Intrinsic and Extrinsic Contributors to the Cardiac Benefits of Exercise.

Among its many cardiovascular benefits, exercise training improves heart function and protects the heart against age-related decline, pathological stress, and injury. Here, we focus on cardiac benefits with an emphasis on more recent updates to our understanding. While the cardiomyocyte continues to play a central role as both a target and effector of exercise's benefits, there is a growing recognition of the important roles of other, noncardiomyocyte lineages and pathways, including some that lie outside the heart itself. We review what is known about mediators of exercise's benefits-both those intrinsic to the heart (at the level of cardiomyocytes, fibroblasts, or vascular cells) and those that are systemic (including metabolism, inflammation, the microbiome, and aging)-highlighting what is known about the molecular mechanisms responsible.

Treatment of calcific arterial disease via enhancement of autophagy using GSK343.

Vascular calcification is a hallmark of atherosclerotic disease and serves as a strong predictor and risk factor for cardiovascular events. Growing evidence suggests that autophagy may play a protective role in early atherosclerosis. The precise effects of autophagy on VSMC-mediated calcification remain unknown. In this study, we utilized multi-omic profiling to investigate impaired autophagy at the transcriptional level as a key driver of VSMC calcification. Our findings revealed that impaired autophagy is an essential determinant of VSMC calcification. We observed that an osteogenic environment affects the open chromatin status of VSMCs, compromising the transcriptional activation of autophagy initiation genes. In vivo experiments involve pharmacological and genetic activation of autophagy using mouse models of spontaneous large (Mgp-/-) and small (Abcc6-/-) artery calcification. Taken together, these data advance our mechanistic understanding of vascular calcification and provide important insights for a broad range of cardiovascular diseases involving VSMC phenotype switch.

Lymphatic muscle cells are unique cells that undergo aging induced changes.

Lymphatic muscle cells (LMCs) within the wall of collecting lymphatic vessels exhibit tonic and autonomous phasic contractions, which drive active lymph transport to maintain tissue-fluid homeostasis and support immune surveillance. Damage to LMCs disrupts lymphatic function and is related to various diseases. Despite their importance, knowledge of the transcriptional signatures in LMCs and how they relate to lymphatic function in normal and disease contexts is largely missing. We have generated a comprehensive transcriptional single-cell atlas-including LMCs-of collecting lymphatic vessels in mouse dermis at various ages. We identified genes that distinguish LMCs from other types of muscle cells, characterized the phenotypical and transcriptomic changes in LMCs in aged vessels, and uncovered a pro-inflammatory microenvironment that suppresses the contractile apparatus in advanced-aged LMCs. Our findings provide a valuable resource to accelerate future research for the identification of potential drug targets on LMCs to preserve lymphatic vessel function as well as supporting studies to identify genetic causes of primary lymphedema currently with unknown molecular explanation.

Beyond cardiomyocytes: Cellular diversity in the heart's response to exercise.

Cardiomyocytes comprise ∼70% to 85% of the total volume of the adult mammalian heart but only about 25% to 35% of its total number of cells. Advances in single cell and single nuclei RNA sequencing have greatly facilitated investigation into and increased appreciation of the potential functions of non-cardiomyocytes in the heart. While much of this work has focused on the relationship between non-cardiomyocytes, disease, and the heart's response to pathological stress, it will also be important to understand the roles that these cells play in the healthy heart, cardiac homeostasis, and the response to physiological stress such as exercise. The present review summarizes recent research highlighting dynamic changes in non-cardiomyocytes in response to the physiological stress of exercise. Of particular interest are changes in fibrotic pathways, the cardiac vasculature, and immune or inflammatory cells. In many instances, limited data are available about how specific lineages change in response to exercise or whether the changes observed are functionally important, underscoring the need for further research.

Acquired lymphedema: Molecular contributors and future directions for developing intervention strategies.

