A Systematic Review Examining the Experimental Methodology Behind In Vivo Testing of Hiatus Hernia and Diaphragmatic Hernia Mesh

Introduction Mesh implants are regularly used to help repair both hiatus hernias (HH) and diaphragmatic hernias (DH). In vivo studies are used to test not only mesh safety, but increasingly comparative efficacy. Our work examines the field of in vivo mesh testing for HH and DH models to establish current practices and standards. Method This systematic review was registered with PROSPERO. Medline and Embase databases were searched for relevant in vivo studies. Forty-four articles were identified and underwent abstract review, where 22 were excluded. Four further studies were excluded after full-text review—leaving 18 to undergo data extraction. Results Of 18 studies identified, 9 used an in vivo HH model and 9 a DH model. Five studies undertook mechanical testing on tissue samples—all uniaxial in nature. Testing strip widths ranged from 1–20 mm (median 3 mm). Testing speeds varied from 1.5–60 mm/minute. Upon histology, the most commonly assessed structural and cellular factors were neovascularisation and macrophages respectively (n = 9 each). Structural analysis was mostly qualitative, where cellular analysis was equally likely to be quantitative. Eleven studies assessed adhesion formation, of which 8 used one of four scoring systems. Eight studies measured mesh shrinkage. Discussion In vivo studies assessing mesh for HH and DH repair are uncommon. Within this relatively young field, we encourage surgical and materials testing institutions to discuss its standardisation.

USP1 Promotes GC Metastasis via Stabilizing ID2

Gastric cancer (GC) is one of the most common malignant tumors all over the world. And recurrence and metastasis are still the main causes of low survival rate for advanced GC. USP1 has been shown overexpressed in multiple cancers, which indicate its important biomarker in tumorigenesis and development. Our study is aimed at defining the exact role of USP1 on GC metastasis and the underlying mechanism. USP1 was firstly found overexpressed in GC tissues and relatively high-expression levels conferred poor survival rates. Then, real-time cellular analysis (RTCA) showed that USP1 knockdown inhibited GC metastasis both in vitro and in vivo. Mechanically, we demonstrated that USP1 promoted GC metastasis via upregulating ID2 expression and further confirmed that USP1 stabilized ID2 expression through deubiquitinating ID2 in GC. In conclusion, our study showed that USP1 promoted GC metastasis via stabilizing ID2 expression, which provides a potential biomarker and therapy target for GC.

PrPC as a Transducer of Physiological and Pathological Signals

After the discovery of prion phenomenon, the physiological role of the cellular prion protein (PrPC) remained elusive. In the past decades, molecular and cellular analysis has shed some light regarding interactions and functions of PrPC in health and disease. PrPC, which is located mainly at the plasma membrane of neuronal cells attached by a glycosylphosphatidylinositol (GPI) anchor, can act as a receptor or transducer from external signaling. Although the precise role of PrPC remains elusive, a variety of functions have been proposed for this protein, namely, neuronal excitability and viability. Although many issues must be solved to clearly define the role of PrPC, its connection to the central nervous system (CNS) and to several misfolding-associated diseases makes PrPC an interesting pharmacological target. In a physiological context, several reports have proposed that PrPC modulates synaptic transmission, interacting with various proteins, namely, ion pumps, channels, and metabotropic receptors. PrPC has also been implicated in the pathophysiological cell signaling induced by β-amyloid peptide that leads to synaptic dysfunction in the context of Alzheimer’s disease (AD), as a mediator of Aβ-induced cell toxicity. Additionally, it has been implicated in other proteinopathies as well. In this review, we aimed to analyze the role of PrPC as a transducer of physiological and pathological signaling.

Multiple alterations in glutamatergic transmission and dopamine D2 receptor splicing in induced pluripotent stem cell-derived neurons from patients with familial schizophrenia

An increasing body of evidence suggests that impaired synapse development and function are associated with schizophrenia; however, the underlying molecular pathophysiological mechanism of the disease remains largely unclear. We conducted a family-based study combined with molecular and cellular analysis using induced pluripotent stem cell (iPSC) technology. We generated iPSCs from patients with familial schizophrenia, differentiated these cells into neurons, and investigated the molecular and cellular phenotypes of the patient’s neurons. We identified multiple altered synaptic functions, including increased glutamatergic synaptic transmission, higher synaptic density, and altered splicing of dopamine D2 receptor mRNA in iPSC-derived neurons from patients. We also identified patients’ specific genetic mutations using whole-exome sequencing. Our findings support the notion that altered synaptic function may underlie the molecular and cellular pathophysiology of schizophrenia, and that multiple genetic factors cooperatively contribute to the development of schizophrenia.

