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Sex steroids modulate the distribution of mammalian white adipose tissues. Moreover, WAT remodeling requires adipocyte progenitor cells. Nevertheless, the sex-dependent mechanisms regulating adipocyte progenitors remain undetermined. Here, we uncover Cxcr4 acting in a sexually dimorphic manner to affect a pool of proliferating cells leading to restriction of female fat mass. We find that deletion of Cxcr4 in Pparγ-expressing cells results in female, not male, lipodystrophy, which cannot be restored by high-fat diet consumption. Additionally, Cxcr4 deletion is associated with a loss of a pool of proliferating adipocyte progenitors. Cxcr4 loss is accompanied by the upregulation of estrogen receptor alpha in adipose-derived PPARγ-labelled cells related to estradiol hypersensitivity and stalled adipogenesis. Estrogen removal or administration of antiestrogens restores WAT accumulation and dynamics of adipose-derived cells in Cxcr4-deficient mice. These findings implicate Cxcr4 as a female adipogenic rheostat, which may inform strategies to target female adiposity., (© 2024. The Author(s).)

Sympathetic innervation of brown adipose tissue (BAT) controls mammalian adaptative thermogenesis. However, the cellular and molecular underpinnings contributing to BAT innervation remain poorly defined. Here, we show that smooth muscle cells (SMCs) support BAT growth, lipid utilization, and thermogenic plasticity. Moreover, we find that BAT SMCs express and control the bioavailability of Cxcl12. SMC deletion of Cxcl12 fosters brown adipocyte lipid accumulation, reduces energy expenditure, and increases susceptibility to diet-induced metabolic dysfunction. Mechanistically, we find that Cxcl12 stimulates CD301 + macrophage recruitment and supports sympathetic neuronal maintenance. Administering recombinant Cxcl12 to obese mice or leptin-deficient (Ob/Ob) mice is sufficient to boost macrophage presence and drive sympathetic innervation to restore BAT morphology and thermogenic responses. Altogether, our data reveal an SMC chemokine-dependent pathway linking immunological infiltration and sympathetic innervation as a rheostat for BAT maintenance and thermogenesis., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Perivascular adipocyte progenitor cells (APCs) can generate cold temperature-induced thermogenic beige adipocytes within white adipose tissue (WAT), an effect that could counteract excess fat mass and metabolic pathologies. Yet, the ability to generate beige adipocytes declines with age, creating a key challenge for their therapeutic potential. Here we show that ageing beige APCs overexpress platelet derived growth factor receptor beta (Pdgfrβ) to prevent beige adipogenesis. We show that genetically deleting Pdgfrβ, in adult male mice, restores beige adipocyte generation whereas activating Pdgfrβ in juvenile mice blocks beige fat formation. Mechanistically, we find that Stat1 phosphorylation mediates Pdgfrβ beige APC signaling to suppress IL-33 induction, which dampens immunological genes such as IL-13 and IL-5. Moreover, pharmacologically targeting Pdgfrβ signaling restores beige adipocyte development by rejuvenating the immunological niche. Thus, targeting Pdgfrβ signaling could be a strategy to restore WAT immune cell function to stimulate beige fat in adult mammals., (© 2023. The Author(s).)

Obesity and its' associated metabolic diseases such as type 2 diabetes and cardiometabolic disorders are significant health problems confronting many countries. A major driver for developing obesity and metabolic dysfunction is the uncontrolled expansion of white adipose tissue (WAT). Specifically, the pathophysiological expansion of visceral WAT is often associated with metabolic dysfunction due to changes in adipokine secretion profiles, reduced vascularization, increased fibrosis, and enrichment of pro-inflammatory immune cells. A critical determinate of body fat distribution and WAT health is the sex steroid estrogen. The bioavailability of estrogen appears to favor metabolically healthy subcutaneous fat over visceral fat growth while protecting against changes in metabolic dysfunction. Our review will focus on the role of estrogen on body fat partitioning, WAT homeostasis, adipogenesis, adipocyte progenitor cell (APC) function, and thermogenesis to control WAT health and systemic metabolism., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Steiner and Berry.)

