Native Niche Research Articles

Identifying Areas of Invasion Risk and Changes in the Ecological Niche Occupied by the Coffee Leaf Miner Leucoptera coffeella (Lepidoptera: Lyonetiidae).

Insects of economic importance such as Leucoptera coffeella can cause high defoliation in plants and reduce crop yields. We aimed to identify changes in the ecological niche and potential zones of the invasion. Occurrence records were obtained from databases and bibliography. WorldClim V2.0 bioclimatic layers were used. For the modeling of the potential distribution, the kuenm R package was used by executing the Maxent algorithm. The potential distribution models suggested greatest environmental suitability extends from Europe, South Asia, and Central and South Africa, showing the "tropical and subtropical moist broadleaf forests" as the ecoregion that presents the greatest probability of the presence of L. coffeella. The potential distribution model projected in the invaded area agrees with the known distribution in the region (America), although the results show that it is occupying environmental spaces not present in the area of origin. This species presented a large proportion of the invaded niche that overlaps the native niche and is colonizing new environmental conditions in the invaded area relative to its native distribution (Africa). This information could be used in the planning of coffee crops on the American continent.

Oral pathobiont Klebsiella chaperon usher pili provide site-specific adaptation for the inflamed gut mucosa

ABSTRACT The ectopic gut colonization by orally derived pathobionts has been implicated in the pathogenesis of various gastrointestinal diseases, including inflammatory bowel disease (IBD). For example, gut colonization by orally derived Klebsiella spp. has been linked to IBD in mice and humans. However, the mechanisms whereby oral pathobionts colonize extra-oral niches, such as the gut mucosa, remain largely unknown. Here, we performed a high-density transposon (Tn) screening to identify genes required for the adaptation of an oral Klebsiella strain to different mucosal sites – the oral and gut mucosae – at the steady state and during inflammation. We find that K. aerogenes, an oral pathobiont associated with both oral and gut inflammation in mice, harbors a newly identified genomic locus named “locus of colonization in the inflamed gut (LIG)” that encodes genes related to iron acquisition (Sit and Chu) and host adhesion (chaperon usher pili [CUP] system). The LIG locus is highly conserved among K. aerogenes strains, and these genes are also present in several other Klebsiella species. The Tn screening revealed that the LIG locus is required for the adaptation of K. aerogenes in its ectopic niche. In particular, we determined K. aerogenes employs a CUP system (CUP1) present in the LIG locus for colonization in the inflamed gut, but not in the oral mucosa. Thus, oral pathobionts likely exploit distinct adaptation mechanisms in their ectopically colonized intestinal niche compared to their native niche.

Modeling the pest-pathogen threats in a warming world for the red turpentine beetle (Dendroctonus valens) and its symbiotic fungus (Leptographium procerum).

Dendroctonus valens along with its symbiotic fungi have caused unprecedented damage to pines in China. Leptographium procerum, its primary symbiotic fungus, facilitates the invasion and colonization of the pest, thereby aggravating ecological threats. Assessing shifts in the niches and ranges of D. valens and its symbiotic fungus could provide a valuable basis for pest control. Here, we conducted niche comparisons between native and invasive populations of D. valens. Then, we employed standard ecological niche models and ensembles of small models to predict the potential distributions of D. valens and L. procerum under climate change conditions and to estimate areas of overlap. The niche of invasive population of D. valens in Chinese mainland only occupied a limited portion of the niche of native population in North America, leaving a substantial native niche unfilled and without any niche expansion. The suitable regions for D. valens are predicted in central and southern North America and central and northeastern Chinese mainland. The overlap with the suitable regions of L. procerum included eastern North America and the central and northeastern Chinese mainland under historical climatic scenarios. The regions susceptible to their symbiotic damage will shift northward in response to future climate change. Projected distributions of D. valens and its symbiotic fungus, along with areas vulnerable to their symbiotic damage, provide essential insights for devising strategies against this association. Additionally, our study contributes to comprehending how biogeographic approaches aid in estimating potential risks of pest-pathogen interactions in forests within a warming world. © 2024 Society of Chemical Industry.

Preparation of Decellularized Tissue as Dual Cell Carrier Systems: A Step Towards Facilitating Re-epithelization and Cell Encapsulation for Tracheal Reconstruction.

