Retinal racemose hemangioma presenting with a chorioretinal anastomosis.

Purpose: To report a case of neovascular glaucoma in an 8-year-old male, secondary to a racemose hemangioma without associated intracranial arteriovenous malformation, highlighting the challenges in management and novel findings on optical coherence tomography angiography (OCTA).

Observations: An 8-year-old male initially presented with pain, redness, and blurred vision in the right eye. The patient was diagnosed with secondary neovascular glaucoma due to a racemose hemangioma.

Scalable biological signal recording in mammalian cells using Cas12a base editors.

Biological signal recording enables the study of molecular inputs experienced throughout cellular history. However, current methods are limited in their ability to scale up beyond a single signal in mammalian contexts. Here, we develop an approach using a hyper-efficient dCas12a base editor for multi-signal parallel recording in human cells.

Multiplexed genome regulation in vivo with hyper-efficient Cas12a.

Multiplexed modulation of endogenous genes is crucial for sophisticated gene therapy and cell engineering. CRISPR-Cas12a systems enable versatile multiple-genomic-loci targeting by processing numerous CRISPR RNAs (crRNAs) from a single transcript; however, their low efficiency has hindered in vivo applications. Through structure-guided protein engineering, we developed a hyper-efficient Lachnospiraceae bacterium Cas12a variant, termed hyperCas12a, with its catalytically dead version hyperdCas12a showing significantly enhanced efficacy for gene activation, particularly at low concentrations of crRNA.

Centromeres are maintained by fastening CENP-A to DNA and directing an arginine anchor-dependent nucleosome transition.

Maintaining centromere identity relies upon the persistence of the epigenetic mark provided by the histone H3 variant, centromere protein A (CENP-A), but the molecular mechanisms that underlie its remarkable stability remain unclear. Here, we define the contributions of each of the three candidate CENP-A nucleosome-binding domains (two on CENP-C and one on CENP-N) to CENP-A stability using gene replacement and rapid protein degradation. Surprisingly, the most conserved domain, the CENP-C motif, is dispensable.

A Dual Inhibitory Mechanism Sufficient to Maintain Cell-Cycle-Restricted CENP-A Assembly.

Chromatin featuring the H3 variant CENP-A at the centromere is critical for its mitotic function and epigenetic maintenance. Assembly of centromeric chromatin is restricted to G1 phase through inhibitory action of Cdk1/2 kinases in other phases of the cell cycle. Here, we identify the two key targets sufficient to maintain cell-cycle control of CENP-A assembly.

The CENP-L-N Complex Forms a Critical Node in an Integrated Meshwork of Interactions at the Centromere-Kinetochore Interface.

During mitosis, the macromolecular kinetochore complex assembles on the centromere to orchestrate chromosome segregation. The properties and architecture of the 16-subunit Constitutive Centromere-Associated Network (CCAN) that allow it to build a robust platform for kinetochore assembly are poorly understood. Here, we use inducible CRISPR knockouts and biochemical reconstitutions to define the interactions between the human CCAN proteins.

Chromosomes. CENP-C reshapes and stabilizes CENP-A nucleosomes at the centromere.

Inheritance of each chromosome depends upon its centromere. A histone H3 variant, centromere protein A (CENP-A), is essential for epigenetically marking centromere location. We find that CENP-A is quantitatively retained at the centromere upon which it is initially assembled.

Both tails and the centromere targeting domain of CENP-A are required for centromere establishment.

The centromere-defined by the presence of nucleosomes containing the histone H3 variant, CENP-A-is the chromosomal locus required for the accurate segregation of chromosomes during cell division. Although the sequence determinants of human CENP-A required to maintain a centromere were reported, those that are required for early steps in establishing a new centromere are unknown. In this paper, we used gain-of-function histone H3 chimeras containing various regions unique to CENP-A to investigate early events in centromere establishment.

Iron increases APP translation and amyloid-beta production in the retina.

Age-related macular degeneration (AMD) is the most common cause of blindness among older adults in developed countries, and retinal iron accumulation may exacerbate the disease. Iron can upregulate the production of amyloid precursor protein (APP). Since amyloid-β (Aβ), a byproduct of APP proteolysis, is found in drusen, the histopathological hallmark of AMD, we tested the role of iron in regulating APP and Aβ levels in the retinal pigment epithelial cell line ARPE-19.

Islet transplantation in type I diabetes mellitus.

For most patients with type I diabetes, insulin therapy and glucose monitoring are sufficient to maintain glycemic control. However, hypoglycemia is a potentially lethal side effect of insulin treatment in patients who are glycemically labile or have hypoglycemia-associated autonomic failure [1]. For those patients, an alternative therapy is beta cell replacement via pancreas or islet transplantation.

Aph-1 associates directly with full-length and C-terminal fragments of gamma-secretase substrates.

Gamma-secretase is a ubiquitous, multiprotein enzyme composed of presenilin, nicastrin, Aph-1, and Pen-2. It mediates the intramembrane proteolysis of many type 1 proteins, plays an essential role in numerous signaling pathways, and helps drive the pathogenesis of Alzheimer disease by excising the hydrophobic, aggregation-prone amyloid beta-peptide from the beta-amyloid precursor protein. A central unresolved question is how its many substrates bind and enter the gamma-secretase complex.

RNA stability regulates differential expression of the metastasis protein, osteopontin, in hepatocellular cancer.

Background: Osteopontin (OPN) is a potential therapeutic target in hepatocellular carcinoma (HCC), because it is a critical mediator of metastatic function. The molecular mechanisms that determine expression of OPN in HCC, however, are unknown. In this study, we examine differential OPN expression in the 2 HCC cell lines: HepG2 and Hep3B.

Little science, big science: strategies for research portfolio selection in academic surgery departments.

Objective: To evaluate National Institutes of Health (NIH) funding for academic surgery departments and to determine whether optimal portfolio strategies exist to maximize this funding.

Summary Background Data: The NIH budget is expected to be relatively stable in the foreseeable future, with a modest 0.7% increase from 2005 to 2006.

Stat1 acetylation inhibits inducible nitric oxide synthase expression in interferon-gamma-treated RAW264.7 murine macrophages.

Background: We hypothesized that acetylation of the Stat1 regulates interferon-gamma (IFN-gamma) mediated macrophage expression of inducible nitric oxide synthase (iNOS).

Methods: RAW 264.7 iNOS expression was induced with IFN-gamma.