CaMK4 drives podocyte injury

Podocyte dysfunction is a hallmark of kidney injury and occurs in both autoimmune and nonautoimmune renal diseases. Calcium signaling underlies podocyte injury; however, the factors that promote calcium signaling in podocytes in response to injury are not fully understood. In this episode, George Tsokos and colleagues demonstrate that Ca²⁺/calmodulin–dependent kinase 4 (CaMK4) is increased in podocytes from patients with lupus nephritis and focal segmental glomerulosclerosis and in mouse models of lupus and kidney injury. Moreover, administration of a CaMK4 inhibitor prevented nephritis in lupus-prone mice and ameliorated podocyte damage in mice with kidney injury. Togeither, this study identifies CaMK4 activation as a driver of podocyte dysfunction and suggests CaMK4 inhibition be further explored for treating podocytopathies.

JCI’s Conversations with Giants in Medicine: Cornelia Bargmann

How are behavioral decisions modified by context and experience? Cornelia Bargmann of Rockefeller University has made this her life’s work, exploring the intersection between genes, the environment, and the nervous system in the roundworm, C. elegans. Bargmann is also seeking to help cure, manage, and prevent all disease by the year 2100 by serving as Head of Science for the Chan Zuckerberg Initiative.

Altered abiraterone metabolism in individuals with HSD3B1 variant

Prostate cancer is driven by stimulation of the androgen receptor (AR) with testosterone and the potent metabolite 5α-dihydrotestosterone; therefore, androgen deprivation, via medical or surgical castration, is the standard treatment for disease. Unfortunately, extragonadal androgen production often increases in response to castration. In particular, patients with a 1245A>C variant of HSD3B1, which encodes 3β-hydroxysteroid dehydrogenase-1(3βHSD1), exhibit rapid development of castration resistance. In this episode, Nima Sharifi and colleagues evaluated the effect of the HSD3B1(1245C) variant on metabolism of abiraterone, a drug used to block extragonadal androgens. Compared to those with HSD3B1(1245A), those with the mutation had increased levels of the metabolite 3-keto-5α-abiraterone, which has androgenic activity. These results support further investigation into the clinical consequences of increased 3-keto-5α-abiraterone in patients harboring HSD3B1(1245C).

JAK inhibitor treatment shows benefit for patients with interferonopathies

Patients with IFN-mediated autoinflammatory diseases, such as CANDLE and SAVI, present with a variety of severe manifestations, including fever and inflammatory organ damage, and have a high mortality rate. Many of these patients fail to respond to IL-1-blocking agents or other approved therapies for autoinflammatory disease.  In this episode, Gina A. Montealegre Sanchez, Raphaela Goldbach-Mansky, and colleagues present the results of compassionate use, dose-escalation study of the JAK1/2 inhibitor baricitinib in small cohort of patients with interferonopathies. Baricitinib treatment reduced clinical manifestations and inflammatory biomarkers in most patients with few adverse effects, supporting the use of JAK inhibitors for this subtype of autoinflammatory disease.

REV-ERBα controls the clock in the lung

There is a strong variation in pulmonary inflammation depending on the time of day. Airway epithelial cells have been shown to mediate rhythmic inflammatory responses, and loss of the central clock component BMAL1 in airway epithelium augments inflammation. It is not clear how BMAL1 regulates lung inflammation; however, REV-ERB transcription factors, have been proposed to regulate immune function downstream of BMAL1. In this episode, David Ray, Marie Pariollaud and colleagues provide evidence that REV-ERBα couples the pulmonary clock to innate immunity. Inflammatory stimuli were shown to promote REV-ERBα degradation, and complete lack of REV-ERBα further enhanced inflammation in the lungs in following inflammatory challenge. Together, these results identify REV-ERBα as a regulator of rhythmic inflammatory responses in the lung and provide rationale for further exploration of REV-ERBα as a target for inflammatory disease.