bioRxiv Science⌕ Search

Biology subjects

Lou, P.

Publications and source records attributed to Lou, P..

6 recordsLinked to original sources

A human-in-the-loop explanation framework for morphologically transparent AI predictions from whole-slide images

Deep learning models enable the prediction of clinical endpoints from whole-slide images (WSIs), but many such models function as "black boxes", lacking transparency about whether and which histomorphological patterns drive their predictions, hindering interpretability and clinical adoption. Here we propose a human-in-the-loop explanation framework, MorphoXAI, which provides both local and global interpretability for deep learning models by incorporating human-expert interpretations. At the global level, it reveals the histomorphological patterns on which the model consistently relies to distinguish between classes of WSIs, as well as the patterns associated with confusion between classes. At the local level, it indicates which of these patterns are used in the prediction of an individual WSI and which regions within the slide correspond to such patterns. We validated our method on a deep learning model trained for ovarian tumor histologic subtype prediction. The results show that our framework generates explanations that accurately reflect the histomorphology underlying the models predictions at both global and local levels. For interpretability and clinical utility in diagnostic contexts, human evaluation results showed that our explanations were easy to interpret, rich in diagnostic features, and directly helpful for diagnostic decision-making, thereby enhancing pathologist-AI collaboration. Our work highlights that unifying global and local explanations and grounding them in expert-interpreted morphology enhances the interpretability and verifiability of deep learning models, thereby facilitating the transparent deployment of such models in clinical practice.

pathology↗

Unveiling the functional heterogeneity of endogenous tissue extracellular vesicles in skeletal muscle through multi-omics

Extracellular vesicles (EVs) have emerged as promising tools for the development of disease biomarkers and therapeutics because they can transfer various bioactive cargos between cells in vivo. A better understanding of the heterogeneous properties of EVs in vivo may provide insights into their biological roles and clinical translation potential. As a proof-of-concept, we report that different EV subpopulations from skeletal muscle tissues have distinct composition signatures and diverse biological effects on recipient cells. Multiple cell types (e.g., myoblasts and endothelial cells (ECs)) can contribute to the pool of muscle tissue-derived EVs, and large EVs (L-EVs) are enriched with proteins related to metabolic regulation, whereas small EVs (S-EVs) are enriched with original muscle cell-specific proteins related to muscle function regulation. Compared with L-EVs, S-EVs exhibited abundant surface proteins and higher cell uptake rates. Moreover, L-EVs and S-EVs can induce diverse changes in global gene expression, metabolic patterns and some cellular behaviors (e.g., proliferation and differentiation) in recipient cells. These results suggest that different EV subpopulations might control tissue hemostasis in a coordinated manner and suggest the importance of reconsidering their favorable role in future applications (e.g., S-EVs for biomarker discovery and L-EVs for metabolic intervention). This study highlights the functional heterogeneity of tissue-derived EVs in vivo, and the selection of an ideal EV subset on the basis of its specific biological properties may be a promising strategy for developing more precise biomarkers or tailored EV therapies for regenerative medicine. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=60 SRC="FIGDIR/small/624461v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@6a9a0forg.highwire.dtl.DTLVardef@a86cbforg.highwire.dtl.DTLVardef@17b8680org.highwire.dtl.DTLVardef@bb718d_HPS_FORMAT_FIGEXP M_FIG C_FIG SignificanceExtracellular vesicles (EVs) are emerging as important tools for diagnostics, therapeutics, and prognostics in various diseases. Understanding the inherent heterogeneity of EVs is crucial, as distinct subpopulations function differently. While extensive research focuses on EVs derived from cell supernatants, endogenous tissue EVs can more accurately reflect the pathophysiological characteristics of their originating cells. Here, we propose different tissue-EV subpopulations coordinately regulate tissue homeostasis. Small EVs with tissue-specific signatures show promise for biomarker development, while large EVs with metabolic signatures are suitable for metabolic interventions. Additionally, small EVs with enhanced surface proteins are ideal for targeted delivery. This work highlights the importance of selecting tissue-EV subpopulations based on their unique properties for developing precise biomarkers and tailored therapies in regenerative medicine.

cell biology↗

Peritoneal M2 macrophage-derived extracellular vesicles as natural multi-target nanotherapeutics to attenuate cytokine storm after severe infections

Cytokine storm is a primary cause for multiple organ damage and death after severe infections, such as SARS-CoV-2. However, current single cytokine-targeted strategies display limited therapeutic efficacy. Here, we report that peritoneal M2 macrophages-derived extracellular vesicles (M2-EVs) are multi-target nanotherapeutics to resolve cytokine storm. In detail, primary peritoneal M2 macrophages exhibited superior anti-inflammatory potential than immobilized cell lines. Systemically administrated M2-EVs entered major organs and were taken up by phagocytes (e.g., macrophages). M2-EVs treatment effectively reduced excessive cytokine (e.g., TNF- and IL-6) release in vitro and in vivo, thereby attenuated oxidative stress and multiple organ (lung, liver, spleen and kidney) damage in endotoxin-induced cytokine storm. Moreover, M2-EVs simultaneously inhibited multiple key proinflammatory pathways (e.g., NF-{kappa}B, JAK-STAT and p38 MAPK) by regulating complex miRNA-gene and gene-gene networks, and this effect was collectively mediated by many functional cargos (miRNAs and proteins) in EVs. In addition to the direct anti-inflammatory role, human peritoneal M2-EVs expressed angiotensin-converting enzyme 2 (ACE2), a receptor of SARS-CoV-2 spike protein, and thus could serve as nanodecoys to prevent SARS-CoV-2 pseudovirus infection in vitro. As cell-derived nanomaterials, the therapeutic index of M2-EVs can be further improved by genetic/chemical modification or loading with specific drugs. This study highlights that peritoneal M2-EVs are promising multifunctional nanotherapeutics to attenuate infectious diseases-related cytokine storm.

