Mechanical force modulates macrophage proliferation via Piezo1-AKT-Cyclin D1 axis.

Orthodontic tooth movement (OTM) is induced by biomechanical stimuli and facilitated by periodontal tissue remodeling, where multiple immune cells participate in this progression. It has been demonstrated that macrophage is essential for mechanical force-induced tissue remodeling. In this study, we first found that mechanical force significantly induced macrophage proliferation in human periodontal samples and murine OTM models. Yet, how macrophages perceive mechanical stimuli and thereby modulate their biological behaviors remain elusive. To illustrate the mechanisms of mechanical force-induced macrophage proliferation, we subsequently identified Piezo1, a novel mechanosensory ion channel, to modulate macrophage response subjected to mechanical stimuli. Mechanical force upregulates Piezo1 expression in periodontal tissues and cultured bone-marrow-derived macrophages (BMDMs). Remarkably, suppressing Piezo1 with GsMTx4 retarded OTM through reduced macrophage proliferation. Moreover, knockdown of Piezo1 effectively inhibited mechanical force-induced BMDMs proliferation. RNA sequencing was further performed to dissect the underlying mechanisms of Piezo1-mediated mechanotransduction utilizing mechanical stretch system. We revealed that Piezo1-activated AKT/GSK3ß signaling was closely associated with macrophage proliferation upon mechanical stimuli. Importantly, Cyclin D1 (Ccnd1) was authenticated as a critical downstream factor of Piezo1 that facilitated proliferation by enhancing Rb phosphorylation. We generated genetically modified mice in which Ccnd1 could be deleted in macrophages in an inducible manner. Conditional ablation of Ccnd1 inhibited periodontal macrophage proliferation and therefore delayed OTM. Overall, our findings highlight that proliferation driven by mechanical force is a key process by which macrophages infiltrate in periodontal tissue during OTM, where Piezo1-AKT-Ccnd1 axis plays a pivotal role.

Mechanical force induces macrophage-derived exosomal UCHL3 promoting bone marrow mesenchymal stem cell osteogenesis by targeting SMAD1.

BACKGROUND: Orthodontic tooth movement (OTM), a process of alveolar bone remodelling, is induced by mechanical force and regulated by local inflammation. Bone marrow-derived mesenchymal stem cells (BMSCs) play a fundamental role in osteogenesis during OTM. Macrophages are mechanosensitive cells that can regulate local inflammatory microenvironment and promote BMSCs osteogenesis by secreting diverse mediators. However, whether and how mechanical force regulates osteogenesis during OTM via macrophage-derived exosomes remains elusive. RESULTS: Mechanical stimulation (MS) promoted bone marrow-derived macrophage (BMDM)-mediated BMSCs osteogenesis. Importantly, when exosomes from mechanically stimulated BMDMs (MS-BMDM-EXOs) were blocked, the pro-osteogenic effect was suppressed. Additionally, compared with exosomes derived from BMDMs (BMDM-EXOs), MS-BMDM-EXOs exhibited a stronger ability to enhance BMSCs osteogenesis. At in vivo, mechanical force-induced alveolar bone formation was impaired during OTM when exosomes were blocked, and MS-BMDM-EXOs were more effective in promoting alveolar bone formation than BMDM-EXOs. Further proteomic analysis revealed that ubiquitin carboxyl-terminal hydrolase isozyme L3 (UCHL3) was enriched in MS-BMDM-EXOs compared with BMDM-EXOs. We went on to show that BMSCs osteogenesis and mechanical force-induced bone formation were impaired when UCHL3 was inhibited. Furthermore, mothers against decapentaplegic homologue 1 (SMAD1) was identified as the target protein of UCHL3. At the mechanistic level, we showed that SMAD1 interacted with UCHL3 in BMSCs and was downregulated when UCHL3 was suppressed. Consistently, overexpression of SMAD1 rescued the adverse effect of inhibiting UCHL3 on BMSCs osteogenesis. CONCLUSIONS: This study suggests that mechanical force-induced macrophage-derived exosomal UCHL3 promotes BMSCs osteogenesis by targeting SMAD1, thereby promoting alveolar bone formation during OTM.

Rational Design of Bisphosphonate Lipid-like Materials for mRNA Delivery to the Bone Microenvironment.