Lutein is incorporated into foods as a natural yellow pigment and nutraceutical. The introduction of lutein into many foods and beverages, however, is problematic because of its strong hydrophobicity and poor chemical stability. In this research, lutein-loaded nanoemulsions were prepared to overcome this problem. Casein-dextran Maillard conjugates or physical complexes were utilized as emulsifiers, while either medium chain triglycerides (MCT) or grape seed oil (GSO) were used as carrier oils. The impact of resveratrol addition on nanoemulsion stability was also examined. The influence of storage temperature, pH, and CaCl 2 concentration on the chemical and physical stability of the nanoemulsions was measured. The casein-dextran conjugates were highly effective at improving the physical resistance of the nanoemulsions to environmental stresses, but had a detrimental effect on their color stability. Conversely, nanoemulsions prepared from casein-dextran physical complexes were unstable around the protein's isoelectric point (pH 4.6), as well as upon addition of CaCl 2 . Incorporation of resveratrol and GSO into the nanoemulsions decreased lutein degradation and color fading at all temperatures. This study shows that casein-dextran conjugates are highly effective at improving the physical stability of lutein-loaded nanoemulsions, while resveratrol and GSO are effective at improving their chemical stability. PRACTICAL APPLICATION: Lutein can be used by the food industry to create "clean label" and functional food products. The major challenges in incorporating lutein in foods are its poor chemical stability and its high hydrophobicity, which makes it difficult to incorporate. Emulsion-based delivery systems assembled from natural ingredients may address these challenges. In this study, the impact of Maillard conjugates fabricated from caseinate and dextran, as well as resveratrol addition, on the formation and stability of lutein-enriched nanoemulsions was determined. The information obtained from this study will help the formulation of more effective functional foods and beverage products., (© 2019 Institute of Food Technologists®.)

Despite the completion of the Treponema pallidum genome project, only minor genetic differences have been found between the subspecies that cause venereal syphilis (ssp. pallidum) and the nonvenereal diseases yaws (ssp. pertenue) and bejel (ssp. endemicum). In this paper, we describe sequence variation in the arp gene which allows straightforward differentiation of ssp. pallidum from the nonvenereal subspecies. We also present evidence that this region is subject to positive selection in ssp. pallidum, consistent with pressure from the immune system. Finally, the presence of multiple, but distinct, repeat motifs in both ssp. pallidum and Treponema paraluiscuniculi (the pathogen responsible for rabbit syphilis) suggests that a diverse repertoire of repeat motifs is associated with sexual transmission. This study suggests that variations in the number and sequence of repeat motifs in the arp gene have clinical, epidemiological, and evolutionary significance.

Background: Since the first recorded epidemic of syphilis in 1495, controversy has surrounded the origins of the bacterium Treponema pallidum subsp. pallidum and its relationship to the pathogens responsible for the other treponemal diseases: yaws, endemic syphilis, and pinta. Some researchers have argued that the syphilis-causing bacterium, or its progenitor, was brought from the New World to Europe by Christopher Columbus and his men, while others maintain that the treponematoses, including syphilis, have a much longer history on the European continent., Methodology/principal Findings: We applied phylogenetics to this problem, using data from 21 genetic regions examined in 26 geographically disparate strains of pathogenic Treponema. Of all the strains examined, the venereal syphilis-causing strains originated most recently and were more closely related to yaws-causing strains from South America than to other non-venereal strains. Old World yaws-causing strains occupied a basal position on the tree, indicating that they arose first in human history, and a simian strain of T. pallidum was found to be indistinguishable from them., Conclusions/significance: Our results lend support to the Columbian theory of syphilis's origin while suggesting that the non-sexually transmitted subspecies arose earlier in the Old World. This study represents the first attempt to address the problem of the origin of syphilis using molecular genetics, as well as the first source of information regarding the genetic make-up of non-venereal strains from the Western hemisphere.