Surgical treatment of tracheal diseases, trauma, and congenital stenosis has shown success through tracheal reconstruction coupled with palliative care. However, challenges in surgical-based tracheal repairs have prompted the exploration of alternative approaches for tracheal replacement. Tissue-based treatments, involving the cultivation of patient cells on a network of extracellular matrix (ECM) from donor tissue, hold promise for restoring tracheal structure and function without eliciting an immune reaction. In this study, we utilized decellularized canine tracheas as tissue models to develop two types of cell carriers: a decellularized scaffold and a hydrogel. Our hypothesis posits that both carriers, containing essential biochemical niches provided by ECM components, facilitate cell attachment without inducing cytotoxicity. Canine tracheas underwent vacuum-assisted decellularization (VAD), and the ECM-rich hydrogel was prepared through peptic digestion of the decellularized trachea. The decellularized canine trachea exhibited a significant reduction in DNA content and major histocompatibility complex class II, while preserving crucial ECM components such as collagen, glycosaminoglycan, laminin, and fibronectin. Scanning electron microscope and fluorescent microscope images revealed a fibrous ECM network on the luminal side of the cell-free trachea, supporting epithelial cell attachment. Moreover, the ECM-rich hydrogel exhibited excellent viability for human mesenchymal stem cells encapsulated for 3 days, indicating the potential of cell-laden hydrogel in promoting the development of cartilage rings of the trachea. This study underscores the versatility of the trachea in producing two distinct cell carriers-decellularized scaffold and hydrogel-both containing the native biochemical niche essential for tracheal tissue engineering applications.

An Advanced Bioconjugation Strategy for Covalent Tethering of TGFβ3 with Silk Fibroin Matrices and its Implications in the Chondrogenesis Profile of Human BMSCs and Human Chondrocytes: A Paradigm Shift in Cartilage Tissue Engineering.

The transforming growth factor-β class of cytokines plays a significant role in articular cartilage formation from mesenchymal condensation to chondrogenic differentiation. However, their exogenous addition to the chondrogenic media makes the protocol expensive. It reduces the bioavailability of the cytokine to the cells owing to their burst release. The present study demonstrates an advanced bioconjugation strategy to conjugate transforming growth factor-β3 (TGFβ3) with silk fibroin matrix covalently via a cyanuric chloride coupling reaction. The tethering and change in secondary conformation are confirmed using various spectroscopic analyses. To assess the functionality of the chemically modified silk matrix, human bone marrow-derived mesenchymal stem cells (hBMSCs) and chondrocytes are cultured for 28 days in a chondrogenic differentiation medium. Gene expression and histological analysis reveal enhanced expression of chondrogenic markers with intense Safranin-O and Alcian Blue staining in TGFβ3 conjugated silk matrices than where TGFβ3 is exogenously added to the media for both hBMSCs and chondrocytes. Therefore, this study successfully recapitulates the native niche of TGFβ3 and the role of the silk as a growth factor stabilizer. When cultured over TGFβ3 conjugated silk matrices, hBMSCs display increased proteoglycan secretion and maximum chondrogenic trait with attenuation of chondrocyte hypertrophy over human chondrocytes.

Records of urban occurrences expand estimates of the climate niches in tree species

AbstractAimQuantifying a species' climate niche is often the first step to determining potential sensitivity to climate change. This process typically relies on native occurrence records, assuming that these reflect the breadth of a species' climatic requirements. Yet, many species survive in non‐native regions with climates beyond their native range. Identifying their characteristics could help to better elucidate responses to climate change. Here, we use an extensive data set of urban street tree and native range records for 566 tree species to assess differences between species native and urban climate niches and whether niche differences are predictable given characteristics of species native ranges.LocationGlobal.Time Period1970–2020.Major Taxa StudiedTree species.MethodsMultivariate niche estimations were undertaken using eight climate variables. Calculations included the size of species' urban and native niches, overlap and direction of shift. Relationships between niches and native range attributes (temperature and precipitation breadth, range size, Köppen Geiger subclasses occupied) were calculated using multiple linear regression.Results83% of tree species studied had significantly larger urban niches compared to native niches. Species with narrow geographic ranges demonstrated greater mismatch between their two niches, and the direction of niche shift was associated with their native range Köppen Geiger zone. For example, species native to the wet tropics tend to be planted in cooler, drier urban spaces; those native to cold regions are planted in warmer urban spaces.Main ConclusionNative range occurrences may poorly reflect the breadth of climatic conditions a species can tolerate—particularly for species with narrow geographic ranges. For some species, Köppen Geiger zones may be a useful proxy to help understand sensitivity to climate change. Accounting for possible plasticity in tree species to climate can improve our understanding of their sensitivity and adaptive capacity to climate change.