immunology↗

Genetic and Genomic Resources to Study Natural Variation in Brassica rapa

ABSTRACTThe globally important crop Brassica rapa, a close relative of Arabidopsis, is an excellent system for modeling our current knowledge of plant growth on a morphologically diverse crop. The long history of B. rapa domestication across Asia and Europe provides a unique collection of locally adapted varieties that span large climatic regions with various abiotic and biotic stress tolerance traits. This diverse gene pool provides a rich source of targets with the potential for manipulation towards the enhancement of productivity of crops both within and outside the Brassicaceae. To expand the genetic resources available to study natural variation in B. rapa, we constructed an Advanced Intercross Recombinant Inbred (AI-RIL) population using B. rapa subsp. trilocularis (Yellow Sarson) R500 and the B. rapa subsp. parachinensis (Cai Xin) variety L58. Our current understanding of genomic structure variation across crops suggests that a single reference genome is insufficient for capturing the genetic diversity within a species. To complement this AI-RIL population and current and future B. rapa genomic resources, we generated a de novo genome assembly of the B. rapa subsp. trilocularis (Yellow Sarson) variety R500, the maternal parent of the AI-RIL population. The genetic map for the R500 x L58 population generated using this de novo genome was used to map QTL for seed coat color and revealed the improved mapping resolution afforded by this new assembly.Competing Interest StatementThe authors have declared no competing interest.View Full Text

plant biology↗

Expansion of the circadian transcriptome in Brassica rapa and genome-wide diversification of paralog expression patterns

An important challenge of crop improvement strategies is assigning function to paralogs in polyploid crops. Gene expression is one method for determining the activity of paralogs; however, the majority of transcript abundance data represents a static point that does not consider the spatial and temporal dynamics of the transcriptome. Studies in Arabidopsis have estimated up to 90% of the transcriptome to be under diel or circadian control depending on the condition. As a result, time of day effects on the transcriptome have major implications on how we characterize gene activity. In this study, we aimed to resolve the circadian transcriptome in the polyploid crop Brassica rapa and explore the fate of multicopy orthologs of Arabidopsis circadian regulated genes. We performed a high-resolution time course study with 2 h sampling density to capture the genes under circadian control. Strikingly, more than two-thirds of expressed genes exhibited rhythmicity indicative of circadian regulation. To compare the expression patterns of paralogous genes, we developed a program in R called DiPALM (Differential Pattern Analysis by Linear Models) that analyzes time course data to identify transcripts with significant pattern differences. Using DiPALM, we identified genome-wide divergence of expression patterns among retained paralogs. Cross-comparison with a previously generated diel drought experiment in B. rapa revealed evidence for differential drought response for these diverging paralog pairs. Using gene regulatory network models we compared transcription factor targets between B. rapa and Arabidopsis circadian networks to reveal additional evidence for divergence in expression between B. rapa paralogs that may be driven in part by variation in conserved non coding sequences. These findings provide new insight into the rapid expansion and divergence of the transcriptional network in a polyploid crop and offer a new method for assessing paralog activity at the transcript level. SignificanceThe circadian regulation of the transcriptome leads to time of day changes in gene expression that coordinates environmental conditions with physiological responses. Brassica rapa, a morphologically diverse crop species, has undergone whole genome triplication since diverging from Arabidopsis resulting in an expansion of gene copy number. To examine how this expansion has influenced the circadian transcriptome we developed a new method for comparing gene expression patterns. This method facilitated the discovery of genome-wide expansion of expression patterns for genes present in multiple copies and divergence in temporal abiotic stress response. We find support for conserved sequences outside the gene body contributing to these expression pattern differences and ultimately generating new connections in the gene regulatory network.

genomics↗

Stromal ISLR promotes intestinal regeneration and cancer by suppressing epithelial Hippo signaling

The YAP signaling activation in epithelial cells is essential for intestinal regeneration and tumorigenesis. However, the molecular mechanism linking stromal signals to YAP-mediated intestinal regeneration and tumorigenesis is poorly defined. Here we report a stroma-epithelia YAP signaling axis essential for stromal cells to modulate epithelial cell growth during intestinal regeneration and tumorigenesis. Specifically, upon inflammation and in cancer, an oncogenic transcription factor ETS1 in stromal cells induces expression of a secreted protein ISLR that can directly binds to a transmembrane protocadherin FAT1 on the surface of epithelial cells. This binding suppressed the Hippo signaling by disrupting MST1-FAT1 association, resulting in YAP signaling activation. Deletion of Islr in stromal cells in mice markedly impaired intestinal regeneration, and suppressed tumorigenesis in the colon. Moreover, the expression of stromal cell-specific ISLR and ETS1 significantly increased in inflamed mucosa of human IBD patients and in human colorectal adenocarcinoma, accounting for the epithelial YAP hyperactivation. Collectively, our findings uncovered a molecular mechanism governing signals for communication between stroma and epithelium during tissue regeneration and tumorigenesis.

cancer biology↗