Lymphedema is a debilitating chronic disease that mostly develops as an adverse reaction to cancer treatment modalities such as chemotherapy, surgery, and radiotherapy. Lymphedema also appears to be a deteriorating consequence of roundworm infections, as best represented by filariasis. According to its origin, lymphedema is classified as primary lymphedema and acquired lymphedema. The latter is an acquired condition that, hitherto, received a considerably low attention owing to the less number of fatal cases been reported. Notably, despite the low mortality rate in lymphedema, it has been widely reported to reduce the disease-free survival and thus the quality of life of affected patients. Hence, in this review, we focused on acquired lymphedema and orchestration of molecular interplays associated with either stimulation or inhibition of lymphedema development that were, in vast majority, clearly depicted in animal models with their specific and distinct technical approaches. We also discussed some recent progress made in phytochemical-based anti-lymphedema intervention strategies and the specific mechanisms underlying their anti-lymphedema properties. This review is crucial to understand not only the comprehensive aspects of the disease but also the future directions of the intervention strategies that can address the quality of life of affected patients rather than alleviating apparent symptoms only.

A particulate saponin/TLR agonist vaccine adjuvant alters lymph flow and modulates adaptive immunity.

Saponins are potent and safe vaccine adjuvants, but their mechanisms of action remain incompletely understood. Here, we explored the properties of several saponin formulations, including immune-stimulatory complexes (ISCOMs) formed by the self-assembly of saponin and phospholipids in the absence or presence of the Toll-like receptor 4 agonist monophosphoryl lipid A (MPLA). We found that MPLA self-assembles with saponins to form particles physically resembling ISCOMs, which we termed saponin/MPLA nanoparticles (SMNP). Saponin-containing adjuvants exhibited distinctive mechanisms of action, altering lymph flow in a mast cell­dependent manner and promoting antigen entry into draining lymph nodes. SMNP was particularly effective, exhibiting even greater potency than the compositionally related adjuvant AS01B in mice, and primed robust germinal center B cell, TFH, and HIV tier 2 neutralizing antibodies in nonhuman primates. Together, these findings shed new light on mechanisms by which saponin adjuvants act to promote the immune response and suggest that SMNP may be a promising adjuvant in the setting of HIV, SARS-CoV-2, and other pathogens.

Exercise Training Improves Tumor Control by Increasing CD8+ T-cell Infiltration via CXCR3 Signaling and Sensitizes Breast Cancer to Immune Checkpoint Blockade.

The mechanisms behind the antitumor effects of exercise training (ExTr) are not fully understood. Using mouse models of established breast cancer, we examined here the causal role of CD8+ T cells in the benefit acquired from ExTr in tumor control, as well as the ability of ExTr to improve immunotherapy responses. We implanted E0771, EMT6, MMTV-PyMT, and MCa-M3C breast cancer cells orthotopically in wild-type or Cxcr3-/- female mice and initiated intensity-controlled ExTr sessions when tumors reached approximately 100 mm3 We characterized the tumor microenvironment (TME) using flow cytometry, transcriptome analysis, proteome array, ELISA, and immunohistochemistry. We used antibodies against CD8+ T cells for cell depletion. Treatment with immune checkpoint blockade (ICB) consisted of anti-PD-1 alone or in combination with anti-CTLA-4. ExTr delayed tumor growth and induced vessel normalization, demonstrated by increased pericyte coverage and perfusion and by decreased hypoxia. ExTr boosted CD8+ T-cell infiltration, with enhanced effector function. CD8+ T-cell depletion prevented the antitumor effect of ExTr. The recruitment of CD8+ T cells and the antitumor effects of ExTr were abrogated in Cxcr3-/- mice, supporting the causal role of the CXCL9/CXCL11-CXCR3 pathway. ExTr also sensitized ICB-refractory breast cancers to treatment. Our results indicate that ExTr can normalize the tumor vasculature, reprogram the immune TME, and enhance the antitumor activity mediated by CD8+ T cells via CXCR3, boosting ICB responses. Our findings and mechanistic insights provide a rationale for the clinical translation of ExTr to improve immunotherapy of breast cancer.

Characteristics of Lymphedema in Patients Treated with Mammalian Target of Rapamycin Inhibitors.