Climatic niche differentiation between native and non‐native ranges is widespread in Ponto‐Caspian amphipods

Abstract1. Niche conservatism posits that a species' non‐native populations establish in areas that match their native environmental conditions. Although the Ponto‐Caspian biodiversity hotspot is a major source of freshwater alien species, the extent to which their climatic niches diverge between invaded and native ranges remains poorly understood.2. Using an n‐dimensional hypervolume approach, we quantified climatic niche overlap and inferred patterns of niche differentiation (shift, contraction, or expansion) among native and invaded ranges for 12 widespread Ponto‐Caspian amphipod species (six genera in three families).3. Our results show that all species experience substantially different climatic conditions in their invaded range compared to their native range. The invasive niche either contracted (five species), shifted (four species), expanded and shifted (two species), or shifted and contracted (one species) relative to the native niche.4. We conclude that although the focal taxa share a common geographic origin and evolutionary history, they exhibit disparate patterns of climatic niche change outside their native range. The niche conservatism hypothesis receives mixed support given that half of the studied species underwent niche shifts/expansion. Furthermore, congeners exhibited both identical and contrasting patterns of niche differentiation, suggesting a limited phylogenetic effect.5. The uncovered diversity of niche dynamics among closely related species indicates that each has a unique potential for invasiveness and long‐term persistence. This has important implications for predicting invasion risk and refining management strategies. Our study also underlines the importance of biodiversity hotspots as reservoirs of highly adaptable alien species.

Spatial transcriptomic interrogation of the murine bone marrow signaling landscape

Self-renewal and differentiation of skeletal stem and progenitor cells (SSPCs) are tightly regulated processes, with SSPC dysregulation leading to progressive bone disease. While the application of single-cell RNA sequencing (scRNAseq) to the bone field has led to major advancements in our understanding of SSPC heterogeneity, stem cells are tightly regulated by their neighboring cells which comprise the bone marrow niche. However, unbiased interrogation of these cells at the transcriptional level within their native niche environment has been challenging. Here, we combined spatial transcriptomics and scRNAseq using a predictive modeling pipeline derived from multiple deconvolution packages in adult mouse femurs to provide an endogenous, in vivo context of SSPCs within the niche. This combined approach localized SSPC subtypes to specific regions of the bone and identified cellular components and signaling networks utilized within the niche. Furthermore, the use of spatial transcriptomics allowed us to identify spatially restricted activation of metabolic and major morphogenetic signaling gradients derived from the vasculature and bone surfaces that establish microdomains within the marrow cavity. Overall, we demonstrate, for the first time, the feasibility of applying spatial transcriptomics to fully mineralized tissue and present a combined spatial and single-cell transcriptomic approach to define the cellular components of the stem cell niche, identify cell‒cell communication, and ultimately gain a comprehensive understanding of local and global SSPC regulatory networks within calcified tissue.

3D bioprinted tumor-vessel-bone co-culture scaffold for breast cancer bone metastasis modeling and drug testing

Bone metastasis is one of the most common complications of advanced breast cancer (BrCa) with a poor clinical prognosis, due to the lack of effective drugs and therapeutics. Traditional screening systems for anti-cancer drugs are not capable of exactly reflecting the efficacy of drugs in vivo, mainly because they cannot replicate the dynamic metastasis process involving primary tumor, blood circulation and bone microenvironment. To precisely simulate the behavior of native BrCa cells, herein, a biomimetic 3D co-culture metastatic model composed of tumor, hollow vascular, and bone tissues is fabricated by one-step 3D bioprinting method for effective drug testing. Gelatin methacryloyl-based photocrosslinkable bioinks containing breast cancer cells (MDA-MB-231), human umbilical vein endothelial cells (HUVECs) and osteoblasts (h-OB) are applied to highly imitate the native metastatic niches with the formation of blood vessels, vascularized tumors, as well as vascularized bone tissues. The dynamic invasion behavior of BrCa cells from original sites to bone tissues through blood vessels is reproduced, and the interactive effect of cancer, vascular and bone cells are investigated. Moreover, the 3D co-culture metastatic model allows for higher drug resistance of BrCa cells than 2D culture and 3D mono-culture models. These results demonstrate that the 3D bioprinted co-culture metastatic model facilitates in-depth understanding of the basic mechanisms of BrCa migration and provides a physiologically relevant platform for the development of new therapeutic drugs.

