Loss-of-function mutations in a single allele of the gene encoding DEP domain–containing 5 protein (DEPDC5) are commonly linked to familial focal epilepsy with variable foci; however, a subset of patients presents with focal cortical dysplasia that is proposed to result from a second-hit somatic mutation. In this issue of the JCI, Ribierre and colleagues provide several lines of evidence to support second-hit DEPDC5 mutations in this disorder. Moreover, the authors use in vivo, in utero electroporation combined with CRISPR-Cas9 technology to generate a murine model of the disease that recapitulates human manifestations, including cortical dysplasia–like changes, focal seizures, and sudden unexpected death. This study provides important insights into familial focal epilepsy and provides a preclinical model for evaluating potential therapies.
Matthew P. Anderson
The last decade has led to a significant advance in our knowledge of HIV-1 latency and immunity. However, we are still not close to finding a cure for HIV-1. Although combination antiretroviral therapy (cART) has led to increased survival, almost close to that of the general population, it is still not curative. In the current issue of the JCI, Wu et al. studied the prophylactic and therapeutic potential of an engineered tandem bispecific broadly neutralizing antibody (bs-bnAb), BiIA-SG. This bnAb’s breadth and potency were highly effective in protection and treatment settings, as measured by complete viremia control following direct infusion, as well as elimination of infected cells and delay in viral rebound when delivered with a recombinant vector. These observations underscore the need for the clinical development of BiIA-SG for the prevention of HIV-1.
Poly(ADP-ribose) polymerase inhibitors (PARPis) are DNA-damaging agents that trap PARP-DNA complexes and interfere with DNA replication. Three PARPis — olaparib, niraparib, and rucaparib — were recently approved by the FDA for the treatment of breast and ovarian cancers. These PARPis, along with 2 others (talazoparib and veliparib), are being evaluated for their potential to treat additional malignancies, including prostate cancers. While lack of PARP-1 confers high resistance to PARPis, it has not been established whether or not the levels of PARP-1 directly correlate with tumor response. In this issue of the JCI, Makvandi and coworkers describe an approach to address this question using [18F]FluorThanatrace, an [18F]-labeled PARP-1 inhibitor, for PET. The tracer was taken up by patient tumor tissue and appeared to differentiate levels of PARP-1 expression; however, future studies should be aimed at determining if this tracer can be used to stratify patient response to PARPi therapy.
Anish Thomas, Junko Murai, Yves Pommier
The identity and function of the fibroblast, a highly prevalent cell type in the heart, have remained poorly defined. Recent faithful genetic lineage–tracing studies revealed that during development, the cardiac fibroblasts are derived from the epicardium and the endothelium, whereas in the adult heart, they constitute the cardiac injury–responsive resident fibroblast. In the current issue of the JCI, Molkentin and colleagues decipher the time course and mechanism of the fibroblast in response to myocardial infarction (MI). The model they propose is surprisingly simple and clear. It consists of three major phases. First, fibroblasts in the ischemic area die. Second, surrounding fibroblasts proliferate and migrate into the spaces created by dying cardiomyocytes over a few days. The new fibroblasts in the scar are activated and adopt a smooth muscle actin– and periostin-positive “myofibroblast” phenotype, which appears to last as long as the scar is not mature (~10 days after MI). In the third phase, initially proliferating myofibroblasts lose smooth muscle actin expression and convert to a nonproliferating, matrix-producing phenotype with a newly acquired tendon gene signature. Interestingly, this state appears to differ from that of quiescent fibroblasts in the uninjured heart, as it is resistant to proliferative stimuli. These cells are therefore termed “matrifibrocytes,” a novel category whose study will certainly further advance the field.
Current therapies for pulmonary arterial hypertension (PAH) provide symptomatic relief and improve prognosis but fall short of improving long-term survival. There is emerging evidence for a role of inflammatory mediators, primarily IL-6, in the pathogenesis of PAH. However, the mechanisms by which IL-6 potentially affects PAH are unknown. In this issue of the JCI, Tamura, Phan, and colleagues identified ectopic upregulation of the membrane-bound IL-6 receptor (IL6R), indicating classical IL-6 signaling in the smooth muscle layer of remodeled vessels in human and experimental PAH. They performed a series of in vitro and in vivo experiments that provide deeper insights into the mechanisms of classical IL-6 signaling and propose interventions directed against IL6R as a potential therapeutic strategy for PAH.
