Biology subjects

Philip, A.

Publications and source records attributed to Philip, A..

6 recordsLinked to original sources

bioRxiv2026

A CD109-SMURF2 Axis Diverts EGFR from Degradation to Sustain Oncogenic Signaling and Promote Squamous Cell Carcinoma Invasion and Stemness

Squamous cell carcinoma (SCC) remains difficult to treat, particularly in recurrent or metastatic disease. Although EGFR signaling is a well-established driver of SCC pathogenesis, mechanisms regulating its activity remain incompletely understood. CD109, a GPI-anchored glycoprotein frequently overexpressed in SCC, has been implicated in EGFR signaling, but its mechanisms remain poorly defined. Here, we show that CD109 is elevated in head and neck SCC (HNSCC) in the TCGA PanCancer Atlas and significantly correlates with reduced disease-free survival. Integrative transcriptomic (TCGA PanCancer Atlas) and proteomic (LinkedOmics) analyses revealed strong positive correlations between CD109, EGFR, and SMURF2. These findings were further validated by immunohistochemistry in HNSCC patient samples. Mechanistically, CD109 overexpression impaired EGFR degradation, suppressed degradation-associated EGFR pY1045 phosphorylation, and enhanced signaling-associated pY1068 phosphorylation, resulting in increased STAT3, AKT, and ERK signaling. We identify SMURF2 as a mediator of these effects, with CD109 promoting EGFR-SMURF2 complex formation. SMURF2 gain- and loss-of-function studies in SCC cells, demonstrated that SMURF2 stabilizes EGFR by reducing EGFR interaction with the ubiquitin ligase c-Cbl, thereby limiting EGFR turnover in a CD109-dependent manner. Functionally, the CD109-SMURF2-EGFR axis promotes EGF-induced stemness, invasion, and proliferation in SCC cells. Together, these findings identify CD109 as a molecular switch controlling EGFR fate by redirecting EGFR from c-Cbl-mediated degradation toward SMURF2-dependent stabilization, sustaining oncogenic signaling. This previously unrecognized regulatory pathway reveals the CD109-SMURF2 axis as a vulnerability with potential for targeted intervention in EGFR-driven SCCs.

cancer biology↗

bioRxiv2026

Loss of CD109 Amplifies NF-κB Signaling and Inflammatory Reprogramming in Dermal Fibroblasts

Fibroproliferative diseases such as systemic sclerosis are complex conditions characterized by chronic skin inflammation and progressive fibrosis, with fibroblast activation as a central feature. While Transforming Growth Factor Beta (TGF-{beta}) signaling is a well-established driver of fibrosis in SSc, inflammatory pathways such as Nuclear Factor Kappa B (NF-{kappa}B) also contribute substantially to disease morbidity. We previously identified CD109 as a TGF-{beta} co-receptor and negative regulator of fibrotic signaling; however, its role in inflammatory signaling remains unknown. Here, we investigate the function of CD109 in regulating inflammatory signaling in skin fibroblasts. We show that, CD109 co-localizes and associates with Toll-like receptors (TLR2, TLR4) and tumor necrosis factor receptors (TNFRI, TNFRII), and that loss of CD109 enhances TNF--induced NF-{kappa}B activation and reprograms cytokine production in human dermal fibroblasts. Furthermore, both global and fibroblast-specific CD109 knockout mice exhibit increased immune cell infiltration and skin inflammation. In parallel, single-cell transcriptomic analyses across a pan-disease fibroblast atlas show that CD109 expression is preferentially maintained in structural and homeostatic fibroblast subtypes, whereas immune-interacting fibroblast subsets consistently display decreased CD109 levels. Pathway-level analyses of fibroblast pseudobulk samples reveal altered activity of canonical inflammatory pathways in SSc compared to healthy skin. Together, these findings identify CD109 as a fibroblast-intrinsic negative regulator of inflammatory signaling and suggest a broader role for CD109 in modulating inflammatory responses in systemic sclerosis. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=102 SRC="FIGDIR/small/736423v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@ba5107org.highwire.dtl.DTLVardef@1de28aorg.highwire.dtl.DTLVardef@3e8a6org.highwire.dtl.DTLVardef@9f1a82_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract: CD109 Restrains Fibroblast-Driven Inflammation by Modulating NF-{kappa}B Signaling. Generated using FigureLabs.ai and edited using Adobe Photoshop. C_FIG

cell biology↗

bioRxiv2026

Rewiring of EGFR oncogenic program by opposing actions of membrane versus soluble CD109 in HNSCC