Traceless Protein-Selective Glycan Labeling and Chemical Modification.

Executing glycan editing at a molecular level not only is pivotal for the elucidation of complicated mechanisms involved in glycan-relevant biological processes but also provides a promising solution to potentiate disease therapy. However, the precision control of glycan modification or glyco-editing on a selected glycoprotein is by far a grand challenge. Of note is to preserve the intact cellular glycan landscape, which is preserved after editing events are completed. We report herein a versatile, traceless glycan modification methodology for customizing the glycoforms of targeted proteins (subtypes), by orchestrating chemical- and photoregulation in a protein-selective glycoenzymatic system. This method relies on a three-module, ligand-photocleavable linker-glycoenzyme (L-P-G) conjugate. We demonstrated that RGD- or synthetic carbohydrate ligand-containing conjugates (RPG and SPG) would not activate until after the ligand-receptor interaction is accomplished (chemical regulation). RPG and SPG can both release the glycoenzyme upon photoillumination (photoregulation). The adjustable glycoenzyme activity, combined with ligand recognition selectivity, minimizes unnecessary glycan editing perturbation, and photolytic cleavage enables precise temporal control of editing events. An altered target protein turnover and dimerization were observed in our system, emphasizing the significance of preserving the native physiological niche of a particular protein when precise modification on the carbohydrate epitope occurs.

Perivascular invasion of primary human glioblastoma cells in organotypic human brain slices: human cells migrating in human brain.

Glioblastoma (GBM) is an aggressive primary brain cancer. Lack of effective therapy is related to its highly invasive nature. GBM invasion has been studied with reductionist systems that do not fully recapitulate the cytoarchitecture of the brain. We describe a human-derived brain organotypic model to study the migratory properties of GBMIDH-wild type ex vivo. Non-tumor brain samples were obtained from patients undergoing surgery (n = 7). Organotypic brain slices were prepared, and green fluorescent protein (GFP)-labeled primary human GBM IDH-wild type cells (GBM276, GBM612, GBM965) were placed on the organotypic slice. Migration was evaluated via microscopy and immunohistochemistry. After placement, cells migrated towards blood vessels; initially migrating with limited directionality, sending processes in different directions, and increasing their speed upon contact with the vessel. Once merged, migration speed decreased and continued to decrease with time (p < 0.001). After perivascular localization, migration is limited along the blood vessels in both directions. The percentage of cells that contact blood vessels and then continue to migrate along the vessel was 92.5% (-3.9/ + 2.9)% while the percentage of cells that migrate along the blood vessel and leave was 7.5% (-2.9/ + 3.9) (95% CI, Clopper-Pearson (exact); n = 256 cells from six organotypic cultures); these percentages are significantly different from the random (50%) null hypothesis (z = 13.6; p < 10-7). Further, cells increase their speed in response to a decrease in oxygen tension from atmospheric normoxia (20% O2) to anoxia (1% O2) (p = 0.033). Human organotypic models can accurately study cell migrationex vivo. GBM IDH-wild type cells migrate toward the perivascular space in blood vessels and their migratory parameters change once they contact vascular structures and under hypoxic conditions. This model allows the evaluation of GBM invasion, considering the human brain microenvironment when cells are removed from their native niche after surgery.

Patterns and drivers of climatic niche dynamics during biological invasions of island-endemic amphibians, reptiles, and birds.

Shifts between native and alien climatic niches pose a major challenge for predicting biological invasions. This is particularly true for insular species because geophysical barriers could constrain the realization of their fundamental niches, which may lead to underestimates of their invasion potential. To investigate this idea, we estimated the frequency of shifts between native and alien climatic niches and the magnitude of climatic mismatches using 80,148 alien occurrences of 46 endemic insular amphibian, reptile, and bird species. Then, we assessed the influence of nine potential predictors on climatic mismatches across taxa, based on species' characteristics, native range physical characteristics, and alien range properties. We found that climatic mismatch is common during invasions of endemic insular birds and reptiles: 78.3% and 55.1% of their respective alien records occurred outside of the environmental space of species' native climatic niche. In comparison, climatic mismatch was evident for only 16.2% of the amphibian invasions analyzed. Several predictors significantly explained climatic mismatch, and these varied among taxonomic groups. For amphibians, only native range size was associated with climatic mismatch. For reptiles, the magnitude of climatic mismatch was higher for species with narrow native altitudinal ranges, occurring in topographically complex or less remote islands, as well as for species with larger distances between their native and alien ranges. For birds, climatic mismatch was significantly larger for invasions on continents with higher phylogenetic diversity of the recipient community, and when the invader was more evolutionarily distinct. Our findings highlight that apparently common niche shifts of insular species may jeopardize our ability to forecast their potential invasions using correlative methods based on climatic variables. Also, we show which factors provide additional insights on the actual invasion potential of insular endemic amphibians, reptiles, and birds.

