Research Highlights in 2017

Activation of STAT3-coupled receptors along with TGF-β signaling are fundamental for Th17 cell differentiation both in vivo and in vitro. A recent paper shows that TGF-β signaling relieves SKI-mediated transcriptional repression of Rorc, the key regulator of the Th17 program.

Wild mice are genetically similar to laboratory mice, but have a distinct gut microbiota that protects from disease.

Two articles in Cell Research focus on the structure-function relationships in the shelterin complex that binds to telomeres and is essential for their stability and functions. These studies concerning both mammalian and Schizosaccharomyces pombe proteins reveal unexpected structural conservation of a motif called TRFH (Telomeric Repeat Factors Homology) domain between several subunits in these complexes, providing a rationale for further dissection of the role of telomeres in chromosome stability, aging and cancer, and encouraging us to revisit the evolution of telomere proteins.

Avian influenza A H7N9 viruses that emerged in China in 2013 have reappeared each year, causing more than 1 600 severe human infections. As these viruses have evolved in nature, they have gained some and can gain additional virulence determinants that enhance their risk for humans, underlining the urgent need to control and eradicate H7N9 viruses in China.

B cells undergo stringent selection in germinal centers (GCs) for expression of high-affinity antibodies, however, mechanisms of negative selection of low-affinity B cell clones remain elusive. A new study by Michel Nussenzweig's group published in Science leverages a new reporter system that marks pre-apoptotic GC B cells to dissect microanatomic regions of GCs and their role in affinity maturation.

Long-noncoding RNAs (lncRNAs) are emerging as important regulators of cellular processes, but few have been functionally characterized in host-pathogen interactions. A recent report in Science demonstrates a mechanistic role for a novel lncRNA in directly binding an essential metabolic enzyme, glutamic-oxaloacetic transaminase (GOT2); this interaction benefits viral replication via alteration of host metabolism.

Recently, ZATT (also known as ZNF451 or Zpf451) was reported by Schellenberg et al. to aid the removal of Topoisomerase II cleavage complexes by stimulating the phosphodiesterase activity of Tyrosyl DNA Phosphodiesterase 2. Although the full implication of this discovery is unknown, it will help us understand how cells respond to topoisomerase-induced genome damage and chemotherapeutic topoisomerase 'poisons'.

In an elegant publication in Cell Research, Tan and colleagues showed that ablation of PRRT2 in cerebellar granule cells is sufficient to induce paroxysmal kinesigenic dyskinesia. PRRT2 turns out to downregulate the presynaptic SNARE complex in granule cell axons, which in turn controls the activity patterns of Purkinje cells, the sole output of the cerebellar cortex.

In a paper recently published in Cell Research, Yu et al. identify two MAPK-related kinases, MAPK11 and HIPK3, as positive regulators of levels of mutant huntingtin protein, a toxic species highly involved in Huntington's disease (HD) pathology. The identification and validation of these kinases as therapeutic targets for knockdown in multiple relevant experimental model systems reveal novel potential approaches for treatment of HD.

Circular RNAs (circRNAs) are a novel class of RNA whose physiological function has yet to be investigated. A recent publication in Science provides the first evidence of the biological relevance of a circRNA in an in vivo model and unveils an unexpected twist on their crosstalk with miRNAs.

Intermittent fasting (IF) has been shown to promote metabolic health in several organisms. Two recent papers show that IF induces white adipose tissue beiging and increases thermogenesis, which improves metabolic health in mice.

In a recent paper published in Cell Research, a cryo-EM structure reveals the interface between DNA-PKcs and the Ku70/80:DNA complex, together forming the DNA-dependent protein kinase holoenzyme in non-homologous DNA end joining. Insight from this structure suggests how an allosteric rearrangement of DNA-PKcs driven by Ku70/80:DNA binding regulates kinase activity in this largest member of a family of structurally homologous phosphoinositide 3-kinase-related protein kinases that includes mTOR, ATR, and ATM.

In a recent paper published in Cell Research, Abdul-Ghani and colleagues show that the cytokine, cardiotrophin-1 (CT1), drives a protective form of reversible cardiac hypertrophy that acts through a nonapoptotic caspase-dependent mechanism. Since CT1 can be delivered as exogenous protein, these studies provide new biological insights and potential translational opportunities.

Type I interferon (IFN) signaling is critical for intracellular antimicrobial programmes, affecting both innate and adaptive immune responses. The paper recently published in Cell demonstrates a new regulatory mechanism of the type I IFN signaling pathway by histone-lysine N-methyltransferase SETD2.

New plant type (NPT) or ideal plant architecture (IPA) is an attractive way of increasing yield potential by promoting high resource use efficiency combined with better lodging resistance. In a recent paper in Cell Research, Wang et al. describe how a QTL they identified could bring about the desired NPT architecture by elucidating the role of its encoded gene in controlling the stability of IPA1/OsSPL14, a previously reported NPT protein, in the context of ubiquitination.

The plant hormone strigolactone (SL) is important for many processes in plants, but its molecular mode of action has been difficult to elucidate. A new discovery has identified the SPL transcription factor, IPA1, as a crucial component directly involved in SL signaling.

A recent study led by Professor Rob Martienssen in Cell showed that 3′-tRNA-derived small RNAs can suppress long terminal repeat retrotransposon activity in mammalian cells by mechanisms independent of DNA-associated epigenetic marks, suggesting how the genome may defend itself from retrotransposon invasion during epigenetic reprogramming.

SMADs are essential transcriptional effectors of transforming growth factor-β (TGFβ)/TGFβ-related signaling that underlies embryonic development and adult homeostasis. A recent study by Fang et al. in Cell Research adds to this biological complexity by demonstrating an atypical cytoplasmic role for SMAD5 in modulating the bioenergetic homeostasis (i.e., glycolysis and mitochondrial respiration) of cells in response to fluctuations in intracellular pH that is independent of receptor signaling.

Inflammasome sensors recognize pathogens and danger signals and assemble an immune signaling complex, which induces the secretion of pro-inflammatory cytokines IL-1β and IL-18, and pyroptosis. A new study published in Nature now describes a new inflammasome sensor NLRP9b in intestinal epithelial cells, which in concert with the RNA sensor DHX9, recognize short dsRNA from Rotavirus.

Adult mammalian hearts cannot repair by themselves after injury due to limited proliferation of cardiomyocytes; removal of cell cycle blocker and/or addition of drugs that boost proliferation of cardiomyocytes provide potential means to cardiac regeneration. Three publications that appeared recently in Nature and Cell Research now provide new hope to the treatment of heart injuries.