FABP4-mediated lipid accumulation and lipolysis in tumor associated macrophages promote breast cancer metastasis.

A high density of tumor-associated macrophages (TAMs) is associated with poorer prognosis and survival in breast cancer patients. Recent studies have shown that lipid accumulation in TAMs can promote tumor growth and metastasis in various models. However, the specific molecular mechanisms that drive lipid accumulation and tumor progression in TAMs remain largely unknown. Herein, we demonstrated that unsaturated fatty acids (FAs), unlike saturated ones, are more likely to form lipid droplets in macrophages. Specifically, unsaturated FAs, including linoleic acids (LA), activate the FABP4/CEBPα pathway, leading to triglyceride synthesis and lipid droplet formation. Furthermore, FABP4 enhances lipolysis and FA utilization by breast cancer cells, which promotes cancer cell migration in vitro and metastasis in vivo . Notably, a deficiency of FABP4 in macrophages significantly reduces LA-induced lipid metabolism. Therefore, our findings suggest FABP4 as a crucial lipid messenger that facilitates unsaturated FA-mediated lipid accumulation and lipolysis in TAMs, thus contributing to the metastasis of breast cancer. Highlights: Unlike saturated fatty acids, unsaturated fatty acids preferentially promote lipid droplet formation in macrophages.Unsaturated fatty acids activate the FABP4/CEBPα axis for neutral lipid biosynthesis in macrophagesDeficiency of FABP4 compromised unsaturated fatty acid-mediated lipid accumulation and utilization in macrophagesFABP4-mediated lipid metabolism in macrophages contributes to breast cancer metastasis.

Determination of the FABP5 expression profile in skin lesions of an IMQ-induced psoriasis mouse model using flow cytometry.

The fatty acid-binding protein 5 (FABP5) is a key player in psoriasis development. Therefore, characterizing the expression profile of FABP5 in various cell types within both layers of psoriatic skin is important. Here, we present a protocol that describes steps for an imiquimod-induced psoriasis mouse model and preparation of epidermal and dermal single-cell suspensions. We then detail procedures to detect the FABP5 expression profile in skin keratinocytes and immune cells using intracellular flow cytometry staining. For complete details on the use and execution of this protocol, please refer to Hao et al.1.

Surface Modification of Silicon Nanowires with Siloxane Molecules for High-Performance Hydrovoltaic Devices.

Hydrovoltaic devices (HDs) based on silicon nanowires (SiNWs) have attracted significant attention due to their potential of high output power and good compatibility with Si-based photovoltaic devices for integrated power systems. However, it remains a major challenge to further improve the output performance of SiNW HDs for practical applications. Here, a new strategy to modify the surface of SiNWs with siloxane molecules is proposed to improve the output performance of the SiNW HDs. After modification, both the open-circuit voltage (Voc) and short-circuit current density (Jsc) of n-type SiNW HDs can be improved by approximately 30%, while the output power density can be greatly increased by over 200%. With siloxane modification, Si-OH groups on the surface of typical SiNWs are replaced by Si-O-Si chemical bonds that have a weaker electron-withdrawing capability. More free electrons in n-type SiNWs are liberated from surface bound states and participate in directed flow induced by water evaporation, thereby improving the output performance of HDs. The improved performance is significant for system integration applications as it reduces the number of required devices. Three siloxane-modified SiNW HDs in series are able to drive a 2 V light-emitting diode (LED), whereas four unmodified devices in series are initially needed for the same task. This work provides a simple yet effective strategy for surface modification to improve the output performance of SiNW HDs. Further research into the effect of different surface modifications on the performance of SiNW HDs will greatly promote their performance enhancement and practical applications.

Cytological evidence of BSD2 functioning in both chloroplast division and dimorphic chloroplast formation in maize leaves.