Purpose: To investigate the characteristics of lymphedema in patients treated with mammalian target of rapamycin (mTOR) inhibitors and delineate complex decongestive therapy (CDT) outcomes. Methods and Results: We retrospectively analyzed 24 patients with mTOR inhibitor-induced lymphedema and 7 lymphedema patients (control) not treated with mTOR inhibitors, who visited the lymphedema clinic of the department of rehabilitation medicine from March 2016 to December 2019. We comprehensively reviewed clinical features, medication history, associated diseases, lymphoscintigraphy, lower extremity computed tomography venography (LE CTV), and the effect of CDT. By using ImageJ program, we measured the cross-sectional area (CSA) of muscle and subcutaneous fat of mid-thigh image in LE CTV and compared them to a control group not treated with mTOR inhibitors. Seventeen patients on sirolimus and seven patients on everolimus were included, with an approximately equal distribution of stages 2 and 3 lymphedema, and most with pitting edema. Ten patients had breast or gynecological cancer and underwent lymph node dissection. Lymphedema developed after mTOR inhibitor initiation, not postoperatively. Lymphoscintigraphy revealed decreased lymph node uptake and dermal backflow. LE CTV revealed subcutaneous honeycomb-shaped trabecular areas in the affected limbs of seven patients. Patients treated with mTOR inhibitors had a larger mean subcutaneous fat CSA and a smaller mean muscular CSA than controls. Lymphedema improved or remained unchanged after initial CDT. Daily CDT adequately controlled 11 cases, but exacerbation occurred in 5 of 7 poorly compliant patients, and cellulitis occurred in 6 patients. Conclusion: Physicians should identify mTOR inhibitor-related lymphedema early and discuss medication alternatives and CDT with patients.

Synthesis and evaluation of butein derivatives for in vitro and in vivo inflammatory response suppression in lymphedema.

Herein, we demonstrate that butein (1) can prevent swelling in a murine lymphedema model by suppressing tumor necrosis factor α (TNF-α) production. Butein derivatives were synthesized and evaluated to identify compounds with in vitro anti-inflammatory activity. Among them, 20 µM of compounds 7j, 7m, and 14a showed 50% suppression of TNF-α production in mouse peritoneal macrophages after lipopolysaccharide stimulation. Compound 14a, exhibited the strongest potency with an in vitro IC50 of 14.6 µM and suppressed limb volume by 70% in a murine lymphedema model. The prodrug strategy enabled a six-fold increase in kinetic solubility of compound 1 and five-fold higher levels of active metabolite in the blood for compound 14a via oral administration in the pharmacokinetics study. We suggest that the compound 14a could be developed as a potential therapeutic agent targeting anti-inflammatory activity to alleviate lymphedema progression.

Hormetic dose response to L-ascorbic acid as an anti-cancer drug in colorectal cancer cell lines according to SVCT-2 expression.

L-Ascorbic acid (vitamin C, AA) exhibits anti-cancer effects with high-dose treatment through the generation of reactive oxygen species (ROS) and selective damage to cancer cells. The anti-cancer effects of L-ascorbic acid are determined by sodium-dependent vitamin C transporter 2 (SVCT-2), a transporter of L-ascorbic acid. In this study, we demonstrate that L-ascorbic acid treatment showed efficient anti-cancer activity in cell lines with high expression levels of SVCT-2 for a gradient concentration of L-ascorbic acid from 10 µM -2 mM. However, in low SVCT-2 expressing cell lines, high-dose L-ascorbic acid (>1 mM) showed anti-cancer effects but low-dose (<10 µM) treatment induced cell proliferation. Such conflicting results that depend on the concentration are called a hormetic dose response. A hormetic dose response to low-dose L-ascorbic acid was also observed in high SVCT-2 expressing cell lines in the presence of a SVCT family inhibitor. Insufficient uptake of L-ascorbic acid in low SVCT-2 expressing cancer cell lines cannot generate sufficient ROS to kill cancer cells, resulting in the hormetic response. Molecular analysis confirmed the increased expression of cancer proliferation markers in the hormetic dose response. These results suggest that L-ascorbic exhibits a biphasic effect in cancer cells depending on SVCT-2 expression.

Sulfuretin has therapeutic activity against acquired lymphedema by reducing adipogenesis.

Acquired lymphedema is a pathological condition associated with lymphatic dysfunction caused by surgical treatments for cancer. Although global estimates of the prevalence of acquired lymphedema have been rising, there are currently no effective therapeutics available. Since adipose tissue accumulation is a clinical hallmark of lymphedema, we hypothesized that regulation of adipogenesis in lymphedematous tissue could be used as a therapeutic intervention against lymphedema. Toward this, we investigated the possibility of anti-adipogenic 30% ethanol Rhus verniciflua Stokes (RVS) extract as a potential lymphedema treatment. Oral administration of RVS extract ameliorated volumetric symptoms of lymphedema in a mouse model. RVS administration also reduced adipose tissue accumulation in lymphedematous tissue and downregulated expression of adipocyte markers, including Pparγ and Fabp4. Sulfuretin was identified as a major bioactive compound in the 30% ethanol RVS extract in liquid chromatography-mass spectrometry analysis. Similar to the activities of RVS, sulfuretin inhibited adipocyte differentiation in 3T3-L1 preadipocytes. Moreover, treatment with sulfuretin on lymphedema-induced mice reduced lymphedema volume, decreased the expression of adipogenic markers, but induced the expression of markers associated with lymphangiogenesis. Taken together, our data raise the possibility that sulfuretin might be used in therapeutic interventions against acquired lymphedema.