Hydrogels provide microenvironments to mesenchymal stem cells for craniofacial bone regeneration: Review.

The anatomical and physiological architecture of the craniofacial bone is intricate. Hence, the exact management of osteogenesis is necessary for the regeneration of the deficiencies that present in this area. Stem-based tissue engineering approaches, as opposed to conventional surgical intervention, induce bone growth with minimal postoperative risk and expense. Mesenchymal stem/stromal cells (MSC)'s pluripotent differentiation potential, anti-inflammatory and immunomodulatory properties underpin its versatility as a therapeutic agent in bone tissues. Inspired by the native stem cell niche, hydrogels are preferred choices to mediate cells and adapt to 3-D environment because of their outstanding swelling capabilities and similarity to natural extracellular matrices (ECMs). Due to their remarkable biocompatibility and capacity for stimulating bone regeneration, bone regeneration hydrogels have also received a great deal of interest. This review explores the opportunities of MSC based regenerative skeletal therapies, introduces the application of hydrogel scaffolds as artificial bone microenvironments for stem cells to explore its usage in craniofacial bone tissue engineering.

The regulation of tendon stem cell distribution, morphology, and gene expression by the modulus of microfibers

The mechanical properties of a stem cell culture substrate significantly impact cell adhesion, survival, migration, proliferation, and differentiation in vitro. A major challenge in engineering artificial stem cell substrate is to properly identify the relevant physical features of native stem cell niches, which are likely different for each stem cell type. The behavior of tendon stem cells has potentially significant implications for tendon repair. Here, microfiber scaffolds with various modulus of elasticity are fabricated by near-field electrospinning, and their regulating effects on the in vitro behavior of tendon stem cells (TSCs) are discussed in this study. The number of pseudopodia shows a biphasic relationship with the modulus of scaffold. The proliferation, polarization ratio and alignment degree along the fibers of the TSCs increase with the increase of fiber modulus. TSCs cultured on the scaffold with moderate modulus (1429 MPa) show the upregulation of tendon-specific genes (Col-I, Tnmd, SCX and TNCF). These microfiber scaffolds provide great opportunities to modulate TSCs behavior at the micrometer scales. In conclusion, this study provides an instructive mechanical microenvironment for TSCs behaviors and may lead to the development of desirable engineered artificial stem cell substrate for tendon healing.

Multidimensional climatic niche conservatism and invasion risk of Phenacoccus solenopsis.

The cotton mealybug Phenacoccus solenopsis, a globally invasive insect, is listed as a national quarantine pest in agriculture and forestry, which seriously threatens biological safety of China. Niche conservatism is a key assumption of species distribution model. An evaluation of the applicability of using ecological niche models to assess the invasion risk of cotton mealybug, and further optimizing model complexity, are of both theoretical and practical significance. Based on 706 occurrence records and key bioclimatic variables, we used n-dimensional hypervolume niche analysis method to quantify the climatic niche hypervolumes of this pest in both native and invasive sites, and further tested the niche conservatism hypothesis. MaxEnt model parameters were optimized to predict the invasion risk of the mealybug under current and future climate scenarios in China. The results showed that four climatic variables (annual mean temperature, mean temperature of wettest quarter, mean temperature of warmest quarter, and precipitation of driest quarter) were the key climate factors affecting the distribution of cotton mealybug. Compared with native climatic niche (hypervolume volume, HV=40.43), the niche hypervolume of cotton mealybug in the invasive areas was significantly reduced (HV=6.04). Niche contraction (the net differences between the amount of space enclosed by each hypervolume was 0.84) explained 98.8% of niche differentiation, whereas niche shift (the replacement of space between hypervolumes was 0.01) contributed less than 2%. The direction of climatic niche contraction of the pest in different invasive areas was not exactly consistent. The default parameters of MaxEnt model were unreliable (ΔAICc=14.27), and the optimal parameter combination was obtained as follows: feature combination was linear-quadratic-hinge-product and regularization multiplier was 0.5. The most suitable habitats of cotton mealybug were concentrated in the south of Huaihe River-Qinling Mountains line, and the north-central provinces contained a large area of low suitable habitat. The increase of suitable habitat was not significant at the end of 21 century (SSP1-2.6: 1.7%, SSP5-8.5: 0.7%). The multidimensional climatic niche of P. solenopsis was highly conservative. The species distribution model was suitable for analyzing its invasion risk. The northward spread was obvious, and climate change had less impact on the pest.

