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The forkhead box O (FoxO) protein is the main transcriptional effector downstream of the insulin/insulin‐like signaling pathway and regulates many developmental and physiological processes. Holometabolous insects with loss‐of‐function mutations in FoxO exhibit phenotypes distinct from those of hemimetabolous insects in which RNA interference was used. Despite the functional importance of FoxO, whether hemimetabolous insects share an evolutionally conserved function of FoxO with holometabolous insects remains to be clarified. We used the clustered regularly interspaced short palindromic repeats/CRISPR‐associated 9 (CRISPR/Cas9) genome editing‐system to establish a homozygous FoxO‐null mutant (NlFoxO4E) of the wing‐dimorphic brown planthopper (BPH) Nilaparvata lugens, an economically important insect pest of rice fields. The phenotypes of NlFoxO4E mutants included extended nymphal duration, shortened lifespan, reduced reproduction, and decreased stress resistance. In addition, depletion of NlFoxO promoted cell proliferation in wing buds and led to 100% long‐winged morphs, in stark contrast to short‐winged wild‐type BPHs. These findings indicate that NlFoxO is highly functionally conserved with its counterpart in holometabolous insects, and is required for optimal fitness of N. lugens. The insights from FoxO studies may facilitate the identification of potential target genes for BPH control applications. [ABSTRACT FROM AUTHOR]

Aberrantly up-regulated activity of the type II transmembrane protease Matriptase-1 has been associated with the development and progression of a range of epithelial-derived carcinomas, and a variety of signaling pathways can mediate Matriptase-dependent tumorigenic events. During mammalian carcinogenesis, gain of Matriptase activity often results from imbalanced ratios between Matriptase and its cognate transmembrane inhibitor Hai1. Similarly, in zebrafish, unrestrained Matriptase activity due to loss of hai1a results in epidermal pre-neoplasms already during embryogenesis. Here, based on our former findings of a similar tumor-suppressive role for the Na+/K+-pump beta subunit ATP1b1a, we identify epithelial polarity defects and systemic hypotonic stress as another mode of aberrant Matriptase activation in the embryonic zebrafish epidermis in vivo. In this case, however, a different oncogenic pathway is activated which contains PI3K, AKT and NFkB, rather than EGFR and PLD (as in hai1a mutants). Strikingly, epidermal pre-neoplasm is only induced when epithelial polarity defects in keratinocytes (leading to disturbed Matriptase subcellular localization) occur in combination with systemic hypotonic stress (leading to increased proteolytic activity of Matriptase). A similar combinatorial effect of hypotonicity and loss of epithelial polarity was also obtained for the activity levels of Matriptase-1 in human MCF-10A epithelial breast cells. Together, this is in line with the multi-factor concept of carcinogenesis, with the notion that such factors can even branch off from one and the same initiator (here ATP1a1b) and can converge again at the level of one and the same mediator (here Matriptase). In sum, our data point to tonicity and epithelial cell polarity as evolutionarily conserved regulators of Matriptase activity that upon de-regulation can constitute an alternative mode of Matriptase-dependent carcinogenesis in vivo. Author summary: Deciphering the mechanisms of carcinogenesis is pivotal not only for the treatment of the disease, but also for identifying potential risk factors. Model systems can help to achieve this goal. Work with zebrafish has identified several evolutionarily conserved factors driving pre-neoplastic events in the epidermis already at embryonic stages. This study focuses on the oncogene ST14, encoding the type II transmembrane protease Matriptase-1 that upon hyperactivation—as for instance due to genetic loss of its cognate transmembrane inhibitor Hai1—can drive different carcinomas. Here, we identify two additional conditions promoting oncogenic Matriptase-1 hyperactivation: hypotonic stress and compromised epithelial cell polarity. Of note, these two conditions need to occur together for Matriptase-dependent induction of pre-neoplasms in the embryonic zebrafish epidermis, in line with the multi-factor concept of carcinogenesis. Hypotonicity increases the proteolytic activity of Matriptase, while epithelial polarity defects lead to a subcellular mis-localization of Matriptase in outer epidermal cells, bringing more of it into close contact to underlying basal cells and thus inducing oncogenic pathways in them. Together, our work identifies novel modes of oncogenic Matriptase hyperactivation and function in vivo, originating from cells of the tumor environment, rather than from the tumor cells themselves. [ABSTRACT FROM AUTHOR]