The structural gene for the catalase of Neisseria gonorrhoeae was cloned into a Kat- strain of that organism by using a recombinant vector derived from one of the beta-lactamase-specifying plasmids found in that organism. The kat gene was then successfully subcloned into both pUC8 and pGB2, transformed into Escherichia coli, and shown to complement the E. coli katE mutants UM2 and UMRl. The gene was subsequently mutagenized and returned to the gonococcus to generate a Kat- strain that was phenotypically identical to the strain originally used to clone the gene. The sequence of the gene and the derived amino acid sequence showed that the gonococcal kat gene closely resembles the hktE gene of Haemophilus influenzae. The sequence of the promoter region of the gonococcal kat gene is unusual and may explain the extremely high, loosely regulated expression of the gene.

The lack of a method for demonstrating the presence of Treponema pallidum by growth necessitates the use of alternative methods. Traditionally, these methods are divided into direct detection methods (animal inoculation, dark-field microscopy, etc.) and serologic tests for the presence of patient antibody against T. pallidum. Serologic methods are further divided into two classes. One class, the nontreponemal tests, detects antibodies to lipoidal antigens present in either the host or T. pallidum; examples are the Venereal Disease Research Laboratory and rapid plasma reagin and tests. Reactivity in these tests generally indicates host tissue damage that may not be specific for syphilis. Because these tests are easy and inexpensive to perform, they are commonly used for screening, and with proper clinical signs they are suggestive of syphilis. The other class of test, the treponemal tests, uses specific treponemal antigens. Confirmation of infection requires a reactive treponemal test. Examples of the treponemal tests are the microhemagglutination assay for antibodies to T. pallidum and the fluorescent treponemal antibody absorption test. These tests are more expensive and complicated to perform than the nontreponemal tests. On the horizon are a number of direct antigen, enzyme-linked immunosorbent assay, and PCR techniques. Several of these techniques have shown promise in clinical trials for the diagnosis of congenital syphilis and neurosyphilis that are presently difficult to diagnose.

We obtained a catalase-deficient (Kat-) strain of Neisseria gonorrhoeae isolated from a patient who had been unsuccessfully treated with penicillin. Quantitative enzyme assays and electrophoresis of cell extracts on native polyacrylamide gels subsequently stained for catalase and peroxidase activities failed to detect both enzymes. The strain exhibited no growth anomalies or unusual requirements when grown under ordinary laboratory conditions. However, the Kat- strain proved extremely sensitive to exogenous hydrogen peroxide, and analysis of the bacterial DNA after such exposure showed extensive single-strand breakage in both chromosomal and plasmid DNAs. Partial characterization of the gonococcal catalase from a Kat+ laboratory strain revealed that the enzyme had the physical and chemical properties of both catalase and peroxidase.

The protective immunity conferred by T-cell subsets against infection with Treponema pallidum subsp. pertenue was studied. We demonstrated that hamster T cells can be separated into two subsets by monoclonal antibody (MAb) GK 1.5 (anti-L3T4) and MAb 38. Eighty-five percent of hamster thymocytes were L3T4+ and 87% were 38+ cells; 84% were dual positive for MAbs anti-L3T4 and 38. In the peripheral lymph nodes, however, the L3T4+ and 38+ T cells were mutually exclusive according to two-color immunofluorescence analysis. The two T-cell subsets were found to be functionally distinct according to their secretion of interleukin 2 (IL-2) when stimulated with concanavalin A. The L3T4+ cells secreted IL-2 and had characteristics of T helper cells, while the 38+ cells did not secrete IL-2 and appeared to be T cytotoxic-suppressor cells. Transfer of 4 x 10(6) helper or cytotoxic-suppressor T lymphocytes from T. pallidum subsp. pertenue-immune hamsters protected irradiated naive hamsters against challenge with this subspecies. IL-2 production could still be detected in the irradiated recipients 12 days after irradiation of naive recipients, although at a low level. This suggests that the remaining lymph node cells could support the survival and expansion of the infused cytotoxic-suppressor T cells. No accumulation of macrophages was observed in regional lymph nodes of immune T-cell recipients within 10 days of infection. Instead, there was an influx of polymorphonuclear neutrophils in all animals injected with T. pallidum subsp. pertenue. This report demonstrates that hamster T cells can be separated into two phenotypically and functionally distinct subsets and that both T-cell subsets confer protection against challenge with T. pallidum subsp. pertenue.