The development of lipid nanoparticle (LNP) formulations for targeting the bone microenvironment holds significant potential for nucleic acid therapeutic applications including bone regeneration, cancer, and hematopoietic stem cell therapies. However, therapeutic delivery to bone remains a significant challenge due to several biological barriers, such as low blood flow in bone, blood-bone marrow barriers, and low affinity between drugs and bone minerals, which leads to unfavorable therapeutic dosages in the bone microenvironment. Here, we construct a series of bisphosphonate (BP) lipid-like materials possessing a high affinity for bone minerals, as a means to overcome biological barriers to deliver mRNA therapeutics efficiently to the bone microenvironment in vivo. Following in vitro screening of BP lipid-like materials formulated into LNPs, we identified a lead BP-LNP formulation, 490BP-C14, with enhanced mRNA expression and localization in the bone microenvironment of mice in vivo compared to 490-C14 LNPs in the absence of BPs. Moreover, BP-LNPs enhanced mRNA delivery and secretion of therapeutic bone morphogenetic protein-2 from the bone microenvironment upon intravenous administration. These results demonstrate the potential of BP-LNPs for delivery to the bone microenvironment, which could potentially be utilized for a range of mRNA therapeutic applications including regenerative medicine, protein replacement, and gene editing therapies.

Fucoidan inhibits tooth movement by promoting restorative macrophage polarization through the STAT3 pathway.

Retention after treatment and effective anchorage control are two essential factors in orthodontics. Our study aimed to explore the effects of fucoidan on orthodontic tooth movement (OTM) and the involvement of macrophages. We established a murine OTM model to test the effect of fucoidan administration. We found that mice injected with fucoidan had a deceleration in OTM and a higher bone mineral density. Moreover, fucoidan increased the proportion of F4/80+ CD206+ macrophages and promoted the messenger RNA expression of Arg-1, CD206, and IL-10 at both in vivo and in vitro levels. In addition, macrophages showed lower expression of TNF-α, IL-1ß, and IL-6 and a decrease in F4/80+ CD11c+ cells. Mechanistically, the level of phosphorylated STAT3 was elevated in unpolarized and restorative macrophages after treatment with fucoidan. Taken together, our findings suggest that fucoidan treatment inhibits OTM and enhances the stability of teeth after movement by promoting restorative macrophages through the STAT3 pathway.

Targeted delivery of hybrid nanovesicles for enhanced brain penetration to achieve synergistic therapy of glioma.

Blood-brain barrier (BBB) obstructing brain drug delivery severely hampers the therapeutic efficacy towards glioma. An efficient brain delivery strategy is of paramount importance for the treatment of glioma. Inspired by brain targeting exosome, biomimetic BBB penetrated hybrid (pHybrid) nanovesicles, engineered by membrane fusion between blood exosome and tLyp-1 peptide modified liposome, is explored for brain targeting drug delivery. Transferrin receptor (TfR) on pHybrid nanovesicles facilitates the BBB transcytosis into brain parenchyma, and eventually endocytosed by glioma cells and diffusion to extra-vascular tumor tissues under the guidance of tLyp-1 peptide. pHybrid nanovesicles co-loaded with salvianolic acid B (SAB) and cryptotanshinone (CPT), which is constructed by membrane hybridization of blood exosome loaded with SAB and tLyp-1 modified liposome loaded with CPT, are explored for cytotoxic and anti-angiogenetic therapy towards glioma. Upon accumulation at tumor site, the loaded CPT and SAB shows synergistic effects towards glioma from cytotoxicity on cancer cells and anti-angiogenesis on tumor, respectively. Overall, this study provides a biomimetic nanoplatform for increased BBB transcytosis into brain parenchyma, which serves as a prospective strategy for delivering therapeutic agents against glioma through synergistic mechanisms.

CCR2+ Macrophages Promote Orthodontic Tooth Movement and Alveolar Bone Remodeling.

During mechanical force-induced alveolar bone remodeling, macrophage-mediated local inflammation plays a critical role. Yet, the detailed heterogeneity of macrophages is still unknown. Single-cell RNA sequencing was used to study the transcriptome heterogeneity of macrophages during alveolar bone remodeling. We identified macrophage subclusters with specific gene expression profiles and functions. CellChat and trajectory analysis revealed a central role of the Ccr2 cluster during development, with the CCL signaling pathway playing a crucial role. We further demonstrated that the Ccr2 cluster modulated bone remodeling associated inflammation through an NF-κB dependent pathway. Blocking CCR2 could significantly reduce the Orthodontic tooth movement (OTM) progression. In addition, we confirmed the variation of CCR2+ macrophages in human periodontal tissues. Our findings reveal that mechanical force-induced functional shift of the Ccr2 macrophages cluster mediated by NF-κB pathway, leading to a pro-inflammatory response and bone remodeling. This macrophage cluster may represent a potential target for the manipulation of OTM.

Rational design of anti-inflammatory lipid nanoparticles for mRNA delivery.

