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PIWI-clade proteins harness piRNAs of 24–33 nt in length. Of great puzzles are how PIWI-clade proteins incorporate piRNAs of different sizes and whether the size matters to PIWI/piRNA function. Here we report that a PIWI-Ins module unique in PIWI-clade proteins helps define the length of piRNAs. Deletion of PIWI-Ins in Miwishifts MIWI to load with shorter piRNAs and causes spermiogenic failure in mice, demonstrating the functional importance of this regulatory module. Mechanistically, we show that longer piRNAs provide additional complementarity to target mRNAs, thereby enhancing the assembly of the MIWI/eIF3f/HuR super-complex for translational activation. Importantly, we identify a c.1108C>T (p.R370W) mutation of HIWI(human PIWIL1) in infertile men and demonstrate in Miwiknock-in mice that this genetic mutation impairs male fertility by altering the property of PIWI-Ins in selecting longer piRNAs. These findings reveal a critical role of PIWI-Ins-ensured longer piRNAs in fine-tuning MIWI/piRNA targeting capacity, proven essential for spermatid development and male fertility.

Efforts are made to enhance the inherent potential of extracellular vesicles (EVs) by utilizing 3D culture platforms and engineered strategies for functional cargo‐loading. Three distinct types of adipose mesenchymal stem cells‐derived EVs (ADSCs‐EVs) are successfully isolated utilizing 3D culture platforms consisting of porous gelatin methacryloyl (PG), PG combined with sericin methacryloyl (PG/SerMA), or PG combined with chondroitin sulfate methacryloyl (PG/ChSMA). These correspond to PG‐EVs, PG/SerMA‐EVs, and PG/ChSMA‐EVs, respectively. Unique microRNA (miRNA) profiles are observed in each type of ADSCs‐EVs. Notably, PG‐EVs encapsulate higher levels of hsa‐miR‐455‐3p and deliver more hsa‐miR‐455‐3p to chondrocytes, which results in the activation of the hsa‐miR‐455‐3p/PAK2/Smad2/3 axis and the subsequent hyaline cartilage regeneration. Furthermore, the functionality of PG‐EVs is optimized through engineered strategies, including agomir/lentivirus transfection, electroporation, and Exo‐Fect transfection. These strategies, referred to as Agomir‐EVs, Lentivirus‐EVs, Electroporation‐EVs, and Exo‐Fect‐EVs, respectively, are ranked based on their efficacy in encapsulating hsa‐miR‐455‐3p, delivering hsa‐miR‐455‐3p to chondrocytes, and promoting cartilage formation via the hsa‐miR‐455‐3p/PAK2/Smad2/3 axis. Notably, Exo‐Fect‐EVs exhibit the highest efficiency. Collectively, the 3D culture conditions and engineered strategies have an impact on the miRNA profiles and cartilage regeneration capabilities of ADSCs‐EVs. The findings provide valuable insights into the mechanisms underlying the promotion of cartilage regeneration by ADSCs‐EVs. This study reports that culture conditions and engineered strategies affect the miRNA profiles and cartilage regeneration potential of adipose mesenchymal stem cells‐derived extracellular vesicles (EVs). Different types of engineered EVs are ranked based on their efficacy in encapsulating and delivering hsa‐miR‐455‐3p, with Exo‐Fect‐EVs being the most effective. As expected, Exo‐Fect‐EVs yield promising results in cartilage formation by activating hsa‐miR‐455‐3p/PAK2/Smad2/3 axis.

Herbivore-induced plant volatiles (HIPVs) play a key role in the interactions between plants and herbivorous insects, as HIPVs can promote or deter herbivorous insects’ behavior. While aphids are common and serious phloem-feeding pests in farmland ecosystems, little is known about how aphids use their sensitive olfactory system to detect HIPVs. In this study, the antennal transcriptomes of the aphid species Megoura crassicaudawere sequenced, and expression level analyses of M. crassicaudaodorant receptors (ORs) were carried out. To investigate the chemoreception mechanisms that M. crassicaudauses to detect HIPVs, we performed in vitrofunctional studies of the ORs using 11 HIPVs reported to be released by aphid-infested plants. In total, 54 candidate chemosensory genes were identified, among which 20 genes were ORs. McraOR20and McraOR43were selected for further functional characterization because their homologs in aphids were quite conserved and their expression levels in antennae of M. crassicaudawere relatively high. The results showed that McraOR20 specifically detected cis-jasmone, as did its ortholog ApisOR20 from the pea aphid Acyrthosiphon pisum, while McraOR43 did not respond to any of the HIPV chemicals that were tested. This study characterized the ability of the homologous OR20 receptors in the two aphid species to detect HIPV cis-jasmone, and provides a candidate olfactory target for mediating aphid behaviors.

Pea aphid, Acyrthosiphon pisum, is a serious pest of many different leguminous plants, and it mainly relies on its odorant receptors (Ors) to discriminate among host species. However, less is known about the role that Ors play in the host plant location. In this study, we identified a novel conserved odorant receptor clade by phylogenetic analysis, and conducted the functional analysis of ApisOr23 in A. pisum. The results showed that the homologous Ors from A. pisum, Aphis glycinesand Aphis gossypiishare 94.28% identity in amino acid sequences. Moreover, conserved motifs were analyzed using the annotated homologous Or23 from eight aphid species, providing further proof of the high conservation level of the Or23 clade. According to the tissue expression pattern analysis, ApisOr23was mainly expressed in the antennae. Further functional study using a heterologous Xenopusexpression system revealed that ApisOr23 was tuned to five plant volatiles, namely trans-2-hexen-1-al, cis-2-hexen-1-ol, 1-heptanol, 4´-ethylacetophenone, and hexyl acetate. Among them, trans-2-hexen-1-al, which is one of the main volatile organic compounds released from legume plants, activated the highest response of ApisOr23. Our findings suggest that the conserved Or23 clade in most aphid species might play an important role in host plant detection.