The role of cell-mediated immunity against infection with Treponema pallidum subsp. pertenue in humans or experimental animals is unclear. Hamsters injected subcutaneously in the hind paws with 4 x 10(6) unfractionated lymph node cells or enriched lymph node T cells (immunoglobulin negative, Ia negative) from T. pallidum subsp. pertenue-immune hamsters were resistant to challenge with T. pallidum subsp. pertenue. The popliteal lymph nodes of hamsters that received immune cells weighed less and had significantly fewer treponemes than did lymph nodes from hamsters infused with cells from nonimmune donors. Furthermore, recipients of immune T cells failed to develop antitreponemal antibodies 21 days after challenge. Enriched T cells were obtained by flow cytometric separation by using monoclonal anti-Ia antibody 14-4-4s, which identified hamster B cells. Flow cytometric analysis by two-color immunofluorescent staining with anti-hamster-immunoglobulin and monoclonal anti-Ia antibody 14-4-4s confirmed that monoclonal anti-Ia antibody 14-4-4s recognized B cells. In addition, lymph node cells obtained after treatment with anti-Ia monoclonal antibody 14-4-4s and complement were 97% T cells, as determined by monoclonal antibody 20, a hamster T-cell marker. These results demonstrated that highly enriched T cells (immunoglobulin negative, Ia negative) from T. pallidum subsp. pertenue-immune hamsters conferred partial protection on hamsters against infection with T. pallidum subsp. pertenue.

Treponema pallidum partially inhibited the synthesis of DNA, RNA, and protein by rabbit cells in vitro. The inhibition of DNA synthesis was proportional to treponemal concentration and persisted during the period of exposure to T. pallidum. The toxic effect was not dependent on treponemal metabolism or on whole treponemes, since heat- and penicillin-killed treponemes and a cell-free sonicate of treponemes had similar toxicities. The toxic factor(s) was also detected in extracts of syphilitic rabbit testes but not in extracts of normal rabbit testes or testes inflamed by chemical means. The T. pallidum-derived toxic material had a molecular weight greater than 20,000 as determined by dialysis. Protein and DNA synthesis were most rapidly inhibited; RNA synthesis continued at normal rates for up to 2 h after exposure to treponemes. Protein synthesis or a necessary precursor of protein synthesis appeared to be the primary target of the T. pallidum toxin(s).

Treponema pallidum strain Nichols adheres readily to rabbit epithelial cells (SF1Ep) in tissue culture. We examined a variety of sugars for their ability to inhibit attachment. Mannose, galactose, and N-acetylgalactosamine showed minor but reproducible inhibition of attachment at high concentrations, whereas sialic acid was highly inhibitory even at low concentrations. Whole-cell lysates of SF1Ep cells contained a large number of glycoproteins, which might be related to the sialic acid-inhibitable attachment. When the cells and extracellular matrix were fractionated, only a few proteins were found in the matrix fraction. They included a 220-kilodalton (kDa) protein, shown by immunoblotting to be fibronectin, and an approximately 90-kDa protein (both were isolated on SDS-PAGE gels). When nitrocellulose replicas of these SDS-PAGE gels were exposed to 125I-labeled T. pallidum, adherence was mainly to the 90-kDa protein.

A crude enzyme preparation from a nadA mutant of Escherichia coli was used to catalyze the conversion of [14C]aspartic acid into a precursor of quinolinic acid, a key intermediate in the biosynthesis of nicotinamide adenine dinucleotide.

