Cross-kingdom RNA interference mediated by insect salivary microRNAs may suppress plant immunity.

Communication between insects and plants relies on the exchange of bioactive molecules that traverse the species interface. Although proteinic effectors have been extensively studied, our knowledge of other molecules involved in this process remains limited. In this study, we investigate the role of salivary microRNAs (miRNAs) from the rice planthopper Nilaparvata lugens in suppressing plant immunity. A total of three miRNAs were confirmed to be secreted into host plants during insect feeding. Notably, the sequence-conserved miR-7-5P is specifically expressed in the salivary glands of N. lugens and is secreted into saliva, distinguishing it significantly from homologues found in other insects. Silencing miR-7-5P negatively affects N. lugens feeding on rice plants, but not on artificial diets. The impaired feeding performance of miR-7-5P-silenced insects can be rescued by transgenic plants overexpressing miR-7-5P. Through target prediction and experimental testing, we demonstrate that miR-7-5P targets multiple plant genes, including the immune-associated bZIP transcription factor 43 (OsbZIP43). Infestation of rice plants by miR-7-5P-silenced insects leads to the increased expression of OsbZIP43, while the presence of miR-7-5P counteracts this upregulation effect. Furthermore, overexpressing OsbZIP43 confers plant resistance against insects which can be subverted by miR-7-5P. Our findings suggest a mechanism by which herbivorous insects have evolved salivary miRNAs to suppress plant immunity, expanding our understanding of cross-kingdom RNA interference between interacting organisms.

Horizontally Transferred Salivary Protein Promotes Insect Feeding by Suppressing Ferredoxin-Mediated Plant Defenses.

Herbivorous insects such as whiteflies, planthoppers, and aphids secrete abundant orphan proteins to facilitate feeding. Yet, how these genes are recruited and evolve to mediate plant-insect interaction remains unknown. In this study, we report a horizontal gene transfer (HGT) event from fungi to an ancestor of Aleyrodidae insects approximately 42 to 190 million years ago. BtFTSP1 is a salivary protein that is secreted into host plants during Bemisia tabaci feeding. It targets a defensive ferredoxin 1 in Nicotiana tabacum (NtFD1) and disrupts the NtFD1-NtFD1 interaction in plant cytosol, leading to the degradation of NtFD1 in a ubiquitin-dependent manner. Silencing BtFTSP1 has negative effects on B. tabaci feeding while overexpressing BtFTSP1 in N. tabacum benefits insects and rescues the adverse effect caused by NtFD1 overexpression. The association between BtFTSP1 and NtFD1 is newly evolved after HGT, with the homologous FTSP in its fungal donor failing to interact and destabilize NtFD1. Our study illustrates the important roles of horizontally transferred genes in plant-insect interactions and suggests the potential origin of orphan salivary genes.

Comparative Transcriptomic Analysis Reveals Adaptation Mechanisms of Bean Bug Riptortus pedestris to Different Food Resources.

The bean bug, Riptortus pedestris (Hemiptera: Heteroptera), poses a significant threat to soybean production, resulting in substantial crop losses. Throughout the soybean cultivation period, these insects probe and suck on various parts of plants, including leaves, pods, and beans. However, the specific mechanisms by which they adapt to different food resources remain unknown. In this study, we conducted gut transcriptomic analyses of R. pedestris fed with soybean leaves, pods, and beans. A total of 798, 690, and 548 differently expressed genes (DEGs) were monitored in G-pod vs. G-leaf (comparison of insect feeding on pods and leaves), G-bean vs. G-leaf (comparison of insect feeding on beans and leaves), and G-pod vs. G-bean (comparison of insect feeding on pods and beans), respectively. When fed on pods and beans, there was a significant increase in the expression of digestive enzymes, particularly cathepsins, serine proteases, and lipases. Conversely, when soybean leaves were consumed, detoxification enzymes, such as ABC transporters and 4-coumarate-CoA ligase, exhibited higher expression. Our findings indicate that R. pedestris dynamically regulates different metabolic pathways to cope with varying food resources, which may contribute to the development of effective strategies for managing this pest.

Functional analysis of neutral lipases in bug feeding and reproduction.

