Collective cell migration in epithelia relies on <i>cell intercalation</i>: a local remodeling of the cellular network that allows neighboring cells to swap their positions. Unlike foams and passive cellular fluid, in epithelial intercalation, these rearrangements crucially depend on activity. During these processes, the local geometry of the network and the contractile forces generated therein conspire to produce a burst of remodeling events, which collectively give rise to a vortical flow at the mesoscopic length scale. In this article, we formulate a continuum theory of the mechanism driving this process, built upon recent advances toward understanding the hexatic (i.e., sixfold ordered) structure of epithelial layers. Using a combination of active hydrodynamics and cell-resolved numerical simulations, we demonstrate that cell intercalation takes place via the unbinding of topological defects, naturally initiated by fluctuations and whose late-times dynamics is governed by the interplay between passive attractive forces and active self-propulsion. Our approach sheds light on the structure of the cellular forces driving collective migration in epithelia and provides an explanation of the observed extensile activity of in vitro epithelial layers.
Science Journals
Gene expression patterns in the inner ear put an old question about structures called kinocilia back in motion.
Taste sensation plays a crucial role in shaping feeding behavior and is intricately influenced by internal states like hunger or satiety. Despite the identification of numerous neural substrates regulating feeding behavior, the central neural substrate that linked energy-sensing and taste sensation remained elusive. Here, we identified a novel neural circuitry that could directly sense internal energy state and modulate sweet sensation in the <i>Drosophila</i> brain. Specifically, a subset of neuropeptidergic neurons expressing hugin directly detected elevated levels of circulating glucose via glucose transporter Glut1 and ATP-sensitive potassium channels. Upon activation, these neurons released hugin peptide and activated downstream Allatostatin A (AstA)<sup>+</sup> neurons via its cognate receptor PK2-R1. Subsequently, the activation of AstA<sup>+</sup> neurons then directly inhibited sweet sensation via AstA peptide and its cognate receptor AstA-R1 expressed in sweet-sensing Gr5a<sup>+</sup> neurons. We also showed that Neuromedin U (NMU), the mammalian homolog of fly hugin, served as an energy sensor to suppress sweet sensation. Therefore, these data identify hugin<sup>+</sup> neuron as a glucose-responsive central energy-sensing module that modulates sweet sensation across species.
Mitochondrial electron transport flavoprotein (ETF) insufficiency causes metabolic diseases known as a multiple acyl-CoA dehydrogenase deficiency (MADD). In contrast to muscle, ETFDH is a non-essential gene in acute lymphoblastic leukemia NALM6 cells, and its expression is reduced across human cancers. In various human cancer cell lines and mouse models, ETF insufficiency caused by decreased ETFDH expression limits flexibility of OXPHOS fuel utilisation but paradoxically increases bioenergetics and accelerates neoplastic growth via activation of the mTORC1/BCL-6/4E-BP1 axis. Collectively, these findings reveal that while ETF insufficiency is rare and has detrimental effects in non-malignant tissues, it is common in neoplasia, where ETFDH downregulation leads to bioenergetic and signaling reprogramming that accelerates neoplastic growth.
Plants utilize receptor-like proteins and receptor-like kinases (RLPs/RLKs) to perceive and respond to a wide variety of invading pathogens and insect herbivores. While the strategies employed by microbial pathogens to suppress plant immunity have been well characterized, it remains unclear how herbivorous insects counteract receptor-mediated defenses. Here, we show that salivary effectors evolve independently in whiteflies and planthoppers to dampen RLP4-mediated plant immunity. RLP4, as a leucine-rich repeat RLP (LRR-RLP), confers plant resistance against herbivorous insects by forming the RLP4/SOBIR1 complexes. In the whitefly <i>Bemisia tabaci</i>, BtRDP, the Aleyrodidae-specific salivary sheath protein, interacts with RLP4 from multiple plant species and promotes its ubiquitin-dependent degradation. Overexpression of NtRLP4 in transgenic plants exerts a detrimental effect on <i>B. tabaci</i> by exploiting the crosstalk between the salicylic acid and jasmonic acid pathways. Conversely, overexpression of BtRDP or silencing of NtRLP4 effectively alleviates such negative effects. In planthopper <i>Nilaparvata lugens</i>, the Delphacidae-restricted salivary protein NlSP104 also targets and promotes the degradation of OsRLP4 from rice plants. These findings reveal convergent evolution of salivary proteins in insects and underscore the complex interactions between plants and herbivorous insects.
Eyes provide opportunities to understand the function, design, development, and evolution of elaborate sense organs. We take a new cost–benefit approach to understanding eye design by considering that optics and photoreceptors compete for the resources invested in an integrated system. We investigate this competition theoretically and empirically using a new measure of cost, specific volume. This common currency for optics and photoreceptors relates investments to image quality via geometrical, optical, and physiological constraints. By covering the morphospace of an eye of given type and cost, we model how trading optics against photoreceptors changes information capacity. In apposition compound eyes and simple eyes, an optimum configuration maximises efficiency. Efficiency requires heavy investment in photoreceptors and depends on photoreceptor energy consumption. Optimum information capacities and efficiencies scale non-linearly with total investment. Diurnal insects’ apposition eyes follow trends that promote efficiency: photoreceptor arrays take 40–80% of total specific volume, photoreceptor length increases systematically with spatial resolution, and photoreceptors are exceptionally long. Thus, competition between optics and photoreceptors shapes eye design, and matching investments in optics and photoreceptors to improve efficiency is a design principle. Our new methodology can be developed to view the adaptive radiation of eyes through a cost–benefit lens.