Glutathione alleviated peripheral neuropathy in oxaliplatin-treated mice by removing aluminum from dorsal root ganglia.

Oxaliplatin, a platinum-based anti-cancer drug, induces peripheral neuropathy as a side effect and causes cold hyperalgesia in cancer patients receiving anti-cancer chemotherapy. In oxaliplatin-treated mice, aluminum was accumulated in the dorsal root ganglia (DRG), and accumulated aluminum in DRG or other organs aggravated oxaliplatin-induced neuropathic pain. To investigate whether aluminum oxalate, which is the compound of aluminum and oxaliplatin, might be the peripheral neuropathy inducer, the withdrawal responses of mice to coldness, the expression of transient receptor potential ankyrin 1 and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays in DRG were analyzed in mice administered with aluminum oxalate. In addition, the concentrations of aluminum in aluminum oxalate-treated mice were significantly increased compared to those of mice treated with aluminum chloride. To alleviate neuropathic pain, glutathione (GSH), known as an antioxidant and a metal chelator, was injected into oxaliplatin-treated mice. The concentrations of aluminum in the DRG were decreased by the chelation action of GSH. Taken together, behavioral and molecular analyses also supported that aluminum accumulation on the DRG might be a factor for neuropathic pain. This result also suggested that the aluminum chelation by GSH can provide an alleviatory remedy of neuropathic pain for cancer patients with oxaliplatin-induced neuropathic pain.

Hydrolysis of Hyaluronic Acid in Lymphedematous Tissue Alleviates Fibrogenesis via TH1 Cell-Mediated Cytokine Expression.

Although surgery and radiation are beneficial for treating cancer, they can also lead to malfunctions of the lymphatic system such as secondary lymphedema. This abnormality of the lymphatic system is characterized by severe swelling, adipogenesis, inflammation, and fibrosis in the lymphedematous region. Moreover, the proliferation of fibrotic tissue in the lymphedematous region generates edema that is no longer spontaneously reversible. No treatment for fibrosis has been validated in patients with lymphedema. In our efforts to develop a therapeutic agent for lymphedema fibrosis, we used a newly established mouse hind limb model. Previous studies have demonstrated that hyaluronic acid accumulates in the lymphedematous region. Thus, we challenged mice with of hyaluronidase (HYAL), with the aim of reducing fibrogenesis. After subcutaneous injections in the lymphedematous mouse leg every two days, the volume of lymphedema had reduced significantly by 7 days post-operation. Histochemical analysis indicated that collagen accumulation and myofibroblast differentiation were decreased in epidermal tissues after HYAL injection. Moreover, it was associated with upregulation of interferon-gamma, increased numbers of Th1 cells, and downregulation of interleukin-4 and interleukin-6 in the lymphedematous region and spleen. These results indicate that hydrolysis of hyaluronic acid can boost an anti-fibrotic immune response in the mouse lymphedema model.

Therapeutic effects of hyaluronidase on acquired lymphedema using a newly developed mouse limb model.