BACKGROUND: The bean bug, Riptortus pedestris, is known to cause significant economic losses in soybean crops due to its seed-sucking behavior, but the mechanism of its adaptation to lipid-rich seeds remains poorly understood. To exploit potential target genes for controlling this pest, neutral lipases are functionally characterized in this study. RESULTS: In this study, a total of 69 lipases were identified in R. pedestris, including 35 neutral lipases that underwent significant expansion. The phylogeny, expression patterns, and catalytic capacity of neutral lipases were investigated and we selected six salivary gland-specific, eight gut-specific, and three ovary-specific genes for functional analysis. All three ovary-specific neutral lipases (Chr1.3195, Chr1.0994, and Chr5.0087) are critical for insect reproduction, while a few gut-specific neutral lipases (Chr4.0221 and Chr1.3207) influence insect survivorship or weight gain. In contrast, no significant phenotype change is observed when silencing salivary gland-specific neutral lipases. CONCLUSION: The lipases Chr1.3195, Chr1.0994, Chr5.0087, Chr4.0221, and Chr1.3207 are essential for R. pedestris feeding and reproduction, and the insect is highly sensitive to their deficiency, suggesting that neutral lipases are promising candidates for application in RNAi-based control of this destructive pest. © 2023 Society of Chemical Industry.

Planthopper salivary sheath protein LsSP1 contributes to manipulation of rice plant defenses.

Salivary elicitors secreted by herbivorous insects can be perceived by host plants to trigger plant immunity. However, how insects secrete other salivary components to subsequently attenuate the elicitor-induced plant immunity remains poorly understood. Here, we study the small brown planthopper, Laodelphax striatellus salivary sheath protein LsSP1. Using Y2H, BiFC and LUC assays, we show that LsSP1 is secreted into host plants and binds to salivary sheath via mucin-like protein (LsMLP). Rice plants pre-infested with dsLsSP1-treated L. striatellus are less attractive to L. striatellus nymphs than those pre-infected with dsGFP-treated controls. Transgenic rice plants with LsSP1 overexpression rescue the insect feeding defects caused by a deficiency of LsSP1 secretion, consistent with the potential role of LsSP1 in manipulating plant defenses. Our results illustrate the importance of salivary sheath proteins in mediating the interactions between plants and herbivorous insects.

The Role of Verteporfin in Prevention of Periprosthetic Capsular Fibrosis: An Experimental Study.

BACKGROUND: Capsular contracture (CC) characterized by excessive fibrosis is one of the most common complications after silicone implant surgery. Verteporfin (VP), an inhibitor of Yes-associated protein 1 (YAP1), has recently been found to reduce the fibrotic process. OBJECTIVES: The aim of this study was to use an in vivo rabbit model to evaluate the efficacy of VP for the prevention of CC. METHODS: Twenty-four New Zealand rabbits received 10-cc smooth saline silicone implants inserted in the dorsal skin and were randomly divided into 2 groups to receive 2 mL VP (1.5 mg/mL) or 2 mL phosphate-buffered saline solution instillation in the implant pocket. When the animals were killed on Day 60, capsule formation was observed both macroscopically and microscopically. Histologic evaluation included capsule thickness, fibrosis degree, and myofibroblast (α smooth muscle actin positive) content. In addition, the YAP1 expression level was examined by immunofluorescence staining. Transforming growth factor ß1, collagen I, and connective tissue growth factor expression were measured by real-time quantitative polymerase chain reaction. RESULTS: The VP-treated group exhibited thinner, more transparent capsules and less fibrosis than the control group at 60 days postsurgery (P < 0.05). Moreover, the VP treatment significantly reduced α smooth muscle actin, YAP1, transforming growth factor ß1, collagen I, and connective tissue growth factor expression levels in the capsular tissues (P < 0.05). CONCLUSIONS: VP reduced capsule formation after silicone implantation by inhibiting YAP1-mediated mechanical signaling, thereby attenuating excessive collagen deposition in the rabbit model. This preclinical study may provide a feasible strategy to prevent periprosthetic capsular fibrosis in clinical application.

Comparison of Conduits Fabricated by Fresh and Predegenerated Skeletal Muscles for Peripheral Nerve Repairing.

ABSTRACT: Reconstruction of peripheral nerve injury remains a challenge for clinical medicine. Previous reports have confirmed that external oblique muscle-fabricated nerve conduit (EMC) could effectively be used to promote peripheral nerve regeneration. In this study, we compared between conduits fabricated from fresh muscle and conduits fabricated from predegenerated muscle for the repair of peripheral nerve defects in a mouse sciatic nerve transection model. We found that the number, diameter, and myelin sheath thickness of the myelinated nerve fibers of the regenerative nerve in the EMC group were larger than those of the predegenerated-EMC (P-EMC) group eight weeks after surgery. The sciatic function index and gastrocnemius wet-weight mass ratio in the EMC group were higher than those in the P-EMC group. The Bcl-2/Bax ratio and the number of Schwann cell nucleus in the proximal nerve stumps in the EMC group were greater than those in the P-EMC group. In conclusion, our results confirmed that the use of fresh skeletal muscle nerve conduit increased the Bcl-2/Bax ratio and promoted the survival of Schwann cells of the proximal nerve stump compared with that of predegenerated skeletal muscle nerve conduits, thus achieving better functional recovery after sciatic nerve defect.