The effect of hydrogen peroxide on Treponema pallidum was investigated. The in vitro loss of virulence (as measured by rabbit inoculation) of T. pallidum was accelerated by as low as 100 microM hydrogen peroxide in the complex maintenance medium used. Higher doses led to rapidly accelerated death with 500 microM hydrogen peroxide causing sterilization of the medium within 3 to 4 h. Since hydrogen peroxide is known to cause single-stranded breaks in DNA, the effect of hydrogen peroxide on the treponemal genome was examined. Extensive breakage was caused by 100 microM hydrogen peroxide as determined on alkaline sucrose gradients. A limit was reached at 250 microM and above. Single-stranded breaks could be demonstrated as early as 5-10 min after exposure to hydrogen peroxide when the treponemes were exposed to 250 microM hydrogen peroxide; accelerated death was evident by 2 h past exposure demonstrating that DNA breakage was preceding death. Treponemal death caused by penicillin did not result in DNA breakage. The repair-proficient bacterium Escherichia coli K-12 was compared with T. pallidum. It required 10-100 times more hydrogen peroxide to cause various levels of breakage. Escherichia coli K-12 rapidly repaired DNA breakage once hydrogen peroxide was removed by addition of catalase. Treponema pallidum, in comparison, showed little or no repair in vitro. Addition of catalase or dithiothreitol to the medium protected against all but a low level of breakage; this may reflect on the ability of catalase and reducing agents to protect T. pallidum against oxygen toxicity in vitro.

Four isolates of an unclassified microaerophilic bacterium resembling Campylobacter species were characterized by growth requirements, microscopic examination, biochemical characteristics, antimicrobial susceptibility tests, and protein profile analysis. The unclassified isolates were differentiated from Campylobacter jejuni, Campylobacter coli, Campylobacter fetus subsp. fetus, Campylobacter laridis, Campylobacter pylori, and an ovine isolate. The bacterium was fusiform shaped with a corrugated surface due to the presence of periplasmic fibers and had multiple bipolar flagella. Biochemically, the bacterium was separated from the Campylobacter controls by its negative catalase reaction, negative nitrate reduction, and no growth in 1% glycine. It was also resistant to ampicillin. Protein profile analysis demonstrated nine major protein bands present in the unclassified isolates that were absent in the Campylobacter controls. The bacterium also differed from the ovine isolate by its negative catalase reaction, rapid urea hydrolysis, and susceptibility to clindamycin, erythromycin, and tetracycline. Our results showed that the unclassified bacterium was distinct from the recognized Campylobacter species.

The effect of various energy sources and metabolic intermediates on the attachment of Treponema pallidum to baby rabbit genital organ (BRGO) cells in culture was examined. Pyruvate and glucose enhanced the motility of T. pallidum in vitro. Pyruvate increased significantly the attachment of treponemes to BRGO cells when compared with the other substrates but all substrates tested stimulated DNA synthesis by cultured BRGO cells. Thus, the effect of pyruvate on attachment may be due to an effect on the treponemes. Prior exposure of the BRGO cells to the glucose analogue 2-deoxyglucose greatly inhibited the attachment of T. pallidum whereas three other analogues had no effect. The inhibitory effect of 2-deoxyglucose was partially reversed by the presence of pyruvate in the attachment assay. These results suggest that energy metabolism of both T. pallidum and host cells may be required for the initial interaction of T. pallidum with its host in vivo.

Experimental studies have indicated that macrophages are involved in the pathogenesis of syphilis. Whether macrophages alone or with immune serum are ultimately responsible for killing of treponemes is disputed. We have demonstrated that BCG-vaccinated hamsters administered normal serum contained fewer treponemes in the inguinal and popliteal lymph nodes than did the nonvaccinated controls. When BCG-vaccinated hamsters were injected with syphilitic immune serum and challenged with Treponema pallidum ssp. endemicum, treponemicidal activity was enhanced. Treponemicidal activity was also detected in BCG-vaccinated hamsters challenged with treponemes treated in vitro with immune serum and its immunoglobulin fractions, especially IgG2. The immune IgG2 fraction had more treponemicidal activity than did the immune IgG1 fraction and the unfractionated immune serum. Our observations indicate an important synergistic role for macrophages and immune serum, especially IgG2, for elimination of T. pallidum ssp. endemicum from the host.

