 mg/kg-1 of metamizole was administered if the FLACC score was 3. In the case of a score of 4 on the FLACC scale, the application of 0.2 mg/kg-1 of nalbuphine was ordered. RESULTS: After the surgery, the patients received 15 mg/kg-1 IV paracetamol every 6 h to prevent rebound pain. The patient's hemodynamic parameters were stable and within normal range. In the first 24 h period, the FLACC scores from all patients ranged from 0 to 3. One patient required metamizole 12 h after surgery. No evidence of block complications was observed. CONCLUSIONS: This case series showed that the PENG block assured opioid-free pain management and provided adequate postoperative analgesia. However, we are convinced that future randomized, controlled trials are needed in this field.

The Role of Neutrophils in the Pathogenesis of Chronic Lymphocytic Leukemia.

Tumor-associated neutrophils appear to be a crucial element of the tumor microenvironment that actively participates in the development and progression of cancerous diseases. The increased lifespan, plasticity in changing of phenotype, and functions of neutrophils influence the course of the disease and may significantly affect survival. In patients with chronic lymphocytic leukemia (CLL), disturbances in neutrophils functions impede the effective immune defense against pathogens. Therefore, understanding the mechanism underlying such a phenomenon in CLL seems to be of great importance. Here we discuss the recent reports analyzing the phenotype and functions of neutrophils in CLL, the most common leukemia in adults. We summarize the data concerning both the phenotype and the mechanisms by which neutrophils directly support the proliferation and survival of malignant B cells.

Bilateral chronic subdural haematomas in a patient with meningioma of the superior sagittal sinus - case report and pathophysiological study.

Bilateral chronic subdural haemorrhage accompanying meningioma is a very rare clinical condition. We present a case of a 69-year-old female patient with large meningioma completely obliterating the posterior third part of the superior sagittal sinus with accompanying bilateral chronic subdural haematomas. Three anatomical zones of venous collateral circulation were revealed by the preoperative digital subtraction angiography. The tumour and haematomas were removed completely with no major complications. The most likely pathomechanism of the development of bilateral chronic subdural haematomas was venous hypertension caused by an occlusion of major cerebral venous trunks. As a result of a minor thrombotic incident or insignificant head injury, the distended veins of collateral circulation that were volumetrically burdened could have been damaged. Patients with large tumours occluding the superior sagittal sinus, who did not qualify for or refused surgery, should be carefully monitored clinically and neuroradiologically because of possibly increased risk of an intracranial haemorrhage.

Mutations in the von hippel-lindau tumour suppressor gene in central nervous system hemangioblastomas.

Central nervous system hemangioblastomas (cHAB) are rare tumours which most commonly arise in the cerebellum. Most tumours are sporadic, but as many as one third of cHABs occur in the course of the hereditary disorder - von Hippel-Lindau disease (VHL). In order to diagnose new VHL families in Poland we performed sequencing of the entire VHL gene in archival material (paraffin embedded hemangioblastoma tissues) in a large series of 203 unselected patients with cHAB. VHL gene mutations were detected in 70 (41%) of 171 tumour samples from which DNA of relatively good quality was isolated. We were able to obtain blood samples from 19 of mutation positive cases. Eight (42%) of these harboured germline mutations in persons from distinct undiagnosed VHL families.