BACKGROUND: The migratory brown planthopper (BPH), Nilaparvata lugens (Hemiptera: Delphacidae), is the most destructive pest affecting rice plants in Asia and feeds exclusively on rice. Studies have investigated the olfactory response of BPHs to the major rice volatile compounds in rice. The insect olfactory co‐receptor (Orco) is a crucial component of the olfactory system and is essential for odorant detection. Functional analysis of the Orco gene in BPHs would aid in the identification of their host preference. RESULTS: We identified the BPH Orco homologue (NlOrco) by Blast searching the BPH transcriptome with the Drosophila Orco gene sequence. Spatiotemporal analysis indicated that NlOrco is first expressed in the later egg stage, and is expressed mainly in the antennae in adult females. A NlOrco‐knockout line (NlOrco−/−) was generated through clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9‐mediated mutagenesis. The NlOrco−/− mutants showed no response to rice volatile compounds and consequently no host‐plant preference. In addition, NlOrco−/− mutants exhibited extended nymphal duration and impaired fecundity compared with wild‐type BPHs. CONCLUSION: Our findings indicated that BPHs exhibit strong olfactory responses to major rice volatile compounds and suggest that NlOrco is required for the maximal fitness of BPHs. Our results may facilitate the identification of potential target genes or chemical compounds for BPH control applications. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The homeotic complex gene Abdominal‐B (Abd‐B) is involved in regulating the development of posterior abdomens and has been extensively studied in holometabolous insects. However, the function of Abd‐B in hemimetabolous insects is not fully understood. Here, we functionally characterize an Abd‐B homologue in the brown planthopper (BPH), Nilaparvata lugens. The full‐length cDNA of the N. lugens Abd‐B homologue (NlAbd‐B) is 2334 nt, with an open reading frame of 1113 bp. NlAbd‐B has the highest expression level at the egg stage relative to the nymphal and adult stages and is mainly expressed in the fourth to the ninth abdominal segment of embryos. RNA interference (RNAi)‐mediated knockdown of NlAbd‐B in nymphs disrupted the development of genitalia both in females and males and caused a genitalia‐to‐leg transformation. Parental RNAi of NlAbd‐B in both female and male adults caused an extra abdominal segment in offspring nymphs, while parental RNAi of the N. lugens abdominal‐A homologue in both female and males adults led to embryos with leg‐like appendages on the second to the eighth abdominal segment. These findings suggest that NlAbd‐B plays a pivotal role in genital development and posterior abdominal patterning and thus highlight the conservational role of Abd‐B in holometabolous and hemimetabolous insects. [ABSTRACT FROM AUTHOR]

The extracellular matrix architecture is composed of supramolecular fibrillar networks that define tissue specific cellular microenvironments. Hemicentins (Hmcn1 and Hmcn2) are ancient and very large members (> 600 kDa) of the fibulin family, whose short members are known to guide proper morphology and functional behavior of specialized cell types predominantly in elastic tissues. However, the tissue distribution and function of Hemicentins within the cellular microenvironment of connective tissues has remained largely unknown. Performing in situ hybridization and immunofluorescence analyses, we found that mouse Hmcn1 and Hmcn2 show a complementary distribution throughout different tissues and developmental stages. In postnatal dermal–epidermal junctions (DEJ) and myotendinous junctions (MTJ), Hmcn1 is primarily produced by mesenchymal cells (fibroblasts, tenocytes), Hmcn2 by cells of epithelial origin (keratinocytes, myocytes). Hmcn1−/− mice are viable and show no overt phenotypes in tissue tensile strength and locomotion tests. However, transmission electron microscopy revealed ultrastructural basement membrane (BM) alterations at the DEJ and MTJ of Hmcn1−/− mice, pointing to a thus far unknown role of Hmcn1 for BM and connective tissue boundary integrity. [ABSTRACT FROM AUTHOR]