BACKGROUND: Maize bsd2 (bundle sheath defective2) is a classical C4 mutant with defective C4 photosynthesis, accompanied with reduced accumulation of Rubisco (ribulose bisphosphate carboxylase oxygenase) and aberrant mature chloroplast morphology in the bundle sheath (BS) cells. However, as a hypothetical chloroplast chaperone, the effects of BSD2 on C4 chloroplast development have not been fully examined yet, which precludes a full appreciation of BSD2 function in C4 photosynthesis. The aims of our study are to find out the role ofBSD2 in regulating chloroplasts development in maize leaves, and to add new insights into our understanding of C4 biology. RESULTS: We found that at the chloroplast maturation stage, the thylakoid membranes of chloroplasts in the BS and mesophyll (M) cells became significantly looser, and the granaof chloroplasts in the M cells became thinner stacking in the bsd2 mutant when compared with the wildtype plant. Moreover, at the early chloroplast development stage, the number of dividing chloroplasts and the chloroplast division rate are both reduced in the bsd2 mutant, compared with wild type. Quantitative reverse transcriptase-PCR analysis revealed that the expression of both thylakoid formation-related genesand chloroplast division-related genes is significantly reduced in the bsd2 mutants. Further, we showed that BSD2 interacts physically with the large submit of Rubisco (LS) in Bimolecular Fluorescence Complementation assay. CONCLUSIONS: Our combined results suggest that BSD2 plays an essential role in regulating the division and differentiation of the dimorphic BS and M chloroplasts, and that it acts at a post-transcriptional level to regulate LS stability or assembly of Rubisco.

Gibberellin indirectly promotes chloroplast biogenesis as a means to maintain the chloroplast population of expanded cells.

Chloroplast biogenesis needs to be well coordinated with cell division and cell expansion during plant growth and development to achieve optimal photosynthesis rates. Previous studies showed that gibberellins (GAs) regulate many important plant developmental processes, including cell division and cell expansion. However, the relationship between chloroplast biogenesis with cell division and cell expansion, and how GA coordinately regulates these processes, remains poorly understood. In this study, we showed that chloroplast division was significantly reduced in the GA-deficient mutants of Arabidopsis (ga1-3) and Oryza sativa (d18-AD), accompanied by the reduced expression of several chloroplast division-related genes. However, the chloroplasts of both mutants exhibited increased grana stacking compared with their respective wild-type plants, suggesting that there might be a compensation mechanism linking chloroplast division and grana stacking. A time-course analysis showed that cell expansion-related genes tended to be upregulated earlier and more significantly than the genes related to chloroplast division and cell division in GA-treated ga1-3 leaves, suggesting the possibility that GA may promote chloroplast division indirectly through impacting leaf mesophyll cell expansion. Furthermore, our cellular and molecular analysis of the GA-response signaling mutants suggest that RGA and GAI are the major repressors regulating GA-induced chloroplast division, but other DELLA proteins (RGL1, RGL2 and RGL3) also play a role in repressing chloroplast division in Arabidopsis. Taken together, our data show that GA plays a critical role in controlling and coordinating cell division, cell expansion and chloroplast biogenesis through influencing the DELLA protein family in both dicot and monocot plant species.

Multiphoton microscopic imaging of in vivo hair mouse skin based on two-photon excited fluorescence and second harmonic generation.

Mouse is an important animal model to investigate skin physiological and pathological states. In this article, multiphoton microscopic imaging of in vivo hair mouse skin based on two-photon excited fluorescence and second harmonic generation was examined. Our results show that multiphoton microscopy can clearly display microstructure of stratum corneum, stratum spinosum, and dermis of in vivo mouse skin. The main components of epidermis and dermis such as corneocytes, spinosum cell, collagen fibers, and hair follicles can be distinctly identified in MPM images. Using the optional HRZ 200 fine focusing stage, thickness of different layers can be easily assessed. The results demonstrate that MPM can be regarded as an efficient method for in vivo investigation of skin physiological and pathological states by using hair mouse animal model.

Multiphoton microscopy study of the morphological and quantity changes of collagen and elastic fiber components in keloid disease.

