Angiotensin Receptor-Neprilysin Inhibition (Sacubitril/Valsartan) Reduces Structural Arterial Stiffness in Middle-Aged Mice.

BACKGROUND: Increasing arterial stiffness is a prominent feature of the aging cardiovascular system. Arterial stiffening leads to fundamental alterations in central hemodynamics with widespread detrimental implications for organ function resulting in significant morbidity and death, and specific therapies to address the underlying age-related structural arterial remodeling remain elusive. The present study investigates the potential of the recently clinically available dual angiotensin receptor-neprilysin inhibitor (ARNI) sacubitril/valsartan (LCZ696) to counteract age-related arterial fibrotic remodeling and stiffening in 1-year-old mice. METHODS AND RESULTS: Treatment of in 1-year-old mice with ARNI (sacubitril/valsartan), in contrast to angiotensin receptor blocker monotherapy (valsartan) and vehicle treatment (controls), significantly decreases structural aortic stiffness (as measured by in vivo pulse-wave velocity and ex vivo aortic pressure myography). This phenomenon appears, at least partly, independent of (indirect) blood pressure effects and may be related to a direct antifibrotic interference with aortic smooth muscle cell collagen production. Furthermore, we find aortic remodeling and destiffening due to ARNI treatment to be associated with improved parameters of cardiac diastolic function in aged mice. CONCLUSIONS: This study provides preclinical mechanistic evidence indicating that ARNI-based interventions may counteract age-related arterial stiffening and may therefore be further investigated as a promising strategy to improve cardiovascular outcomes in the elderly.

Reproducible and scalable differentiation of highly pure cortical neurons from human induced pluripotent stem cells.

Human-induced-pluripotent-stem-cell (hiPSC)-derived neurons are valuable for investigating brain physiology and disease. Here, we present a protocol to differentiate hiPSCs into cortical neurons with high yield and purity. We describe neural induction via dual-SMAD inhibition, followed by spot-based differentiation to provide high quantities of neural precursors. We detail their enrichment, expansion, and purification to avoid unwanted cell fates and provide optimal conditions for neural rosette proliferation. These differentiated neurons are suitable for drug testing and co-culture studies. For complete details on the use and execution of this protocol, please refer to Paquet et al.1 and Weisheit et al..2.

Unresolved Issues in RNA Therapeutics in Vascular Diseases With a Focus on Aneurysm Disease.

New technologies have greatly shaped the scientific and medical landscape within the last years. The unprecedented expansion of data and information on RNA biology has led to the discovery of new RNA classes with unique functions and unexpected modifications. Today, the biggest challenge is to transfer the large number of findings in basic RNA biology into corresponding clinical RNA-based therapeutics. Lately, this research begins to yield positive outcomes. RNA drugs advance to the final phases of clinical trials or even receive FDA approval. Furthermore, the introduction of the RNA-guided gene-editing technology CRISPR and advances in the delivery of messenger RNAs have triggered a major progression in the field of RNA-therapeutics. Especially short interfering RNAs and antisense oligonucleotides are promising examples for novel categories of therapeutics. However, several issues need to be addressed including intracellular delivery, toxicity, and immune responses before utilizing RNAs in a clinical setting. In this review, we provide an overview on opportunities and challenges for clinical translation of RNA-based therapeutics, with an emphasis on advances in novel delivery technologies and abdominal aortic aneurysm disease where non-coding RNAs have been shown to play a crucial regulatory role.

MicroRNA miR-29b regulates diabetic aortic remodeling and stiffening.

Patients with type 2 diabetes (T2D) are threatened by excessive cardiovascular morbidity and mortality. While accelerated arterial stiffening may represent a critical mechanistic factor driving cardiovascular risk in T2D, specific therapies to contain the underlying diabetic arterial remodeling have been elusive. The present translational study investigates the role of microRNA-29b (miR-29b) as a driver and therapeutic target of diabetic aortic remodeling and stiffening. Using a murine model (db/db mice), as well as human aortic tissue samples, we find that diabetic aortic remodeling and stiffening is associated with medial fibrosis, as well as fragmentation of aortic elastic layers. miR-29b is significantly downregulated in T2D and miR-29b repression is sufficient to induce both aortic medial fibrosis and elastin breakdown through upregulation of its direct target genes COL1A1 and MMP2 thereby increasing aortic stiffness. Moreover, antioxidant treatment restores aortic miR-29b levels and counteracts diabetic aortic remodeling. Concluding, we identify miR-29b as a comprehensive-and therefore powerful-regulator of aortic remodeling and stiffening in T2D that moreover qualifies as a (redox-sensitive) target for therapeutic intervention.

Detection of Deleterious On-Target Effects after HDR-Mediated CRISPR Editing.

CRISPR genome editing is a promising tool for translational research but can cause undesired editing outcomes, both on target at the edited locus and off target at other genomic loci. Here, we investigate the occurrence of deleterious on-target effects (OnTEs) in human stem cells after insertion of disease-related mutations by homology-directed repair (HDR) and gene editing using non-homologous end joining (NHEJ). We identify large, mono-allelic genomic deletions and loss-of-heterozygosity escaping standard quality controls in up to 40% of edited clones. To reliably detect such events, we describe simple, low-cost, and broadly applicable quantitative genotyping PCR (qgPCR) and single-nucleotide polymorphism (SNP) genotyping-based tools and suggest their usage as additional quality controls after editing. This will help to ensure the integrity of edited loci and increase the reliability of CRISPR editing.

Neurodegeneration in a dish: advancing human stem-cell-based models of Alzheimer's disease.

Induced pluripotent stem-cell-based models enable investigation of pathomechanisms in disease-relevant human brain cell types and therefore offer great potential for mechanistic and translational studies on neurodegenerative disorders, such as Alzheimer's disease (AD). While current AD models allow analysis of early disease phenotypes including Aß accumulation and Tau hyperphosphorylation, they still fail to fully recapitulate later hallmarks such as protein aggregation and neurodegeneration. This impedes the identification of pathomechanisms and novel therapeutic targets. We discuss strategies to overcome these drawbacks and optimize physiological properties and translational potential of iPSC-based models by improving culture formats, increasing cellular diversity, applying genome editing, and implementing maturation and ageing paradigms.

Expression of checkpoint molecules on myeloid-derived suppressor cells.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous cell population expanded in cancer, infection and autoimmunity capable of suppressing T-cell functions. Checkpoint inhibitors have emerged as a key therapeutic strategy in immune-oncology. While checkpoint molecules were initially associated with T cell functions, recent evidence suggests a broader expression and function in innate myeloid cells. Previous studies provided first evidence for a potential role for checkpoints on MDSCs, yet the human relevance remained poorly understood. Therefore, we investigated the expression and functional relevance of checkpoint molecules in human MDSC-T-cell interactions. Our studies demonstrate that programmed death-ligand 1 (PD-L1) is expressed on granulocytic MDSCs upon co-culture with T cells. Transwell experiments showed that cell-to-cell contact was required for MDSC-T-cell interactions and antibody blocking studies showed that targeting PD-L1 partially impaired MDSC-mediated T-cell suppression. Collectively, these studies suggest a role for PD-L1 in human MDSC function and thereby expand the functionality of this checkpoint beyond T cells, which could pave the way for further understanding and therapeutic targeting of PD-1/PD-L1 in innate immune-mediated diseases.