A single insulin receptor (InR) gene has been identified and extensively studied in model species ranging from nematodes to mice. However, most insects possess additional copies of InR, yet the functional significance, if any, of alternate InRs is unknown. Here, we used the wing-dimorphic brown planthopper (BPH) as a model system to query the role of a second InR copy in insects. NlInR2 resembled the BPH InR homologue (NlInR1) in terms of nymph development and reproduction, but revealed distinct regulatory roles in fuel metabolism, lifespan, and starvation tolerance. Unlike a lethal phenotype derived from NlInR1 null, homozygous NlInR2 null mutants were viable and accelerated DNA replication and cell proliferation in wing cells, thus redirecting short-winged–destined BPHs to develop into long-winged morphs. Additionally, the proper expression of NlInR2 was needed to maintain symmetric vein patterning in wings. Our findings provide the first direct evidence for the regulatory complexity of the two InR paralogues in insects, implying the functionally independent evolution of multiple InRs in invertebrates. Author summary: The highly conserved insulin/insulin-like growth factor signaling pathway plays a pivotal role in growth, development, and various physiological processes across a wide phylogeny of organisms. Unlike a single InR in the model species such as the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans, most insect lineages have two or even three InR copies. However, the function of the alternative InRs remains elusive. Here, we created a homozygous mutation for a second insulin receptor (InR2) in the wing-dimorphic brown planthopper (BPH), Nilaparvata lugens, using the clustered regularly interspaced palindromic repeats/CRISPR-associated (CRISPR/Cas9) system. Our findings revealed that InR2 possesses functions distinct from the BPH InR homologue (NlInR1), indicating that multiple InR paralogues may have evolved independently and may have functionally diversified in ways more complex than previously expected in invertebrates. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the value of a horizontal rafting plate in treating tibial plateau fractures. Methods: The data of 24 patients in whom a horizontal rafting plate was used to treat a tibial plateau fracture between October 2014 and January 2018 were retrospectively analyzed, including 16 males and 8 females, aged 21–63 years old, with an average of 40 ± 14.68 years. The fractures included 13 in the left knee and 11 in the right knee. The places where the horizontal rafting plate were used included the anterior margin of tibia, anterolateral tibia, and posterolateral tibia. All cases were followed up for 12–24 months, with an average follow‐up of 17.5 ± 5.0 months. At the last follow‐up, the Rasmussen radiological criteria were used to evaluate the effect of fracture reduction and fixation. The knee joint function was evaluated using the Rasmussen functional score. Computed tomography (CT) scanning and three‐dimensional reconstruction were performed preoperatively and postoperatively, with the quality of reduction of the fractured articular surface clarified by the final follow‐up. The flexion and extension abilities of the knee joint were also measured in the postoperative follow‐up. Results: Preoperative CT scanning showed that the gap of the tibial plateau was 8.00 ± 1.40 (5–24) mm. The heights of the fracture of the articular surface at all three sites during the final follow‐ups were significantly different from the height before the surgery (P < 0.05). The vertical distance between the articular line and the highest point of the articular surface after reduction was 0.17 ± 0.05 mm. Anatomic reductions were obtained in 24 patients. The Rasmussen functional score after surgeries was 27.25 ± 0.94 points. Bony union was achieved in all the patients. According to the Rasmussen radiological criteria, the scores during the last follow‐up were as follows: the total score was 13–18 points, with an average of 16.00 ± 1.72 points; the scores were excellent in 17 cases and good in seven cases. Therefore, 100% of results were excellent or good. No infection or fracture nonunion was found. Conclusion: Using a horizontal plate can be an effective method for treating special types of fractures of the tibial plateau, including the anterior margin and anterolateral and posterolateral tibial plateau, with satisfactory treatment efficacy. [ABSTRACT FROM AUTHOR]

Objective: The aim of the present study was to summarize the clinical characteristics, treatment strategies, and clinical results for anterior tibial plateau fractures caused by hyperextension injuries. Methods: We performed a retrospective analysis of 26 cases of anterior tibial plateau fractures that were treated with open reduction and internal fixation from January 2016 to December 2019, including 16 men and 10 women, aged 26–68 years old, with an average age of 47 ± 12.5 years. According to the three‐column theory classification, there were 16 cases of single‐column fractures (9 cases of anteromedial fractures and 7 cases of anterolateral fractures), 3 cases of two‐column fractures (anteromedial + anterolateral fractures), and 7 cases of three‐column fractures. Options for the surgical approach included anteromedial, anterolateral, modified anterior median, and anterolateral + posteromedial incision. The implants included a T‐shaped plate, an L‐shaped plate, a horizontal plate, and a TomoFix plate. The surgical approach and fixation method were selected based on the characteristics of the anterior tibial fracture. The Rasmussen radiological criteria were used to evaluate the effects of fracture reduction and fixation. The knee joint function was evaluated using the knee function evaluation criteria of the Hospital for Special Surgery. Medial and lateral stress tests, the Lachman test, and the pivot shift test were used to evaluate the stability of the knee joint. The range of knee motion was recorded. Results: All cases were followed up for 12–24 months, with an average follow up of 15.7 months. The operation time was (148 ± 42) min; the intraoperative blood loss was (150 ± 50) mL. A total of 22 cases were anatomically reduced and 4 cases were well‐reduced, and the compression reduction rate was 100%. According to the Rasmussen radiology scoring, 17 cases were excellent and 9 cases were good. The excellent and good rate was 100%. The fracture healing time was 3.3 months. There is no difference in fracture healing time for different fracture types. Both the Lachman and pivot shift test findings were normal in 24 patients and nearly normal in 2 patients. The posterior drawer test was normal in 25 patients and close to normal in 1 patient. The varus stress test was normal in 24 patients and nearly normal in 2 patients, while the valgus stress test was normal in 23 patients, nearly normal in 2 patients, and abnormal in 1 patient. The range of motion (ROM) was 100°–137°, with an average of 125° ± 11.7°. The Hospital for Special Surgery (HSS) knee score at the last follow up was 79–98 points, with an average of 87.54 ± 8.36 points; the results were excellent in 21 cases and good in 5 cases. Therefore, 100% of results were excellent or good. Two cases had superficial wound infections after the operation. The recovery of 2 patients with common peroneal nerve injury was poor. Conclusion: The appropriate surgical approach and fixation method were performed according to the different positions of the anterior tibial fracture and satisfactory results were obtained after surgery. [ABSTRACT FROM AUTHOR]