[Analysis of clinical aesthetic effect of buccal alveolar ridge preservation and connective tissue transplantation with single implant].

PURPOSE: To evaluate the clinical aesthetic effect of buccal alveolar ridge preservation (ARP) and connective tissue transplantation (CTG) in patients who received a single implant. METHODS: Forty-three patients with tooth loss admitted to the Department of Stomatology of Shunde Hospital of Southern Medical University from May 2014 to May 2016 were included in the study. Tooth extraction, ARP, implant implantation, CTG and permanent repair were performed respectively. The incidence of bleeding, depth of probing, marginal bone resorption, and red-white aesthetic effect of implants were evaluated 1 year and 3 years after surgery. The buccal mucosa thickness of implants before, immediately after CTG, 1 year and 3 years after surgery were measured. The patient satisfaction was evaluated by visual analogue scale (VAS) from masticatory function, overall aesthetics, attachment height, and color, respectively. The implant conditions at the third year after surgery were observed, and complications during follow-up were recorded. SPSS 20.0 software package was used for statistical analysis of the data. RESULTS: The follow-up rate in the first year after surgery was 100%, and that in the third year after surgery was 90.70%. One year and 3 years after operation, the aesthetic effect of the implant was satisfactory. At the 3rd year after operation, the scores of the near middle gingival papillary were significantly higher than that at the 1st year after operation (P<0.05). The buccal mucosal thickness of the implant immediately after CTG and 1 year and 3 years after surgery increased significantly compared with that before CTG (P<0.05). The buccal mucosal thickness of the implant increased 1.02 mm (relative stability: 90.12%) 1 year after operation and 1.01 mm (relative stability: 84.31%) 3 years after operation, respectively. The satisfaction scores of the patients on chewing function, overall aesthetics, attachment height and color of the implant immediately after CTG, one year after surgery and 3 years after surgery were all > 8. The 3-year survival rate of the implants was 100%, and the 3-year success rate of the implants was 97.44%. During the follow-up, two patients developed peri-implant mucositis, which was relieved after tooth cleaning, but no complications such as tissue flap necrosis, limited opening and tongue movement disorder occurred. CONCLUSIONS: ARP and CTG have good clinical and aesthetic effects on patients with tooth loss. In three years, the buccal mucosal thickness of the implant can be increased and relatively stable, which is worthy of clinical promotion and application.

Skeletal muscle-derived cells repair peripheral nerve defects in mice.

Skeletal muscle-derived cells have strong secretory function, while skeletal muscle-derived stem cells, which are included in muscle-derived cells, can differentiate into Schwann cell-like cells and other cell types. However, the effect of muscle-derived cells on peripheral nerve defects has not been reported. In this study, 5-mm-long nerve defects were created in the right sciatic nerves of mice to construct a peripheral nerve defect model. Adult female C57BL/6 mice were randomly divided into four groups. For the muscle-derived cell group, muscle-derived cells were injected into the catheter after the cut nerve ends were bridged with a polyurethane catheter. For external oblique muscle-fabricated nerve conduit and polyurethane groups, an external oblique muscle-fabricated nerve conduit or polyurethane catheter was used to bridge the cut nerve ends, respectively. For the sham group, the sciatic nerves on the right side were separated but not excised. At 8 and 12 weeks post-surgery, distributions of axons and myelin sheaths were observed, and the nerve diameter was calculated using immunofluorescence staining. The number, diameter, and thickness of myelinated nerve fibers were detected by toluidine blue staining and transmission electron microscopy. Muscle fiber area ratios were calculated by Masson's trichrome staining of gastrocnemius muscle sections. Sciatic functional index was recorded using walking footprint analysis at 4, 8, and 12 weeks after operation. The results showed that, at 8 and 12 weeks after surgery, myelin sheaths and axons of regenerating nerves were evenly distributed in the muscle-derived cell group. The number, diameter, and myelin sheath thickness of myelinated nerve fibers, as well as gastrocnemius muscle wet weight and muscle area ratio, were significantly higher in the muscle-derived cell group compared with the polyurethane group. At 4, 8, and 12 weeks post-surgery, sciatic functional index was notably increased in the muscle-derived cell group compared with the polyurethane group. These criteria of the muscle-derived cell group were not significantly different from the external oblique muscle-fabricated nerve conduit group. Collectively, these data suggest that muscle-derived cells effectively accelerated peripheral nerve regeneration. This study was approved by the Animal Ethics Committee of Plastic Surgery Hospital, Chinese Academy of Medical Sciences (approval No. 040) on September 28, 2016.