Acquired lymphedema is one of the most dreaded side effects of cancer treatment, such as surgical treatment or irradiation. However, due to the lack of appropriate animal models, there is no effective therapeutic method to cure acquired lymphedema. To develop a reproducible acquired lymphedema animal model, we devised a mouse hind limb model by removing a superficial inguinal lymph node, a popliteal lymph node, a deep inguinal lymph node, and the femoral lymphatic vessel. We measured the volume of lymphedematous leg and observed the change in level of hyaluronic acid (HA) and lymphangiogenic factors after injecting hyaluronidase. Our model showed the distinguishable swelling and the reliable symptoms compared to previously reported models. In the lymphedematous regions of our model, we confirmed that HA, a major component of extracellular matrix, accumulated to higher levels than in a normal mouse. This lymphedema volume was rapidly reduced by treating hyaluronidase. Following hyaluronidase injection, the lymphedematous region of our model resembled a normal hind limb. Our findings indicated that hyaluronidase promoted lymphangiogenesis on the lymphedematous limb. Based on hyaluronidase treatment in the lymphedematous region, this could potentially be a new therapeutic approach for acquired lymphedema mediated through the modification of the size of HA fragments. Impact statement In this manuscript, the essence of the work described in this manuscript involves the development of (1) a mouse limb model showing acquired lymphedema and (2) a potent therapeutic treatment using hyaluronidase to remedy acquired lymphedema in our model. In order to develop a reproducible acquired lymphedema animal model that reflects the most common symptoms experienced by lymphedema patients, we devised a mouse hind limb model by removing lymph nodes and lymphatics. Our model showed the distinguishable swelling and the reliable symptoms compared to previously reported models. In the lymphedematous regions of our model, we confirmed that hyaluronic acid (HA) accumulated to higher levels than in a normal mouse. This lymphedema volume was rapidly reduced by treating the lymphedematous leg with hyaluronidase, which also degraded high molecular weight HA to low molecular weight HA. Immunohistochemical analysis, quantitative real-time PCR analysis and lymphangioscintigraphy showed that hyaluronidase enhanced lymphangiogenesis in the lymphedematous limb.

Seven low-mass ions in pretreatment serum as potential predictive markers of the chemoradiotherapy response of rectal cancer.

Preoperative chemoradiotherapy (CRT) is generally performed for locally advanced rectal cancer (LARC, cStage 2 or 3) to improve local disease control and patient survival. The pathological tumor response to CRT is a surrogate marker that is associated with oncological outcome. Thus, markers that predict the response to CRT would be valuable for individualizing treatment for LARC patients. The current study used metabolomics-based approaches to identify molecular markers that predict the response to CRT. Seventy-six patients with LARC who received pelvic radiotherapy and concurrent chemotherapy using tegafur-uracil and leucovorin were enrolled. Radical surgery was performed 6-8 weeks after the completion of CRT. The postsurgical pathological CRT response was evaluated using the ypStage or tumor regression grade. Profiling patterns of low-mass ions (LMIs) in the pretreatment sera were obtained from all patients using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Our previously developed two-step algorithms, which showed a powerful diagnostic capability during colorectal cancer screening, were then used to screen for meaningful LMIs with discriminatory power. One combination consisting of seven LMIs was identified, whose discriminatory score separated a good CRT response (ypStage 0-1) from a poor CRT response (ypStage 3-4) successfully. However, each individual LMI alone showed insignificant discriminatory power. This finding suggests that analysis of the LMIs in pretreatment serum could serve as a predictive marker of the CRT response in patients with LARC.

Proteomic profiling of lymphedema development in mouse model.

The lymphatic vascular system plays an important role in tissue fluid homeostasis. Lymphedema is a chronic, progressive, and incurable condition that leads to lymphatic fluid retention; it may be primary (heritable) or secondary (acquired) in nature. Although there is a growing understanding of lymphedema, methods for the prevention and treatment of lymphedema are still limited. In this study, we investigated differential protein expressions in sham-operated and lymphedema-operated mice for 3 days, using two-dimensional gel electrophoresis (2-DE) and mass spectrometry analysis. Male improved methodology for culturing noninbred (ICR) mice developed lymphedema in the right hindlimb. Twenty functional proteins were found to be differentially expressed between lymphedema induced-right leg tissue and normal left leg tissue. Out of these proteins, the protein levels of apolipoprotein A-1 preprotein, alpha-actinin-3, mCG21744, parkinson disease, serum amyloid P-component precursor, annexin A8, mKIAA0098 protein, and fibrinogen beta chain precursor were differentially upregulated in the lymphedema mice compared with the sham-operated group. Western blotting analysis was used to validate the proteomics results. Our results showing differential up-regulation of serum amyloid P-component precursor, parkinson disease, and apolipoprotein A-1 preprotein in lymphedema model over sham-operated model suggest important insights into pathophysiological target for lymphedema. Copyright © 2016 John Wiley & Sons, Ltd.

Antitumor effects of calgranulin B internalized in human colon cancer cells.