Treponema pallidum extracted from infected rabbit testes under anaerobic conditions survived longer in vitro than those extracted under aerobic conditions. Anaerobically extracted treponemes were incubated anaerobically for 0, 12, 24, 36, or 48 hours and then exposed to microaerophilic conditions (3% oxygen) for further incubation. Treponemes transferred to microaerophilic conditions after 36 or 48 hours' anaerobic incubation maintained significantly greater viability compared with those kept under constant microaerophilic conditions, although there was no difference after 12 or 24 hours. T pallidum incubated under constant anaerobic conditions, however, usually maintained greater viability than those kept under constant microaerophilic conditions. These results suggest that T pallidum is sensitive to oxygen toxicity both during initial extraction from orchitic rabbit testes and subsequent incubation in vitro. In the latter case, it can be partially protected by a period of anaerobic incubation in vitro, before exposure to microaerophilic conditions.

The role of complement in humoral-mediated resistance to frambesial infection (yaws) needs to be defined. The level of serum C3 was reduced shortly after infection of hamsters with Treponema pallidum subspecies pertenue. Five weeks after frambesial infection, the serum C3 level began to increase and by week 7 no difference was detected between infected and uninfected hamsters. When C3 was depleted in hamsters by injection of 20 units of cobra venom factor (CoVF), two alterations in host resistance to frambesial infection occurred. Depletion of C3 abrogated the ability of immune serum to confer complete protection on normal hamsters against infection with the yaws spirochete. In all hamsters receiving immune serum but not CoVF, lesions failed to develop and lymph nodes weighed significantly less (P less than or equal to 0.1) than those of controls. Furthermore, no treponemes were detected in the lymph nodes of passively immunized animals. Second, depletion of C3 increased the susceptibility of hamsters to frambesial infection. The onset and progression of frambesial lesions were enhanced as compared with frambesial-infected hamsters not treated with CoVF. Finally, CoVF treatment did not reduce the ability of frambesia-immune hamsters cured of disease with penicillin to resist reinfection. These results demonstrate that complement influences the pathogenesis of yaws.

Passive transfer of frambesial immune serum is capable of conferring complete protection on hamsters against challenge with Treponema pallidum ssp. pertenue. Treponemicidal activity in the pooled immune serum is relatively high. Immune serum and its immunoglobulin fractions, especially IgG2, also killed T. pallidum ssp. pertenue in vitro. Treponemicidal activity was present only when immune serum was administered to hamsters within a short time (three days) of frambesial challenge. By contrast, administration of pooled immune serum to hamsters infected for more than one week failed to reduce the number and size of lesions and the weight and number of treponemes in the lymph nodes. These results suggest that hamsters can develop the humoral components necessary to protect them against frambesial challenge, but these components are unable to destroy treponemes at the primary foci of infection.

The role of the macrophage in destruction of virulent treponemes is disputed. A major obstacle has been the inability to demonstrate quantitative phagocytosis of treponemes by macrophages. Treponema pallidum pertenue was attached to polycarbonate filters for assessment of treponemal phagocytosis by macrophages. The disappearance of treponemes due to phagocytosis was measured by enumeration with immunofluorescence. Resident and lipopolysaccharide-activated macrophages were found to phagocytize treponemes equally well. The phagocytosis of killed treponemes by macrophages was enhanced by opsonization with immune serum. Macrophages successfully phagocytized Staphylococcus aureus organisms when they were incubated on filters under identical conditions. Treatment of macrophages with cytochalasin B, a known inhibitor of phagocytosis, prevented the disappearance of treponemes and phagocytosis of S. aureus. In addition, fluorescent treponemal debris was observed only inside macrophages cultured with treponemes. These results demonstrate that macrophages can phagocytize pathogenic treponemes on polycarbonate filters.