Patient-derived MicroOrganoSpheres (MOS) and precision clinical decision-making for patients with multiple myeloma.

8047 Background: There are many multiple myeloma (MM) treatments and nearly all patients undergo continual cycles of treatment, response, and resistance. Selecting an effective therapeutic strategy is of critical importance; but there is currently a lack of patient-derived MM models that can enable functional precision medicine to help real-time clinical decision-making to guide individual patient treatment. Methods: We show a method to rapidly establish MM patient-derived MicroOrganoSheres (MOS), which are microscale, droplet-sized patient avatars that sustain the native tumor niche, including both stromal and immune compartments. We generated first-of-its-kind data showing that MM MOS predicted patient treatment outcomes and have the potential to guide clinical treatment decisions. We further developed high-throughput drug screen to demonstrate MM MOS response to FDA-approved single and combination therapies and developed MOS assays to predict patient responses to immunotherapies including bispecific and phagocytosis-inducing antibodies. Results: MM MOS established from patient bone marrow (BM) biopsies preserved CD138/CD38 tumor cells, stromal (e.g., osteoblast) cells, and all major immune cell populations (T, NK, B, macrophage, dendritic, and myeloid-derived suppressor cells) for 11 days in culture. We performed single and combo drug testing on MOS derived from 7 MM patients within 10 days of biopsy collection. Patients went on receiving treatments and their responses were assessed using International Myeloma Working Group response criteria. The MOS assay predicted responses of both treatment-naïve and refractory patient to standard-of-care regimens, including combinations of proteasome inhibitors (bortezomib, carfilzomib), immunomodulatory agents (lenalidomide) and DCEP. Moreover, the BM biopsy-derived MOS enabled high-throughput drug testing of single agents and combinations in 9-dose titrations, providing clinicians the ability to evaluate alternative treatment options. Furthermore, because MOS retain the immune compartments of the original tumor niche, we were able to evaluate patients’ response to bispecific T cell engagers and developed a phagocytosis assay to measure anti-tumor phagocytosis activity, which showed efficacy in both single-agent and combo settings. Multi-modal profiling and an AI image analysis pipeline provided robust measurements that confirmed the unique phenotypic profile of each patient sample, highlighting the critical unmet need to guide each patient to the optimal treatment. Conclusions: Based on this groundbreaking feasibility study, a subsequent clinical trial of 40 patients is current under IRB review to further validate the clinical power of MM MOS to predict patient outcome and to demonstrate utility as a viable functional precision medicine approach to inform treatment decisions in the clinic.

Regional anthropogenic disturbance and species-specific niche traits influence the invasiveness of European beetle species

Coleoptera are key elements of terrestrial trophic interactions and generate significant economic and ecological benefits, but their representatives also represent severe pest species. Understanding how invasive species operate is indispensable to identify and anticipate potential invasion areas. However, few studies have explored niche dynamics and drivers of invasions in this group. Here we examined niche dynamics across 54 invasive beetle species native to Europe and assessed whether factors such as human influence index, feeding habits, body size, and niche breadth are associated with the degree of invasion. The realized niches had low similarity in invasive and native ranges (i.e., invaded areas are climatically dissimilar to native ranges). This included a high degree of niche expansion in invaded areas but also environments occupied in the native ranges but unoccupied in the invasive range (unfilling), suggesting that altered species–climate relationships during invasion processes are common. Niche expansions showed positive association with small native niche breadth sizes and movements from highly disturbed native areas to less disturbed invaded ranges; unfilling was associated with invaded niche breadth size and frequency of species occurrence. Both were related to dissimilar realized climatic niches in invaded ranges. Colonization of invaded areas might be triggered by low quality resources in native areas. Unfilling levels might be related to the year of introduction and loss of biotic constraints present in their native distribution, leading to the use of different climatic spaces in the invasive areas. This idea is reinforced by larger invasive climatic niche breadth. Our results provide insight into patterns of invasive species, and initial holistic exploration towards the understanding of invasive species dynamics.