Multiphoton microscopy was used to study the extracellular matrix of keloid at the molecular level without tissue fixation and staining. Direct imaging of collagen and elastin was achieved by second harmonic generation and two-photon excited fluorescence, respectively. The morphology and quantity of collagen and elastin in keloid were characterized and quantitatively analyzed in comparison to normal skin. The study demonstrated that in keloid, collagen content increased in both the upper dermis and the deep dermis, while elastin mostly showed up in the deep dermis and its quantity is higher compared to normal skin. This suggests the possibility that abnormal fibroblasts synthesized an excessive amount of collagen and elastin at the beginning of keloid formation, corresponding to the observed deep dermis, while after a certain time point, the abnormal fibroblast produced mostly collagen, corresponding to the observed upper dermis. The morphology of collagen and elastin in keloid was disrupted and presented different variations. In the deep dermis, elastic fibers showed node structure, while collagen showed obviously regular gaps between adjacent bundles. In the upper dermis, collagen bundles aligned in a preferred direction, while elastin showed as sparse irregular granules. This new molecular information provided fresh insight about the development process of keloid.

Label-free discrimination of normal and fibroadenomal breast tissues using second harmonic generation imaging.

Early detection of fibroadenoma (FA) is critical for preventing subsequent breast cancer. In this work, we show that label-free second harmonic generation (SHG) imaging is feasible and effective in quantitatively differentiating the fibroadenomal tissue from normal breast tissue. With the advent of the clinical portability of miniature SHG microscopy, we believe that the technique has great potential in offering a noninvasive in vivo imaging tool for early detection of FA and monitoring the treatment responses of FA in clinics.

Quantification of scar margin in keloid different from atrophic scar by multiphoton microscopic imaging.

Multiphoton microscopy (MPM) was applied to examine the marginal region at dermis of keloid compared with atrophic scar. High-resolution large-area image showed an obvious boundary at the scar margin and different morphological patterns of elastin and collagen on the two sides, further visualized by the focused three-dimensional images. Content alteration of elastin or collagen between the two sides of boundary was quantified to show significant difference between keloid and atrophic scar. Owing to the raised property of keloid with overproduced collagen on the scar side, the content alteration was positive for elastin and negative for collagen. On the contrary, the content alteration was negative for elastin and positive for collagen in the atrophic scar case due to the atrophic collagen on the scar side. It indicated that examination of the scar margin by MPM may lead a new way to discriminate different types of scars and better understand the scarring mechanisms.

Establishing diagnostic features for identifying the mucosa and submucosa of normal and cancerous gastric tissues by multiphoton microscopy.

BACKGROUND: Establishing diagnostic features is essential and significant for developing multiphoton endoscopy to make an early diagnosis of gastric cancer at the cellular level. Until now, these diagnostic features have not been clearly described and understood. DESIGN: Study of diagnostic features based on multiphoton microscopy (MPM). OBJECTIVE: Establishing diagnostic features to identify the mucosa and submucosa of human normal and cancerous gastric tissues by investigating their multiphoton microscopic images. SETTING: Fujian Normal University and Fujian Provincial Tumor Hospital. PATIENTS: Ten pairs of normal and cancerous specimens were obtained from 10 patients (ages 51-68 years) undergoing radical gastrectomy. INTERVENTIONS: MPM was performed on specimens. MAIN OUTCOME MEASUREMENTS: Establishment of diagnostic features. RESULTS: MPM has the ability to exhibit not only the mucosal and submucosal microstructures of normal and cancerous gastric tissues but also the distribution and content of abnormal cells in these 2 layers. More importantly, it can provide the diagnostic features to qualitatively and quantitatively differentiate between normal and cancerous gastric tissues. LIMITATIONS: The selection bias and preparation of specimen. CONCLUSIONS: These findings provide the groundwork for further establishing diagnostic criteria.

Label-free monitoring of colonic cancer progression using multiphoton microscopy.

Real-time histology or virtual biopsy for the diagnosis of colonic cancer is of great medical significance. In this work, we show that label-free multiphoton imaging is feasible and effective in monitoring colonic cancer progression by providing cellular and subcellular details in fresh, unfixed, unstained colonic specimens. Our results also demonstrate the capability of using tissue quantitative analysis of the redox ratio for quantifying colonic cancer progression. These results suggest that multiphoton microscopy has potential to become an in situ histological tool, which is free from the labeling requirement of conventional methods, for the early diagnosis and detection of malignant lesions in the colon.

Two-photon fluorescence and second-harmonic generation imaging of collagen in human tissue based on multiphoton microscopy.

