Treatment with RNase alleviates brain injury but not neuroinflammation in neonatal hypoxia/ischemia

There is a need for new treatments to reduce brain injuries derived from neonatal hypoxia/ischemia. The only viable option used in the clinic today in infants born at term is therapeutic hypothermia, which has a limited efficacy. Treatments with exogenous RNase have shown great promise in a range of different adult animal models including stroke, ischemia/reperfusion injury, or experimental heart transplantation, often by conferring vascular protective and anti-inflammatory effects. However, any neuroprotective function of RNase treatment in the neonate remains unknown. Using a well-established model of neonatal hypoxic/ischemic brain injury, we evaluated the influence of RNase treatment on RNase activity, gray and white matter tissue loss, blood-brain barrier function, as well as levels and expression of inflammatory cytokines in the brain up to 6 h after the injury using multiplex immunoassay and RT-PCR. Intraperitoneal treatment with RNase increased RNase activity in both plasma and cerebropinal fluids. The RNase treatment resulted in a reduction of brain tissue loss but did not affect the blood-brain barrier function and had only a minor modulatory effect on the inflammatory response. It is concluded that RNase treatment may be promising as a neuroprotective regimen, whereas the mechanistic effects of this treatment appear to be different in the neonate compared to the adult and need further investigation.

Acidosis-mediated increase in IFN-γ-induced PD-L1 expression on cancer cells as an immune escape mechanism in solid tumors

Immune checkpoint inhibitors have revolutionized cancer therapy, yet the efficacy of these treatments is often limited by the heterogeneous and hypoxic tumor microenvironment (TME) of solid tumors. In the TME, programmed death-ligand 1 (PD-L1) expression on cancer cells is mainly regulated by Interferon-gamma (IFN-γ), which induces T cell exhaustion and enables tumor immune evasion. In this study, we demonstrate that acidosis, a common characteristic of solid tumors, significantly increases IFN-γ-induced PD-L1 expression on aggressive cancer cells, thus promoting immune escape. Using preclinical models, we found that acidosis enhances the genomic expression and phosphorylation of signal transducer and activator of transcription 1 (STAT1), and the translation of STAT1 mRNA by eukaryotic initiation factor 4F (elF4F), resulting in an increased PD-L1 expression. We observed this effect in murine and human anti-PD-L1-responsive tumor cell lines, but not in anti-PD-L1-nonresponsive tumor cell lines. In vivo studies fully validated our in vitro findings and revealed that neutralizing the acidic extracellular tumor pH by sodium bicarbonate treatment suppresses IFN-γ-induced PD-L1 expression and promotes immune cell infiltration in responsive tumors and thus reduces tumor growth. However, this effect was not observed in anti-PD-L1-nonresponsive tumors. In vivo experiments in tumor-bearing IFN-γ-/- mice validated the dependency on immune cell-derived IFN-γ for acidosis-mediated cancer cell PD-L1 induction and tumor immune escape. Thus, acidosis and IFN-γ-induced elevation of PD-L1 expression on cancer cells represent a previously unknown immune escape mechanism that may serve as a novel biomarker for anti-PD-L1/PD-1 treatment response. These findings have important implications for the development of new strategies to enhance the efficacy of immunotherapy in cancer patients.

Treatment with Anti-HER2 Chimeric Antigen Receptor Tumor-Infiltrating Lymphocytes (CAR-TILs) Is Safe and Associated with Antitumor Efficacy in Mice and Companion Dogs

Patients with metastatic melanoma have a historically poor prognosis, but recent advances in treatment options, including targeted therapy and immunotherapy, have drastically improved the outcomes for some of these patients. However, not all patients respond to available treatments, and around 50% of patients with metastatic cutaneous melanoma and almost all patients with metastases of uveal melanoma die of their disease. Thus, there is a need for novel treatment strategies for patients with melanoma that do not benefit from the available therapies. Chimeric antigen receptor-expressing T (CAR-T) cells are largely unexplored in melanoma. Traditionally, CAR-T cells have been produced by transducing blood-derived T cells with a virus expressing CAR. However, tumor-infiltrating lymphocytes (TILs) can also be engineered to express CAR, and such CAR-TILs could be dual-targeting. To this end, tumor samples and autologous TILs from metastasized human uveal and cutaneous melanoma were expanded in vitro and transduced with a lentiviral vector encoding an anti-HER2 CAR construct. When infused into patient-derived xenograft (PDX) mouse models carrying autologous tumors, CAR-TILs were able to eradicate melanoma, even in the absence of antigen presentation by HLA. To advance this concept to the clinic and assess its safety in an immune-competent and human-patient-like setting, we treated four companion dogs with autologous anti-HER2 CAR-TILs. We found that these cells were tolerable and showed signs of anti-tumor activity. Taken together, CAR-TIL therapy is a promising avenue for broadening the tumor-targeting capacity of TILs in patients with checkpoint immunotherapy-resistant melanoma.