In Vitro and In Vivo Improvement of Islet Quality and Transplantation Successes following Islet Treatment with Biomaterials in Diabetic Rats.

Loss of islet survival and function, caused by native niche disruption and oxidative stress induction during mechanical and enzymatic isolation, limits the effectiveness of islet transplantation. Reconstitution of islet microenvironment, vascularization, and decreased oxidative stress with biomaterials may improve islet quality and graft outcomes. We investigated effects of two biomaterials, platelet-rich plasma and pancreatic islets homogenate combination on islet recovery and quality by evaluating in vitro islet survival, secretory function, and oxidative stress parameters and assessing in vivo transplantation outcomes. In vitro, islet viability and secretory function of isolated islets were assessed after 24 h and 72 h incubation with biomaterials. Also, oxidative stress markers were measured once after isolation and 24 h after incubation with biomaterials. For evaluating in vivo effects, cultured islets for 24 h were transplanted into subscapular space of diabetic rat kidney, and outcomes were analyzed by measuring serum glucose and insulin concentrations, glucose tolerance test, level of oxidative parameters, and pancreatic gene expression. Treating islets with biomaterials significantly increased their viability and secretory function, reduced MDA level, and elevate SOD and CAT activity. Decreased level of glucose and MDA improved insulin level, increased SOD activity, and also enhanced pdx1 and insulin gene expression in diabetic rats after islet transplantation. Biomaterials used in the present study should be consider as beneficial materials for increasing islet transplantation outcome. These materials may hamper transplantation limitation to some extent.

Bone-on-a-Chip: Biomimetic Models Based on Microfluidic Technologies for Biomedical Applications.

With the increasing importance of preclinical evaluation of newly developed drugs or treatments, in vitro organ or disease models are necessary. Although various organ-specific on-chip (organ-on-a-chip, or OOC) systems have been developed as emerging in vitro models, bone-on-a-chip (BOC) systems that recapitulate the bone microenvironment have been less developed or reviewed compared with other OOCs. The bone is one of the most dynamic organs and undergoes continuous remodeling throughout its lifetime. The aging population is growing worldwide, and healthcare costs are rising rapidly. Since in vitro BOC models that recapitulate native bone niches and pathological features can be important for studying the underlying mechanism of orthopedic diseases and predicting drug responses in preclinical trials instead of in animals, the development of biomimetic BOCs with high efficiency and fidelity will be accelerated further. Here, we review recently engineered BOCs developed using various microfluidic technologies and investigate their use to model the bone microenvironment. We have also explored various biomimetic strategies based on biological, geometrical, and biomechanical cues for biomedical applications of BOCs. Finally, we addressed the limitations and challenging issues of current BOCs that should be overcome to obtain more acceptable BOCs in the biomedical and pharmaceutical industries.

Biomimetic Periodontal Ligament Transplantation Activated by Gold Nanoparticles Protects Alveolar Bone.

Stem cell therapy might be a promising method to stimulate alveolar bone regeneration, which is currently a major clinical challenge. However, its therapeutic features largely depend on pretreatment and transplantation preparation. Herein, a novel biomimetic periodontal ligament transplantation composed of human periodontal ligament stem cells (hPDLSCs) pretreated with gold nanocomplexes (AuNCs) and embedded in a type-I collagen hydrogel scaffold is developed to protect alveolar bone from resorption. AuNCs are readily absorbed by primary hPDLSCs, with limited cytotoxicity, and promote osteogenic differentiation of hPDLSCs effectively in vitro. In addition, the AuNCs-induced hPDLSCs are encapsulated with type-I collagen hydrogel scaffold to mimic their native physiological niche, and then are transplanted into a rat model of alveolar bone resorption. Both micro-computed tomography (micro-CT) and immunohistochemical assays demonstrate that alveolar bone loss is significantly prevented. Furthermore, the underlying therapeutic mechanism is elucidated, in which transplantation-activated osteogenesis is associated with autophagy, which enables bone remodeling and regeneration. This study provides critical insight into the role of PDLSCs in bone homeostasis and proposes an innovative AuNCs-based strategy for stem cell therapy in bone regeneration.