Multiphoton microscopic imaging of collagen plays an important role in noninvasive diagnoses of human tissue. In this study, two-photon fluorescence and second-harmonic generation (SHG) imaging of collagen in human skin dermis and submucosa of colon and stomach tissues were investigated based on multiphoton microscopy (MPM). Our results show that multiphoton microscopic image of collagen bundles exhibits apparently different pattern in human tissues. The collagen bundles can simultaneously reveal its SHG and two-photon excited fluorescence images in the submucosa of colon and stomach, whereas it solely emit SHG signal in skin dermis. The intensity spectral information from tissues further demonstrated the above results. This indicates that collagen bundles have completely different space arrangement in these tissues. Our experimental results bring more detailed information of collagen for the application of MPM in human noninvasive imaging.

Characteristics of scar margin dynamic with time based on multiphoton microscopy.

Scar margins dynamic with time were quantitatively characterized using multiphoton microscopy (MPM). 2D large-area and 3D focused images of elastin and collagen at scar margins were obtained to extract quantitative parameters. An obvious boundary was observed at the scar margin, showing altered morphological patterns of elastin and collagen on both sides. Content alteration of elastin and collagen between the two sides of boundary were defined to characterize scar margins from different individuals. The statistical results from 15 normal scar samples strongly demonstrated that content alteration degree of elastin and collagen had decreasing tendency with the increase of patient age or scar duration, consistent with the fact of normal scars regressing spontaneously over time. It indicated that alteration degree can potentially serve as quantitative indicators to examine wound healing and scar progression over time. With the advent of clinical portable multiphoton endoscopes, the MPM technique can be applied in tracking scar formation and progression in vivo by examination of scar margin.

Multiphoton microscopic imaging of normal human rectum tissue.

In this paper, multiphoton microscopy (MPM), based on two-photon excited fluorescence and second harmonic generation signals, was used to image microstructures of human rectal mucosa and submucosa. The morphology and distribution of the main components in mucosa layer, goblet cells, intestinal glands, and a little collagen fibers have been clearly monitored, and the content and distribution of collagen, elastic fibers, and blood vessels in submucosa layer have also been distinctly obtained. The variation of these components is very relevant to the pathology in gastrointestinal system, especially early rectal cancer. Our results indicate that the MPM technique has the potential application in vivo in the clinical diagnosis and monitoring of early rectal cancer.

Stromal optical properties: differentiating normal and cancerous stroma.

This work reports on the measurement of optical properties from nine normal and cancerous human esophageal stroma pairs using reflectance-based confocal microscopy. It was found that the scattering coefficient of cancerous stroma is significantly lower than that of normal stroma. The results suggest that the decreased scattering in cancerous stroma may provide a possible indicator for differentiating normal and cancerous stroma.

Monitoring dermal wound healing after mesenchymal stem cell transplantation using nonlinear optical microscopy.

Nonlinear optical microscopy (NLOM) was applied for monitoring dermal wound healing after mesenchymal stem cell (MSC) transplantation. Our results showed that NLOM can reveal different regeneration processes of collagen in nontreated and MSC-treated wound dermis. Specifically, the temporal increases in the intensity of second-harmonic-generation signals can quantify kinetic properties of collagen regeneration. Orientation analysis of collagen fiber bundles can monitor the formation of new normal collagen fiber bundles, which is an indicator for evaluating the therapy response. It was also found that NLOM can track MSCs' location and recruitment. These findings suggested that NLOM is ideal for monitoring the progress of dermal wound healing.

Quantified characterization of human cutaneous normal scar using multiphoton microscopy.

The morphological alterations of human cutaneous normal scar were quantitatively analyzed using multiphoton microscopy (MPM) based on two-photon excited fluorescence and second harmonic generation. High-contrast, high-resolution images of normal scar and uninjured skin were obtained for comparison. In addition, some quantitative parameters have been extracted to quantitatively discriminate between normal scar and uninjured skin. The MPM combined with quantitative method enable a better understanding of microstructual alterations of the epidermis, elastic fiber, and collagen in normal scar. It may lead the way to making know the mechanism of normal scar formation and identifying feasible therapeutic options.

Multiphoton laser scanning microscopy of localized scleroderma.