The epidermal growth factor receptor (EGFR) expression is often dysregulated in head and neck squamous cell carcinoma (HNSCC), driving cancer cell proliferation, invasion, and metastasis through diverse pathways, thereby contributing to aggressive chemo- and radio-therapy resistance. A GPI-anchored protein, CD109 is upregulated in multiple cancers, including HNSCC. While membrane-anchored CD109 (mCD109) is pro-tumorigenic in SCC via EGFR/STAT3 activation, the role of protease-cleaved soluble CD109 (sCD109) is poorly understood. Our groundbreaking findings demonstrate that sCD109 antagonizes EGFR signaling by directly binding to the EGFR extracellular domain, preventing mCD109-EGFR stabilizing interactions on the cell surface, followed by inhibition of EGFR phosphorylation at Y1068 and downstream signaling cascades (AKT, MAPK, and STAT3) consequently suppressing cancer cell migration, invasion, 3D tumor spheroid formation and angiogenic tube formation. In addition, we found that sCD109 regulates EGFR fates by inhibiting nuclear localization of phosphorylated EGFR and promoting EGFR degradation. Additionally, sCD109 significantly reduces EGF-induced expression of cancer stem cell markers (CD44 and CD133) and embryonic stem cell markers (Nanog and Sox2), suggesting a suppressive role in cancer stemness. Taken together, these results underscore the opposing roles of mCD109 and sCD109: with sCD109 acting as an antagonist by inhibiting mCD109/EGFR-driven oncogenic signaling and phenotypes. Our current findings reveal a complex interplay among mCD109, sCD109, and EGFR, identifying a mechanism for targeting EGFRs degradation in HNSCC, and lay the groundwork for future research on investigating sCD109s modulatory role in preclinical models of HNSCC.

Cancer Biology↗

bioRxiv2026

Epidermal CD109 Overexpression Limits Cutaneous Inflammatory Signaling

Psoriasis is a chronic immune-mediated inflammatory skin disease characterized by excessive keratinocyte proliferation, immune cell infiltration and dysregulated inflammatory signaling. Despite the availability of biologic therapies targeting inflammatory cytokines, many patients experience incomplete responses or relapse, highlighting the need to better understand molecular regulators of cutaneous inflammation. CD109 is a glycosylphosphatidylinositol (GPI)-anchored protein previously identified by our lab as a co-receptor and negative regulator of Transforming Growth Factor-{beta} (TGF-{beta}) signaling that inhibits fibrotic responses. Emerging evidence suggests that CD109 also modulates immune and inflammatory pathways. In this study, we investigated whether epidermal CD109 overexpression influences cutaneous inflammatory responses. Transgenic (TG) mice overexpressing CD109 under the keratin-14 (K14) promoter were used to restrict transgene expression to the epidermis. TG and wild-type (WT) littermates were subjected to lipopolysaccharide (LPS)-induced skin inflammation. CD109 TG mice exhibited significantly reduced immune cell recruitment, including macrophages and neutrophils, along with decreased expression of the pro-inflammatory mediators IL-1 and MCP-1/CCL2 compared with WT mice. Transcriptomic analysis of primary keratinocytes revealed downregulation of multiple inflammatory signaling pathways in CD109-overexpressing cells, including TNF-/NF-{kappa}B, IL-2/STAT5, IFN-{gamma}, IFN-, and IL-6/JAK/STAT3 pathways. Together, these findings demonstrate that epidermal CD109 overexpression attenuates cutaneous inflammatory responses by suppressing key inflammatory signaling networks and limiting immune cell recruitment, suggesting that CD109 may represent an important regulator of inflammatory signaling in the skin and a potential target for inflammatory skin diseases such as psoriasis.

immunology↗

bioRxiv2021

Mitochondrial OPA1 deficiency causes reversible defects in adult neurogenesis-associated spatial memory in mice