Trapped modes with extremely high quality factor in a circular array of dielectric nanorods.

In this Letter, we investigate the formation of trapped modes with near-zero group velocities in a ring chain composed of dielectric nanorods. Two kinds of bound modes are successfully identified: the regular below-continuum-resonance (BCR) modes formed at the band edge and importantly the quasi-bound-states-in-the-continuum (BIC) trapped modes (similar to the BIC in the equivalent infinite linear chain). The lowest-order trapped mode possesses the highest Q factor, which scales exponentially with the number of nanorods N as Q∼exp(0.325N) for the BCR and Q∼exp(0.662N) for the quasi-BIC. Interestingly, a moderate high Q factor ∼105 can be obtained for the quasi-BIC mode even with a very small N=8. This suggests that our nanorod-based ring resonator possesses a clear advantage over the linear chain for the same N. Our findings greatly expand the application scope of BIC-based phenomena.

l-Carnitine and heart disease.

Cardiovascular disease (CVD) is a key cause of deaths worldwide, comprising 15-17% of healthcare expenditure in developed countries. Current records estimate an annual global average of 30 million cardiac dysfunction cases, with a predicted escalation by two-three folds for the next 20-30years. Although ß-blockers and angiotensin-converting-enzymes are commonly prescribed to control CVD risk, hepatotoxicity and hematological changes are frequent adverse events associated with these drugs. Search for alternatives identified endogenous cofactor l-carnitine, which is capable of promoting mitochondrial ß-oxidation towards a balanced cardiac energy metabolism. l-Carnitine facilitates transport of long-chain fatty acids into the mitochondrial matrix, triggering cardioprotective effects through reduced oxidative stress, inflammation and necrosis of cardiac myocytes. Additionally, l-carnitine regulates calcium influx, endothelial integrity, intracellular enzyme release and membrane phospholipid content for sustained cellular homeostasis. Carnitine depletion, characterized by reduced expression of "organic cation transporter-2" gene, is a metabolic and autosomal recessive disorder that also frequently associates with CVD. Hence, exogenous carnitine administration through dietary and intravenous routes serves as a suitable protective strategy against ventricular dysfunction, ischemia-reperfusion injury, cardiac arrhythmia and toxic myocardial injury that prominently mark CVD. Additionally, carnitine reduces hypertension, hyperlipidemia, diabetic ketoacidosis, hyperglycemia, insulin-dependent diabetes mellitus, insulin resistance, obesity, etc. that enhance cardiovascular pathology. These favorable effects of l-carnitine have been evident in infants, juvenile, young, adult and aged patients of sudden and chronic heart failure as well. This review describes the mechanism of action, metabolism and pharmacokinetics of l-carnitine. It specifically emphasizes upon the beneficial role of l-carnitine in cardiomyopathy.

Levocarnitine protects H9c2 rat cardiomyocytes from H2O2-induced mitochondrial dysfunction and apoptosis.

BACKGROUND: Although the protective effects of levocarnitine in patients with ischemic heart disease are related to the attenuation of oxidative stress injury, the exact mechanisms involved have yet to be fully understood. Our aim was to investigate the potential protective effects of levocarnitine pretreatment against oxidative stress in rat H9c2 cardiomyocytes. METHODS: Cardiomyocytes were exposed to H2O2 to create an oxidative stress model. The cells were pretreated with 50, 100, or 200 µM levocarnitine for 1 hour before H2O2 exposure. RESULTS: H2O2 exposure led to significant activation of oxidative stress in the cells, characterized by reduced viability, increased intracellular reactive oxygen species, lipid peroxidation, and reduced intracellular antioxidant activity. Mitochondrial dysfunction was also observed following H2O2 exposure, reflected by the loss of mitochondrial transmembrane potential and intracellular adenosine triphosphate. These pathophysiological processes led to cardiomyocyte apoptosis through activation of the intrinsic apoptotic pathway. More importantly, the levocarnitine pretreatment attenuated the H2O2-induced oxidative injury significantly, preserved mitochondrial function, and partially prevented cardiomyocyte apoptosis during the oxidative stress reaction. Western blotting analyses suggested that levocarnitine pretreatment increased plasma protein levels of Bcl-2, reduced Bax, and attenuated cytochrome C leakage from the mitochondria in the cells. CONCLUSION: Our in vitro study indicated that levocarnitine pretreatment may protect cardiomyocytes from oxidative stress-related damage.