BACKGROUND/PURPOSE: A real-time, non-invasive method will confer a benefit for the diagnosis and treatment of localized scleroderma (LS) in the clinic. The aim of this work was to demonstrate the potential of multiphoton laser scanning microscopy (MPLSM) for diagnosing LS and monitoring the treatment response in vivo. METHODS: Three sclerodermatous skin specimens and two normal skin specimens were investigated using MPLSM based on two-photon excitation fluorescence (TPEF) and second harmonic generation (SHG). MPLSM consists of a femtosecond Ti:sapphire laser and a scanning inverted microscope. Several parameters such as the epidermal thickness, the orientation ratio index of collagen bundles (ORICB), the spacing of collagen fibrin as well as the SHG to TPEF index of the dermis (STID) were developed to quantitatively discriminate the sclerodermatous skin from the normal skin. RESULTS: The morphological differences were visualized obviously in the TPEF/SHG images of human skin (normal and sclerodermatous). The values of the developed parameters in normal skin were significantly different from that in sclerodermatous skin (P<0.05). CONCLUSION: MPLSM could discriminate the sclerodermatous skin from the normal skin. With the advent of the clinical portability of typical MPLSM, this technique has great potential for application in the in vivo diagnosis of LS as well as for monitoring the treatment response.

Jadassohn-Pellizzari anetoderma: study of multiphoton microscopy based on two-photon excited fluorescence and second harmonic generation.

Anetoderma is a rare skin disease with loss of dermal elastic tissue resulting in clinically localized areas of flaccid or herniated sack-like skin. In this study, we report a case of Jadassohn-Pellizzari anetoderma, in a 21-year-old Chinese female with an 18-year history of progressively generalized wrinkled skin lesions. Multiphoton microscopy based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) was firstly employed to investigate the pathological process from unaffected skin to the erythematous phase and finally with affected skin of this case. The results showed that the normal elastic fibers in unaffected skin were almost completely absent in erythematous skin tissue, then replaced by a lot of elastic fibers with granular morphology in affected skin, which was consistent with the histopathological results. The obvious changes in collagen fibers and the occurrence of inflammatory cell infiltration in erythematous tissue suggested that the variations of these two components were also the main pathogenesis of anetoderma, except for the deficiency of elastic fibers. Based on these data, we demonstrated that multiphoton microscopy was a promising tool for non-invasive investigation of the pathology of anetoderma at nearly histological resolution, and has potential for observing the dermatological dynamic processes for living specimens because it is based on the intrinsic signals of tissue components.

Abnormal physiological and molecular mutant phenotypes link chloroplast polynucleotide phosphorylase to the phosphorus deprivation response in Arabidopsis.

A prominent enzyme in organellar RNA metabolism is the exoribonuclease polynucleotide phosphorylase (PNPase), whose reversible activity is governed by the nucleotide diphosphate-inorganic phosphate ratio. In Chlamydomonas reinhardtii, PNPase regulates chloroplast transcript accumulation in response to phosphorus (P) starvation, and PNPase expression is repressed by the response regulator PSR1 (for PHOSPHORUS STARVATION RESPONSE1) under these conditions. Here, we investigated the role of PNPase in the Arabidopsis (Arabidopsis thaliana) P deprivation response by comparing wild-type and pnp mutant plants with respect to their morphology, metabolite profiles, and transcriptomes. We found that P-deprived pnp mutants develop aborted clusters of lateral roots, which are characterized by decreased auxin responsiveness and cell division, and exhibit cell death at the root tips. Electron microscopy revealed that the collapse of root organelles is enhanced in the pnp mutant under P deprivation and occurred with low frequency under P-replete conditions. Global analyses of metabolites and transcripts were carried out to understand the molecular bases of these altered P deprivation responses. We found that the pnp mutant expresses some elements of the deprivation response even when grown on a full nutrient medium, including altered transcript accumulation, although its total and inorganic P contents are not reduced. The pnp mutation also confers P status-independent responses, including but not limited to stress responses. Taken together, our data support the hypothesis that the activity of the chloroplast PNPase is involved in plant acclimation to P availability and that it may help maintain an appropriate balance of P metabolites even under normal growth conditions.