Soni Savai Pullamsetti, Werner Seeger, Rajkumar Savai
Rasmussen’s encephalitis (RE) is a neuroinflammatory disease that typically affects only one hemisphere of the brain, resulting in severe seizures. Sixty years after the disease was first described, the preferred and best treatment option for RE is grotesque and involves removing a hemisphere of the brain (hemispherectomy); therefore, a better understanding of this seizure disorder may provide additional, less invasive therapeutic options. In this issue of the JCI, Carmant and colleagues have developed an animal model of this focal seizure disorder. The model provides experimental insights into the pathogenesis of RE and potential new treatments for this disease.
Inheritance of the E4 allele of the apolipoprotein E gene (APOE4) substantially increases the risk of developing late-onset Alzheimer disease (AD). A large body of evidence has firmly established a role for apoE in modulating the risk of developing the amyloid plaque pathology that is pathognomonic for AD. In this issue of the JCI, Liao and colleagues discovered that antibodies against a nonlipidated form of apoE4 are highly effective in delaying the deposition of amyloid β (Aβ) peptides in mouse models of AD pathology. Using a combination of passive immunization and viral-mediated expression of recombinant antibodies, the authors show that Fc receptor–mediated clearance of the nonlipidated apoE4 was critical in delaying Aβ deposition. Collectively, this study identifies a new therapeutic target that could be exploited to prevent, or possibly reverse, the Aβ pathology of AD.
David R. Borchelt
Malaria, caused by mosquito-transmitted Plasmodium parasites, continues to take a major toll on global health. The development of drugs and vaccines that reduce malaria transmission from humans back to mosquitos could contribute to the control and eventual eradication of malaria, but research models for the early clinical evaluation of candidate interventions are lacking. In this issue of the JCI, Collins and colleagues report the successful transmission of Plasmodium falciparum parasites from humans to mosquitoes during controlled human malaria infection, thus providing a potential tool to accelerate the development of much needed transmission-blocking drugs and vaccines.
Kazutoyo Miura, Peter D. Crompton
As oncogenes drive carcinogenesis and promote cancer cell survival, they are highly attractive therapeutic targets, and oncogene-targeting small molecules have achieved some clinical success. While many oncogenes are presently considered to be “druggable,” tumors often acquire treatment resistance, and patients are rarely cured in response to oncogene-specific treatment. In this issue of the JCI, Veatch and colleagues describe a patient with metastatic acral melanoma who experienced a complete tumor response following infusion of tumor-infiltrating T cells that targeted multiple tumor antigens, including a BRAFV600E driver mutation. T cells genetically engineered to express an anti-BRAFV600E T cell receptor (TCR) from the patient demonstrated recognition of an epitope that spanned the BRAFV600E mutation. These findings suggest that BRAFV600E might be targeted therapeutically with adoptive transfer of anti-BRAFV600E T cells. This research supports the emerging therapeutic paradigm of targeting oncogenic drivers with T cell immunotherapy.
Christian S. Hinrichs
Oncolytic viruses (OVs) are a versatile new class of therapeutic agents based on native or genetically modified viruses that selectively replicate in tumor cells and can express therapeutic transgenes designed to target cells within the tumor microenvironment and/or host immunity. To date, however, confirmation of the underlying mechanism of action and an understanding of innate and acquired drug resistance for most OVs have been limited. In this issue of the JCI, Zamarin et al. report a comprehensive analysis of an oncolytic Newcastle disease virus (NDV) using both murine melanoma tumor models and human tumor explants to explore how the virus promotes tumor eradication and details of the mechanisms involved. These findings have implications for the optimization of oncolytic immunotherapy, at least that based on NDV, and further confirm that specific combinatorial approaches are promising for clinical development.
Praveen K. Bommareddy, Howard L. Kaufman
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