Use of a collagen membrane loaded with recombinant human bone morphogenetic protein-2 with collagen-binding domain for vertical guided bone regeneration.

BACKGROUND: Vertical bone regeneration of severe atrophic alveolar ridges remains a challenging procedure in implant dentistry. METHODS: The aim of this study, accordingly, is to use a rabbit vertical guided bone regeneration model to evaluate whether using a collagen membrane (CM) loaded with small doses of recombinant human bone morphogenetic protein-2 with collagen-binding domain (rhBMP-2/CBD) would enhance two-way vertical bone regeneration. In each of eight rabbits, four titanium cylinders were screwed in perforated slits made into the external cortical bones of the calvaria. The following four treatment modalities were randomly allocated: 1) cylinders filled with mineralized bone matrix and covered with CM/rhBMP-2/CBD; 2) cylinders filled with mineralized bone matrix and covered with CM/rhBMP-2; 3) cylinders filled with mineralized bone matrix and covered with CM alone; or 4) cylinders filled with mineralized bone matrix without a membrane cover. RESULTS: After 6 weeks, the new bones were examined by histologic analysis. Slender new bone trabeculae were observed in the superficial layer of the titanium cylinders covered with CM/rhBMP-2/CBD, and higher degrees of bone were observed in this group compared with the other three groups. The average area fraction of newly formed bone was significantly more in the CM/rhBMP-2/CBD group compared with the CM/rhBMP-2, CM, or the no membrane control groups (all P <0.01). CONCLUSIONS: The present study demonstrates that CMs loaded with small doses of rhBMP-2/CBD induce new bone formation not only from the surface of the native bone, but also from the superficial structures. The augmented new bone, therefore, is improved in both quantity and quality.

[Effect of different wave-length ultraviolet light-treated micro-arc oxidation titanium surfaces on the physicochemical properties and bioactivity in vitro].

OBJECTIVE: To study the effects of ultraviolet (UV) light-treatment on the physicochemical properties and bioactivity of micro-arc oxidation (MAO) titanium surfaces in vitro. METHODS: The pure titanium were prepared using MAO. MAO titanium samples were treated with 15 W bactericidal lamp UVC [λ = (250 ± 20) nm] or 15 W mercury lamp [λ = (360 ± 20) nm] for 24 h under ambient conditions. Three sample groups were prepared: MAO, UVA treated after MAO (MAO + UVA), UVC treated after MAO (MAO + UVC). The surface physicochemical properties were evaluated using scanning electron microscopy (SEM), contact angle measuring device, energy dispersive X-ray spectrometer (EDX), and X-ray diffraction (XRD). Bicinchoninic acid (BCA) based colorimetric detection was used to quantify the percentage of albumin adsorption after 2 h, 6 h, and 24 h incubation on the titanium surfaces. The rates of MG-63 cells attached to each group titanium surfaces were calculated by nucleus immunofluorescence using Hoechst 33342 after 1 h, 2 h, and 4 h incubation. SEM was used to observe cell morphology on titanium surfaces in each group. RESULTS: No obvious differences in surface topography, TiO(2) crystal and elemental composition were detected on titanium surfaces with or without UV treatment. Statistically significant difference in contact angles among MAO + UVC group (65.34 ± 1.16)°, MAO + UVA group (44.64 ± 1.28)°, and MAO group (3.41 ± 0.48)° were found (P < 0.001). The percentage of albumin adsorption reached the plateau after 2 h incubation on MAO + UVC titanium surfaces (48.16 ± 1.24)%, which was higher than those in MAO [(8.22 ± 2.99)%] and MAO + UVA groups [(5.29 ± 2.27)%, P < 0.001]. The rates of cells attached to the surfaces of MAO + UVC titanium was greater than that on MAO surfaces and MAO + UVA surfaces after 1 h [(40.71 ± 4.08)%], 2 h [(53.72 ± 2.38)%], 4 h [(70.32 ± 2.85)%] incubation (P < 0.05). The MAO + UVC surfaces remarkably enhanced the spread of MG-63 cells, however, there was no significant difference between the group of MAO and MAO + UVA. CONCLUSIONS: Pretreatment of micro-arc oxidation titanium with UVC light considerably improved the surface bioactivity to MG-63 cells, which showed an increase in cellular attachment and spread.