Neurofibromatosis 1 (NF1) mutation results in impaired function of human induced pluripotent stem cell-derived microglia

Neurofibromatosis type 1 (NF1) is an autosomal dominant condition caused by germline mutations in the NF1 gene. Children with NF1 are prone to the development of multiple nervous system abnormalities, including autism and brain tumors, which could reflect the effect of NF1 mutation on microglia function. Using heterozygous Nf1-mutant mice, we previously demonstrated that impaired purinergic signaling underlies deficits in microglia process extension and phagocytosis in situ. To determine whether these abnormalities are also observed in human microglia in the setting of NF1, we leveraged an engineered isogenic series of human induced pluripotent stem cells to generate human microglia-like (hiMGL) cells heterozygous for three different NF1 patient-derived NF1 gene mutations. While all NF1-mutant and isogenic control hiMGL cells expressed classical microglia markers and exhibited similar transcriptomes and cytokine/chemokine release profiles, only NF1-mutant hiMGL cells had defects in P2X receptor activation, phagocytosis and motility. Taken together, heterozygous NF1 mutation impairs a subset of human microglia functional properties, which could contribute to the neurological abnormalities seen in children with NF1

Denkmahl der Hochachtung und Freundschaft dem Herrn geheimen Rath Schnauss zu Dessen ruhmwürdigen funfzigjährigen Amtsfeste geweihet von Deroselben ganz ergebenster Freundin J. S. Bohlin

DENKMAHL DER HOCHACHTUNG UND FREUNDSCHAFT DEM HERRN GEHEIMEN RATH SCHNAUSS ZU DESSEN RUHMWÜRDIGEN FUNFZIGJÄHRIGEN AMTSFESTE GEWEIHET VON DEROSELBEN GANZ ERGEBENSTER FREUNDIN J. S. BOHLIN Denkmahl der Hochachtung und Freundschaft dem Herrn geheimen Rath Schnauss zu Dessen ruhmwürdigen funfzigjährigen Amtsfeste geweihet von Deroselben ganz ergebenster Freundin J. S. Bohlin ([1]

Contact-free Mechanical Manipulation of Biological Materials

In biotechnology and medicine, controlled studies on biological material are fundamental for developing new methodologies and therapeutic approaches. To explore the nature of biological processes and to test inherent material properties, it has become increasingly clear that new experimental methods must be developed in order to allow precise manipulations and quantification of biological materials on the microscopic level. Traditional methods often rely on physical contact with the sample, which can induce drastic artifacts in soft biological systems. To bypass this limitation, tools for contact-free manipulation were developed, which even enable the induction of whole-cell deformations to explore their mechanical properties. These approaches facilitate extensive investigations of single molecules, molecular ensembles, cells and even tissues, potentially reducing the need for animal studies. In this rapidly changing field, it is nearly impossible to provide a comprehensive overview of all available techniques since new methods are constantly being developed. In this chapter, we highlight many of the predominant approaches, aiming to investigate cellular as well as subcellular mechanical properties and processes

Changing cell mechanics - a precondition for malignant transformation of oral squamous carcinoma cells

Oral squamous cell carcinomas (OSCC) are the sixth most common cancer and the diagnosis is often belated for a curative treatment. The reliable and early differentiation between healthy and diseased cells is the main aim of this study in order to improve the quality of the treatment and to understand tumour pathogenesis. Here, the optical stretcher is used to analyse mechanical properties of cells and their potential to serve as a marker for malignancy. Stretching experiments revealed for the first time that cells of primary OSCCs were deformed by 2.9% rendering them softer than cells of healthy mucosa which were deformed only by 1.9%. Furthermore, the relaxation behaviour of the cells revealed that these malignant cells exhibit a faster contraction than their benign counterparts. This suggests that deformability as well as relaxation behaviour can be used as distinct parameters to evaluate emerging differences between these benign and malignant cells. Since many studies in cancer research are performed with cancer cell lines rather than primary cells, we have compared the deformability and relaxation of both types, showing that long time culturing leads to softening of cells. The higher degree of deformability and relaxation behaviour can enable cancer cells to traverse tissue emphasizing that changes in cell architecture may be a potential precondition for malignant transformation. Respecting the fact that even short culture times have an essential effect on the significance of the results, the use of primary cells for further research is recommended. The distinction between malignant and benign cells would enable an early confirmation of cancer diagnoses by testing cell samples of suspect oral lesions