Wing polymorphism is an evolutionary feature found in a wide variety of insects, which offers a model system for studying the evolutionary significance of dispersal. In the wing-dimorphic planthopper Nilaparvata lugens, the insulin/insulin-like growth factor signaling (IIS) pathway acts as a 'master signal' that directs the development of either long-winged (LW) or short-winged (SW) morphs via regulation of the activity of Forkhead transcription factor subgroup O (NlFoxO). However, downstream effectors of the IIS–FoxO signaling cascade that mediate alternative wing morphs are unclear. Here we found that vestigial (Nlvg), a key wing-patterning gene, is selectively and temporally regulated by the IIS–FoxO signaling cascade during the wing-morph decision stage (fifth-instar stage). RNA interference (RNAi)-mediated silencing of Nlfoxo increase Nlvg expression in the fifth-instar stage (the last nymphal stage), thereby inducing LW development. Conversely, silencing of Nlvg can antagonize the effects of IIS activity on LW development, redirecting wing commitment from LW to the morph with intermediate wing size. In vitro and in vivo binding assays indicated that NlFoxO protein may suppress Nlvg expression by directly binding to the first intron region of the Nlvg locus. Our findings provide a first glimpse of the link connecting the IIS pathway to the wing-patterning network on the developmental plasticity of wings in insects, and help us understanding how phenotypic diversity is generated by the modification of a common set of pattern elements. Author summary: Many insects are capable of developing into either long-winged or short-winged adults, but the underlying molecular basis remains largely unknown. Pioneer studies showed that the insulin/insulin-like growth factor signaling pathway acts as a 'master signal' that directs wing buds to develop into long or short wings in the wing-dimorphic planthopper, Nilaparvata lugens. However, downstream effectors mediating the IIS pathway effects are unknown. Our findings highlight that vestigial, a key wing-patterning gene, is a main downstream effector that mediates the IIS activity on the development of alternative wing morphs during the wing-morph decision stage. The molecular mechanism of wing formation, including the function of vestigial, has been studied in great depth in the model insect Drosophila melanogaster. Our data provide a first glimpse of the link connecting the IIS pathway to the wing-patterning network in regulating developmental plasticity of wings in insects. [ABSTRACT FROM AUTHOR]

Nuclear factor Y (NF-Y) is a heterotrimeric transcription factor with the ability to bind to a CCAAT box in nearly all eukaryotes. However, the function of NF-Y in the life-history traits of insects is unclear. Here, we identified three NF-Y subunits, Nl NF-YA, Nl NF-YB, and Nl NF-YC, in the wing-dimorphic brown planthopper (BPH), Nilaparvata lugens. Spatio-temporal analysis indicated that NlNF-YA , NlNF-YB , and NlNF-YC distributed extensively in various body parts of fourth-instar nymphs, and were highly expressed at the egg stage. RNA interference (RNAi)-mediated silencing showed that knockdown of NlNF-YA , NlNF-YB , or NlNF-YC in third-instar nymphs significantly extended the fifth-instar duration, and decreased nymph-adult molting rate. The addition of 20-hydroxyecdysone could specifically rescue the defect in adult molting caused by NlNF-YA RNAi, indicating that Nl NF-Y might modulate the ecdysone signaling pathway in the BPH. In addition, NlNF-YA RNAi, NlNF-YB RNAi, or NlNF-YC RNAi led to small and moderately malformed forewings and hindwings, and impaired the normal assembly of indirect flight muscles. Adult BPHs treated with NlNF-YA RNAi, NlNF-YB RNAi, or NlNF-YC RNAi produced fewer eggs, and eggs laid by these BPHs had arrested embryogenesis. These findings deepen our understanding of NF-Y function in hemipteran insects. [ABSTRACT FROM AUTHOR]