Characterization of Biostable Atomic Layer Deposited (ALD) Multilayer Passivation Coatings for Active Implants

The next generation of flexible, electrically active implants, such as brain implants or retina chips require a flexible, biostable as well as biocompatible passivation, ensuring a degradation-free usage for long time periods on the order of several years. Until today, these passivations are prepared mostly by polyimides or parylene, both of which are water vapor permeable to a certain degree. To remedy this deficiency, Atomic Layer Deposited (ALD) thin films are characterized regarding their electrical passivating features under conditions of accelerated aging, such as elevated temperatures in a liquid environment. The initial electrical passivation by various ALD deposited multilayers, combining alternating thin Al₂O₃ and TiO₂ layers is the goal of this research as well as the stability of these layers under induced degradation. Such layers, in combination with a parylene passivation, would ensure a water vapor impermeable and biocompatible coating.

Evaluation of adhesion promoters for Parylene C on gold metallization

Delamination of thin film polymeric coatings from metallization layers is a common cause of failure in biomedical implants. To address the problem, different adhesion promotion techniques can be applied which include surface pre-treatment with oxygen and argon plasma and the use of different adhesion promoters. In this paper the applicability of titanium (Ti), silicon oxide (SiOx), diamond-like carbon (DLC), tetramethylsilane (TMS) and aluminium oxide (AlOx) as adhesion promoters is evaluated. A cross cut, peel and scratch test are used to qualify and quantify the adhesion before and after storage in phosphate buffered saline (PBS) for 48 hours at a temperature of 37 °C. Promising results could be achieved by a combination of Ti and DLC as well as by AlOx.

Patch-clamping of primary cardiac cells with micro-openings in polyimide films

Patch-clamping is a powerful method for investigating the function and regulation of ionic channels. Currently, great efforts are being made to automate this method. As a step towards this goal, the feasibility of patch-clamping primary cells with a microscopic opening in a planar substrate was tested. Using standard microfabrication and ion beam technology, small-diameter openings (2 and 4 microm) were formed in polyimide films (thickness 6.5 microm). Single cells (sheep Purkinje heart cells, Chinese hamster ovary cells) in a suspension were positioned on top of the opening and sucked towards the opening to improve adhesion of the cell to the planar substrate, hence increasing the seal resistance. Voltage/current measurements yielded a median seal resistance of 1.3 Mohms with 4 microm openings (n=24) and 26.0 Mohms with 2 microm openings (n = 75), respectively. With 2 microm openings, successful loose-patch recordings of TTX-sensitive inward currents and action potentials in sheep Purkinje heart cells (n = 18) were made. In rare cases, gigaseals (n = 4) were also measured, and a whole-cell configuration (n = 1) could be established. It was concluded that the simple planar patch approach is suitable for automated loose-patch recordings from cells in suspension but will hardly be suitable for high-throughput whole-cell patch-clamping with high-resistance seals.

Electrical properties of a light-addressable microelectrode chip with high electrode density for extracellular stimulation and recording of excitable cells

A light-addressable microelectrode chip with 3600 TiN electrodes was fabricated. Amorphous silicon (a-Si:H) serves as a photo conductor. The electrodes on the chip are addressed by a laser spot and electrical properties of the system are determined. DC measurements show a dark to bright dynamic of 10(6)-10(7). The AC impedance dynamic @ 1 kHz/100 mV and thus the signal-to-noise-ratio is determined to 60. This value is quite sufficient for electrophysiological measurements. For the first time, recordings from cardiac myocytes are reported using the principle of light-addressing. Measurements were done with a standard laser scan microscope (Zeiss LSM 410).