Lipid nanoparticles (LNPs) play a crucial role in delivering messenger RNA (mRNA) therapeutics for clinical applications, including COVID-19 mRNA vaccines. While mRNA can be chemically modified to become immune-silent and increase protein expression, LNPs can still trigger innate immune responses and cause inflammation-related adverse effects. Inflammation can in turn suppress mRNA translation and reduce the therapeutic effect. Dexamethasone (Dex) is a widely used anti-inflammatory corticosteroid medication that is structurally similar to cholesterol, a key component of LNPs. Here, we developed LNP formulations with anti-inflammatory properties by partially substituting cholesterol with Dex as a means to reduce inflammation. We demonstrated that Dex-incorporated LNPs effectively abrogated the induction of tumor necrosis factor alpha (TNF-ɑ) in vitro and significantly reduced its expression in vivo. Reduction of inflammation using this strategy improved in vivo mRNA expression in mice by 1.5-fold. Thus, we envision that our Dex-incorporated LNPs could potentially be used to broadly to reduce the inflammatory responses of LNPs and enhance protein expression of a range of mRNA therapeutics.

Effect of pretreatment with Phanerochaete chrysosporium on physicochemical properties and pyrolysis behaviors of corn stover.

Fungal pretreatment can selectively degrade partial biomass components, which undoubtedly exerts a significant influence on biomass pyrolysis behavior. The corn stover was pretreated with Phanerochaete chrysosporium, and its influence on the physicochemical properties and pyrolysis behaviors of biomass together with the product characteristics were investigated. The Phanerochaete chrysosporium was more active to degrade hemicellulose and lignin. The hemicellulose and lignin contents in corn stover were decreased by 35.14 % and 31.80 %, respectively, after five weeks pretreatment, compared to the untreated sample. The reaction activation energy decreased from 52.89 kJ·mol-1 for the untreated sample to 40.88 kJ·mol-1 for the sample pretreated for five weeks. The Phanerochaete chrysosporium pretreatment was beneficial to the biochar production but exerted an unfavorable effect on the texture structure. The Phanerochaete chrysosporium also had an obvious influence on the bio-oil compositions. This study can provide a scientific reference for the application of biological pretreatment for biomass pyrolysis technology.

Combined effects of polystyrene microplastics and copper on antioxidant capacity, immune response and intestinal microbiota of Nile tilapia (Oreochromis niloticus).

Microplastics (MPs) coexist with other pollutants (such as heavy metals) in water, adversely impacting aquatic organisms, which might cause unpredictable ecological risks. This study aims to evaluate the effect of copper (Cu2+) and polystyrene microplastics (PS-MPs) on antioxidant capacity, immune response and intestinal microbiota of Nile tilapia. Cu2+ and PS-MPs co-exposure enhanced Cu2+ bioaccumulation in the liver of fish compared with Cu2+-alone exposure. Fish exposed to PS-MPs and Cu2+ displayed histopathologic alterations in the liver, intestine and gill. Exposure at low concentrations of Cu2+ in the C0 and CP0 groups can improve antioxidant capacity and immune response, while oxidative damage and inflammation existed in the high concentration of Cu2+ groups. Intestinal microbiota results showed that the diversity and structure were changed by Cu2+ and PS-MPs exposure, and harmful bacterium even increased at high concentration of Cu2+ and PS-MPs exposure groups. All in all, PS-MPs aggravate the accumulation of Cu2+ and lead to perturbations in biological systems of Nile tilapia.

Stereocomplex micelle loaded with paclitaxel for enhanced therapy of breast cancer in an orthotopic mouse model.

Micelles are promising a nano drug carrier for cancer therapy. However, their application is often limited due to the instability of them in vivo. Herein, we reported the development of stereocomplex micelle (SCM) based on amphiphilic dextran-block-polylactide (Dex-b-PLA) that could improve the stability of micelles, reduce the early release of loaded drugs and target the breast cancer through the enhanced permeability and retention (EPR) effect for enhanced breast cancer therapy. The SCM were fabricated from the equimolar mixture of the enantiomeric Dex-b-PLA copolymers. Paclitaxel (PTX) as a model anti breast cancer drug was loaded in the SCM, noted as SCM/PTX. Transmission electron microscopy (TEM) and dynamic laser scattering (DLS) showed the diameter of SCM/PTX was below100 nm, which was suitable sizes for the EPR effect. The release kinetics of SCM/PTX exhibited that the release of PTX was obviously slow down and showed constant release. In the in vitro antitumor test, the SCM/PTX could effectively suppress the viability of 4T1 cells, which was demonstrated by the MTT assay. Moreover, the SCM/PTX could reduce the distribution of PTX at normal organs and obviously increase the accumulation of PTX at tumor sites. The circulation time of SCM/PTX was also obviously enhanced compared to free PTX. In the in vivo antitumor test, the SCM/PTX effectively inhibited the progression of 4T1 breast cancer in the orthotopic mouse model, as demonstrated by decreased tumor growth and increased apoptosis and necrosis areas within tumor tissues. In addition, the toxic side effects of PTX was also alleviated in the SCM/PTX group. This study introduced a stable micelle system that passive targeted the tumor for enhanced breast cancer therapy.