Calgranulin B is a small, calcium-binding protein expressed in neutrophils that is secreted into the tumor microenvironment in cancer cases. We previously showed that calgranulin B levels are increased in the stools of colorectal cancer patients. In patient tumor tissues, calgranulin B protein levels correlated with the presence of stromal inflammatory cells surrounding tumor cells, and calgranulin B promoter methylation was observed in both paired human tissues and colon cancer cell lines. Cell lines did not express calgranulin B, but in vitro studies showed that colon cancer cells internalized extracellular calgranulin B, while other types of cancer cells did not. Calgranulin B internalization led to reduced cell proliferation and increased apoptotic cell death. AKT and ERK signals were also increased after calgranulin B treatment, as were p53, ß-catenin, E-cadherin and cleaved caspase-3 levels. Additionally, a human protein microarray identified aurora A kinase as a calgranulin B binding partner, and binding inhibited aurora A kinase activity in a dose-dependent manner. Our findings demonstrate the antitumor effects of calgranulin B in the inflammatory microenvironment and suggest that calgranulin B could be potentially efficacious in the treatment of colon cancer.

Oxaliplatin-Induced Peripheral Neuropathy via TRPA1 Stimulation in Mice Dorsal Root Ganglion Is Correlated with Aluminum Accumulation.

Oxaliplatin is a platinum-based anticancer drug used to treat metastatic colorectal, breast, and lung cancers. While oxaliplatin kills cancer cells effectively, it exhibits several side effects of varying severity. Neuropathic pain is commonly experienced during treatment with oxaliplatin. Patients describe symptoms of paresthesias or dysesthesias that are triggered by cold (acute neuropathy), or as abnormal sensory or motor function (chronic neuropathy). In particular, we found that aluminum levels were relatively high in some cancer patients suffering from neuropathic pain based on clinical observations. Based on these findings, we hypothesized that aluminum accumulation in the dorsal root ganglion (DRG) in the course of oxaliplatin treatment exacerbates neuropathic pain. In mice injected with oxaliplatin (three cycles of 3 mg/kg i.p. daily for 5 days, followed by 5 days of rest), we detected cold allodynia using the acetone test, but not heat hyperalgesia using a hot plate. However, co-treatment with aluminum chloride (AlCl3∙6H2O; 7 mg/kg i.p. for 14 days: equivalent 0.78 mg/kg of elemental Al) and oxaliplatin (1 cycle of 3 mg/kg i.p. daily for 5 days, followed by 5 days of rest) synergistically induced cold allodynia as well as increased TRPAl mRNA and protein expression. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis showed a significant increase in aluminum concentrations in the DRG of mice treated with aluminum chloride and oxaliplatin compared to aluminum chloride alone. Similarly, in a mouse induced-tumor model, aluminum concentrations were increased in DRG tissue and tumor cells after oxaliplatin treatment. Taken together, these findings suggest that aluminum accumulation in the DRG may exacerbate neuropathic pain in oxaliplatin-treated mice.

Tomato yellow leaf curl virus Can Overwinter in Stellaria aquatica, a Winter-Hardy TYLCV-Reservoir Weed.

Tomato yellow leaf curl virus (TYLCV), one of the most serious plant viruses in tropical and subtropical regions, is transmitted to host plants by the vector insect Bemisia tabaci. In order to control TYLCV, it is important to identify weed hosts for overwintering TYLCV. Stellaria aquatica, a winter-hardy weed, was found growing with TYLCV-infected tomato plants in greenhouse production. TYLCV was detected in S. aquatica plants by polymerase chain reaction and Southern blot hybridization analysis. The intergenic region nucleotide sequences amplified from TYLCV-infected tomato plants, TYLCV-viruliferous whiteflies, and S. aquatica were identical. During winter (December to February), TYLCV-viruliferous whiteflies and TYLCV-infected tomato plants were removed or absent from greenhouses. However, S. aquatica plants were observed over a period of 10 months from August to May in such greenhouses, and TYLCV was consistently detected in some of these plants. To investigate the transmission of TYLCV from TYLCV-infected S. aquatica plants to healthy tomato plants by whiteflies, TYLCV-infected S. aquatica plants were transplanted to pots in cages with nonviruliferous whiteflies and healthy tomato plants. After 4 weeks, tomato plants developed typical TYLCV disease symptoms, and TYLCV was detected in both whiteflies and tomato plants. These results show that S. aquatica can act as a winter-hardy reservoir for TYLCV, and suggest that this weed could play an important role in overwintering of TYLCV in tomato greenhouses.