<p>by Xiaojia Zhu, Rui Bi, Haotian Yan, Qiyu Wang, Lin Li, Hongli Li, Long-Bao Lv, Cirong Liu, Yong-Gang Yao</p>
The tree shrew (<i>Tupaia belangeri</i>), phylogenetically proximal to primates, serves as a critical model for evolutionary neurobiology and disease mechanisms. High-resolution MRI provides a unique opportunity to refine its neuroanatomical architecture and facilitate cross-species comparisons. Here, we present a comprehensive, ultra-high-resolution (9.4T) MRI atlas of the tree shrew brain, integrating structural and diffusion imaging to resolve fine-scale anatomical features and whole-brain connectivity gradients. Our comparative analysis characterizes the tree shrew as a distinct evolutionary mosaic: the cerebellum exhibits pronounced volumetric expansion and connectivity gradients recapitulating those of primates, whereas the hippocampus retains rodent-like architectural scaling yet preserves evolutionarily conserved longitudinal functional axes. Moving beyond these regional adaptations, we uncovered a universal organizational principle: geometry–gradient coupling (GGC)—the fundamental constraint of brain shape on functional organization. By systematically linking geometric eigenmodes to connectivity gradients across diverse species (from mice to humans), we demonstrate that despite dramatic morphological divergence, the spatial alignment between brain geometry and functional organization remains evolutionarily invariant. Collectively, these results establish the tree shrew as a pivotal phylogenetic bridge and provide a neuroanatomical benchmark for deciphering the interplay between structural diversity and universal biophysical constraints.
<p>by Damian Koevoet, Dirk Van Moorselaar, Edward Awh, Stefan Van der Stigchel</p>
Visual selection is often conceptualized as emerging from goal-, stimulus- and history-driven processes within spatial priority maps. Although extensive work detailed the interplay between goal- and stimulus-driven selection, it is largely unknown how goal- and history-driven processes jointly drive selection. While persistent neural firing likely underlies goal-driven selection, it is generally assumed that activity-silent mechanisms effectuate history-driven selection. Due to these different underlying neural mechanisms, simultaneously tracking goal- and history-driven influences neurally has proven difficult. We here employed EEG decoding techniques to simultaneously track and compare goal- and history-driven influences on search. We first established a history-driven signal: Neural decoding closely tracked the target location from the preceding trial. We further demonstrated simultaneous, distinct neural representations of the current and preceding target locations. Strikingly, even when participants attended an upcoming target location before search could commence, prior target locations were reactivated. Our results show that past experiences are reactivated in an inflexible fashion, and do so even when prior targets are completely task-irrelevant. Together, we demonstrate that goal- and history-driven selection are neurally distinct, and reveal that both influences are represented in parallel.
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026. SignificanceThis study uncovers a mechanism by which a host-derived pseudogene RNA regulates innate immunity and highlights its clinicopathological significance in breast and other cancers. Given the essential role of antiviral pathways in immune ...
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026. SignificanceCompound K (CK), a significant metabolite of ginsenoside, has many unexplored anticancer chemical properties. We have developed an efficaciousCKderivative,CKD-4with significantly enhanced cancer cell penetration and cytotoxicity both in ...
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026. SignificanceAlthough eosinophils are consistently associated with inflammatory bowel disease (IBD), their precise functional roles and mechanisms of action in disease remain incompletely defined. We identify eosinophil-derived COX-2 as the main source of ...
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026. SignificanceAttention control is fundamental to human cognition, and people differ in this trait to maintain focus. These individual differences shape success in school, work, and health, but their neural basis remains unclear. Our study shows that ...
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026. SignificancePlants rely on chemical defenses to deter herbivores, yet the evolutionary processes that generate such systems remain poorly understood. Two-component defenses, in which inactive compounds are rapidly activated upon damage, offer an ideal ...
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026. SignificanceIn many sexually reproducing animals, germ cells form a syncytium as a result of incomplete cell division, sharing cytoplasmic components via intercellular bridges. However, the molecular mechanisms underlying these processes remain largely ...
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026. SignificanceUnderstanding the cognitive mechanisms underlying mental health is crucial for developing effective treatments that target causes rather than symptoms. To identify these mechanisms, researchers test large samples of online participants and ...
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026. SignificanceNOVARK, a de novo–designed kinase reporter platform featuring ultrabright signals, a large dynamic range, and minute-scale responsiveness, fulfills the full spectrum of desirable characteristics for an ideal kinase reporter. It enables ...
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026. SignificanceSocial media has transformed the speed and scope of information dissemination. While academics use these platforms to promote their own and others’ research, their causal impact on hiring remains unclear. Furthermore, persistent disparities ...
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026. SignificanceThis study sheds light on the origins and assembly of a temperate biodiversity hotspot. In examining oak evolution in Mexican and Central American mountains, we reveal that temperate forest tree dispersal into new habitats can drive rapid ...
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026.
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026.
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026.
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026.
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026.
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026.
Proceedings of the National Academy of Sciences, Volume 123, Issue 19, May 2026.