A grazing Gomphotherium in Middle Miocene Central Asia, 10 million years prior to the origin of the Elephantidae.

Feeding preference of fossil herbivorous mammals, concerning the coevolution of mammalian and floral ecosystems, has become of key research interest. In this paper, phytoliths in dental calculus from two gomphotheriid proboscideans of the middle Miocene Junggar Basin, Central Asia, have been identified, suggesting that Gomphotherium connexum was a mixed feeder, while the phytoliths from G. steinheimense indicates grazing preference. This is the earliest-known proboscidean with a predominantly grazing habit. These results are further confirmed by microwear and isotope analyses. Pollen record reveals an open steppic environment with few trees, indicating an early aridity phase in the Asian interior during the Mid-Miocene Climate Optimum, which might urge a diet remodeling of G. steinheimense. Morphological and cladistic analyses show that G. steinheimense comprises the sister taxon of tetralophodont gomphotheres, which were believed to be the general ancestral stock of derived "true elephantids"; whereas G. connexum represents a more conservative lineage in both feeding behavior and tooth morphology, which subsequently became completely extinct. Therefore, grazing by G. steinheimense may have acted as a behavior preadaptive for aridity, and allowing its lineage evolving new morphological features for surviving later in time. This study displays an interesting example of behavioral adaptation prior to morphological modification.

Macrophages mediate corticotomy-accelerated orthodontic tooth movement.

Clinical evidence has suggested that surgical corticotomy of the alveolar bone can accelerate local orthodontic tooth movement (OTM), but the underlying cell and molecular mechanisms remain largely unclear. The present study examined the role of macrophages played in corticotomy-assisted OTM. Orthodontic nickel-titanium springs were applied to the left maxillary first molars of rats or mice to induce OTM with or without corticotomy. Corticotomy enhanced OTM distance by accelerating movement through induction of local osteoclastogenesis and macrophage infiltration during OTM. Further analysis showed that macrophages were polarized toward an M1-like phenotype immediately after corticotomy and then switched to an M2-like phenotype during OTM. The microenvironment of corticotomy induced macrophage infiltration and polarization through the production of TNF-α. More importantly, the amount of OTM induced by corticotomy was significantly decreased after mice were depleted of monocyte/macrophages by injection of liposome-encapsulated clodronate. Further experiments by incubating cultured macrophages with fresh tissue suspension obtained from post-corticotomy gingiva switched the cells to an M1 phenotype through activation of the nuclear factor-κB (NF-κB) signaling pathway, and to an M2 phenotype through activation of the JAK/STAT3 signaling pathway. Our results suggest that corticotomy induces macrophage polarization first by activating the NF-κB signaling pathway and later by activating the JAK/STAT3 signaling pathway, and that these processes contribute to OTM by triggering production of inflammatory cytokines and osteoclastogenesis.

Indication for different mechanisms of kidney uptake of radiolabeled peptides.

UNLABELLED: Nephrotoxicity due to renal reabsorption of radiolabeled peptides limits the tumor dose in peptide receptor radiotherapy (PRRT). Therefore, we evaluated the ability of several agents to inhibit the renal accumulation of different radiopeptides. METHODS: Male Wistar rats (4 per group) were injected intravenously with 1 MBq of (111)In-labeled octreotide (OCT), minigastrin (MG), bombesin (BOM), or exendin (EX), together with a potential inhibitor of renal uptake (lysine [Lys], poly-glutamic acid [PGA], and Gelofusine [GF], a gelatin-based plasma expander) or phosphate-buffered saline as a control. Organ uptake at 20 h after injection was determined as the percentage of injected activity per gram (%IA/g). Lys, PGA, and GF were also combined to determine whether an additive effect could be obtained. The localization of the peptides in the kidneys was investigated by autoradiography using a phosphor imager. RESULTS: OCT accumulation in the kidney was inhibited by Lys and GF (40.7%-45.1%), whereas PGA was ineffective. On the other hand, renal uptake of BOM, MG, and EX was inhibited by PGA and GF (15.4%-85.4%), whereas Lys was ineffective. The combination of GF and Lys showed additive effects in inhibiting OCT uptake, whereas PGA and GF had additive effects for the inhibition of EX uptake. The amount of kidney uptake correlated with the number of charged amino acids. All radiopeptides were localized in the renal cortex, as indicated by autoradiography. CONCLUSION: Inhibition of renal accumulation of the radiopeptides tested could be achieved by either Lys or PGA but not by both at the same time, suggesting 2 different uptake mechanisms. The differences in renal accumulation of radiopeptides may be related to the number of charges of a molecule. GF is the only compound that inhibited renal accumulation of all radiopeptides tested. Additional experiments are needed to further elucidate these findings and to optimize inhibition of renal accumulation of radiopeptides to reduce the kidney dose in PRRT.