Mitochondria are integrative hubs central to cellular adaptive pathways. Such pathways are critical in highly differentiated post-mitotic neurons, the plasticity of which sustains brain function. Consequently, defects in mitochondrial dynamics and quality control appear instrumental in neurodegenerative diseases and may also participate in cognitive impairments. To directly test this hypothesis, we analyzed cognitive performances in a mouse mitochondria-based disease model, due to haploinsufficiency in the mitochondrial optic-atrophy-type-1 (OPA1) protein. While in Dominant Optic Atrophy (DOA) models, the known main symptoms are late onset visual deficits, we discovered early impairments in hippocampus-dependent spatial memory attributable to defects in adult neurogenesis. Moreover, less connected hippocampal adult-born neurons showed a decrease in mitochondrial content. Remarkably, modulating mitochondrial function through voluntary exercise or pharmacological treatment restored spatial memory. Altogether, our study identifies a crucial role for OPA1-dependent mitochondrial functions in adult neurogenesis, and thus in hippocampal-dependent cognitive functions. More generally, our findings show that adult neurogenesis is highly sensitive to mild mitochondrial defects, generating impairments in spatial memory that can be detected at an early stage and counterbalanced by physical exercise and pharmacological targeting of mitochondrial dynamics. Thus, early amplification of mitochondrial function appears beneficial for late-onset neurodegenerative diseases.

neuroscience↗

bioRxiv2019

Generation of Recombinant Rotavirus Expressing NSP3-UnaG Fusion Protein by a Simplified Reverse Genetics System

Rotavirus is a segmented double-stranded (ds)RNA virus that causes severe gastroenteritis in young children. We have established an efficient simplified rotavirus reverse genetics (RG) system that uses eleven T7 plasmids, each expressing a unique simian SA11 (+)RNA, and a CMV support plasmid for the African swine fever virus NP868R capping enzyme. With the NP868R-based system, we generated recombinant rotavirus (rSA11/NSP3-FL-UnaG) with a genetically modified 1.5-kB segment 7 dsRNA that encodes full-length NSP3 fused to UnaG, a 139-aa green fluorescent protein (FP). Analysis of rSA11/NSP3-FL-UnaG showed that the virus replicated efficiently and was genetically stable over 10 rounds of serial passage. The NSP3-UnaG fusion product was well expressed in rSA11/NSP3-FL-UnaG-infected cells, reaching levels similar to NSP3 in wildtype rSA11-infected cells. Moreover, the NSP3-UnaG protein, like functional wildtype NSP3, formed dimers in vivo. Notably, NSP3-UnaG protein was readily detected in infected cells via live cell imaging, with intensity levels ~3-fold greater than that of the NSP1-UnaG fusion product of rSA11/NSP1-FL-UnaG. Our results indicate that FP-expressing recombinant rotaviruses can be made through manipulation of the segment 7 dsRNA without deleting or interrupting any of the twelve open reading frames of the virus. Because NSP3 is expressed at levels higher than NSP1 in infected cells, rotaviruses expressing NSP3-based FPs may be a more sensitive tool for studying rotavirus biology than rotaviruses expressing NSP1-based FPs. This is the first report of a recombinant rotavirus containing a genetically engineered segment 7 dsRNA.\n\nImportancePrevious studies have generated recombinant rotaviruses that express fluorescent proteins (FPs) by inserting reporter genes into the NSP1 open reading frame (ORF) of genome segment 5. Unfortunately, NSP1 is expressed at low levels in infected cells, making viruses expressing FP-fused NSP1 less than ideal probes of rotavirus biology. Moreover, FPs were inserted into segment 5 in such a way as to compromise NSP1, an interferon antagonist affecting viral growth and pathogenesis. We have identified an alternative approach for generating rotaviruses expressing FPs, one relying on fusing the reporter gene to the NSP3 ORF of genome segment 7. This was accomplished without interrupting any of the viral ORFs, yielding recombinant viruses likely expressing the complete set of functional viral proteins. Given that NSP3 is made at moderate levels in infected cells, rotavirus encoding NSP3-based FPs should be more sensitive probes of viral infection than rotaviruses encoding NSP1-based FPs.

microbiology↗