B and T Cell Responses after a Third Dose of SARS-CoV-2 Vaccine in Kidney Transplant Recipients

Background: Accumulating evidence suggests that solid organ transplant recipients, as opposed to the general population, show strongly impaired responsiveness towards standard SARS-CoV-2 mRNA-based vaccination, demanding alternative strategies for protection of this vulnerable group. Methods: In line with recent recommendations, a third dose of either heterologous ChAdOx1 (AstraZeneca) or homologous BNT162b2 (BioNTech) was administered to 25 kidney transplant recipients (KTR) without humoral response after 2 doses of BNT162b2, followed by analysis of serological responses and vaccine-specific B- and T-cell immunity. Results: 9/25 (36%) KTR under standard immunosuppressive treatment seroconverted until day 27 after the third vaccination, while one patient developed severe COVID-19 infection immediately after vaccination. Cellular analysis seven days after the third dose showed significantly elevated frequencies of viral spike protein receptor binding domain specific B cells in humoral responders as compared to non-responders. Likewise, portions of spike-reactive CD4+ T helper cells were significantly elevated in seroconverting patients. Furthermore, overall frequencies of IL-2+, IL-4+ and polyfunctional CD4+ T cells significantly increased after the third dose, whereas memory/effector differentiation remained unaffected. Conclusions: Our data suggest that a fraction of transplant recipients benefits from triple vaccination, where seroconversion is associated with quantitative and qualitative changes of cellular immunity. At the same time, the study highlights that modified vaccination approaches for immunosuppressed patients still remain an urgent medical need.

Flow cytometry and pharmacokinetics

Multiparametric flow cytometry is a powerful cellular analysis tool used in various stages of drug development. In adoptive cell therapies, the flow cytometry methods are used for the evaluation of advanced cellular products during manufacturing and to monitor cellular kinetics after infusion. In this report, we discussed the bioanalytical method development challenges to monitor cellular kinetics in CAR-T cell therapies. These method development challenges include procuring positive control samples for the development of the method, flow cytometry panel design, LLOQ, prestain sample stability, staining reagents and data analysis.

Comparative cellular analysis of motor cortex in human, marmoset and mouse

The primary motor cortex (M1) is essential for voluntary fine-motor control and is functionally conserved across mammals1. Here, using high-throughput transcriptomic and epigenomic profiling of more than 450,000 single nuclei in humans, marmoset monkeys and mice, we demonstrate a broadly conserved cellular makeup of this region, with similarities that mirror evolutionary distance and are consistent between the transcriptome and epigenome. The core conserved molecular identities of neuronal and non-neuronal cell types allow us to generate a cross-species consensus classification of cell types, and to infer conserved properties of cell types across species. Despite the overall conservation, however, many species-dependent specializations are apparent, including differences in cell-type proportions, gene expression, DNA methylation and chromatin state. Few cell-type marker genes are conserved across species, revealing a short list of candidate genes and regulatory mechanisms that are responsible for conserved features of homologous cell types, such as the GABAergic chandelier cells. This consensus transcriptomic classification allows us to use patch–seq (a combination of whole-cell patch-clamp recordings, RNA sequencing and morphological characterization) to identify corticospinal Betz cells from layer 5 in non-human primates and humans, and to characterize their highly specialized physiology and anatomy. These findings highlight the robust molecular underpinnings of cell-type diversity in M1 across mammals, and point to the genes and regulatory pathways responsible for the functional identity of cell types and their species-specific adaptations.

Elevated 2HG does not cause features of tumorigenesis

Aims Gliomas are the most frequent brain tumours, representing 75% of all primary malignant brain tumours in adults. IDH1 (and IDH2) driver mutations occur in >80% of low grade gliomas and secondary GBMs, in <10% of primary GBMs and other cancers. How IDH1/2 mutations contribute to tumorigenesis is mostly unknown. IDH1/2 convert isocitrate to α-ketoglutarate, but when mutated possess a novel enzymatic function that reduces α-ketoglutarate to D2-hydroxyglutarate (2HG). Indeed 2HG accumulates in IDH1/2-mutant tumours, and this discovery suggested that 2HG may have a role in IDH1/2-mutant tumours onset and progression, possibly by causing dysregulations of various enzymes in the cells. Studies are undergoing to clarify the causative role of 2HG in IDH1/2-mutant tumours, but it is still not clear whether 2HG is the driver/oncometabolite. Our aim is to understand the role of 2HG in developing and adult mouse tissues and whether its accumulation might cause features of gliomagenesis. Method A constitutive D2hgdh Knock-out mouse (D2hgdh KO) was generated and the relative molecular and cellular analysis were performed. Results Brains dissected from D2hgdh KO mice appeared to be histologically normal. No differences were found in the proliferation and labelling retaining capacity of neural stem and progenitors cells (NSC/NPC) of the D2hgdh KO mice compared to controls. A comprehensive metabolites analysis showed that D2hgdh KO mouse accumulated 2HG in various organs and tissues, included total brains and in the NSC/NPC microdissected from the subventricular zone, the site of origin of many human gliomas. The DNA amount of 5mC and 5hmC extracted from brains of D2hgdh KO mice was similar to controls. A normal number of haematopoietic progenitors was also found. Conclusion Although D2hgdh KO mice accumulated 2HG in all tissues analysed, they did not develop any abnormalities and remained completely asymptomatic. This suggests that a mere increment of 2HG in developing and adult tissues may be not sufficient to cause tumorigenesis (and gliomagenesis), leading some doubts on the oncogenic roles of the 2HG in IDH1/2-mutant tumours.