A bacterial protein has homology with human chorionic gonadotropin (hCG)

Human Chorionic Gonadotropin and Related Peptides: Candidate Anti-Inflammatory Therapy in Early Stages of Sepsis

Sepsis continues to be a major cause of morbidity, mortality, and post-recovery disability in patients with a wide range of non-infectious and infectious inflammatory disorders, including COVID-19. The clinical onset of sepsis is often marked by the explosive release into the extracellular fluids of a multiplicity of host-derived cytokines and other pro-inflammatory hormone-like messengers from endogenous sources ("cytokine storm"). In patients with sepsis, therapies to counter the pro-inflammatory torrent, even when administered early, typically fall short. The major focus of our proposed essay is to promote pre-clinical studies with hCG (human chorionic gonadotropin) as a potential anti-inflammatory therapy for sepsis.

Messenger ribonucleic acid for the gonadal luteinizing hormone/human chorionic gonadotropin receptor is not present in human endometrium

OBJECTIVE

To determine whether messenger RNA for the gonadal LH/hCG receptor is present in human endometrium with the use of reverse-transcriptase polymerase chain reaction.

DESIGN

In vitro experiment.

SETTING

Academic medical center.

PATIENT(S)

Premenopausal women who were not receiving hormonally active medications and who were undergoing hysterectomy for uterine leiomyomas, menorrhagia, pelvic pain, or uterine prolapse.

INTERVENTION(S)

Tissue from hysterectomy specimens was processed for RNA and treated with deoxyribonuclease where appropriate, and RNA was reverse-transcribed to complementary DNA.

MAIN OUTCOME MEASURE(S)

An appropriately sized band after reverse-transcriptase polymerase chain reaction, followed by sequencing to confirm the results.

RESULT(S)

A primer pair that spanned the extracellular domain was unable to amplify receptor complementary DNA from human endometrial tissue. For a primer pair that spanned transmembrane regions 2-6 of the receptor and was contained wholly in exon 11, a 552-base pair fragment was amplified successfully in 19 of 25 human endometrial samples.

CONCLUSION(S)

The traditional gonadal LH/hCG receptor does not appear to be present in human endometrial tissue. The presence of a portion of the transmembrane part of the molecule suggests that human endometrium may express a truncated or variant form of the receptor.

Microbiological and clinical aspects of infection associated with Stenotrophomonas maltophilia

The gram-negative bacterium Stenotrophomonas maltophilia is increasingly recognized as an important cause of nosocomial infection. Infection occurs principally, but not exclusively, in debilitated and immunosuppressed individuals. Management of S. maltophilia-associated infection is problematic because many strains of the bacterium manifest resistance to multiple antibiotics. These difficulties are compounded by methodological problems in in vitro susceptibility testing for which there are, as yet, no formal guidelines. Despite its acknowledged importance as a nosocomial pathogen, little is known of the epidemiology of S. maltophilia, and although it is considered an environmental bacterium, its sources and reservoirs are often not readily apparent. Molecular typing systems may contribute to our knowledge of the epidemiology of S. maltophilia infection, thus allowing the development of strategies to interrupt the transmission of the bacterium in the hospital setting. Even less is known of pathogenic mechanisms and putative virulence factors involved in the natural history of S. maltophilia infection and this, coupled with difficulties in distinguishing colonization from true infection, has fostered the view that the bacterium is essentially nonpathogenic. This article aims to review the current taxonomic status of S. maltophilia, and it discusses the laboratory identification of the bacterium. The epidemiology of the organism is considered with particular reference to nosocomial outbreaks, several of which have been investigated by molecular typing techniques. Risk factors for acquisition of the bacterium are also reviewed, and the ever-expanding spectrum of clinical syndromes associated with S. maltophilia is surveyed. Antimicrobial resistance mechanisms, pitfalls in in vitro susceptibility testing, and therapy of S. maltophilia infections are also discussed.

The role of carboxy-terminal portion of beta subunit of human chorionic gonadotropin in human immunodeficiency virus infection

Human chorionic gonadotropin (hCG) and the beta subunit of this dimer glycoprotein hormone (beta hCG) have been reported by us to inhibit HIV replication. In order to identify the active site responsible for the antiviral activity, twelve overlapping peptides spanning across beta hCG were examined for their effect against HIV-caused cell death. Although the NH2-terminus of beta hCG appeared to contribute to activity, the core region was biologically inert. The most potent activity was observed with the fragment representing the carboxy-terminus of beta hCG. The dose response curve to serial dilutions of the peptide, containing amino acid residues 106-145, had a bell-shaped appearance - characteristic of hCG and beta hCG. The peak of activity corresponded to 100 ng/ml - the dose at which two thirds of virus-exposed MT-4 T lymphocytes survived. None of the tested peptides were toxic to MT-4. While the mechanism of action remains unclear, the results suggest that the COOH-terminal portion, unique to beta hCG, confers anti-HIV activity.

Complete sequence of the gene encoding a chorionic gonadotropin-like protein from Xanthomonas maltophilia

Our laboratory has previously reported that: (i) Xanthomonas maltophilia (Xm) produces a protein which has immunological resemblance to the beta-subunit of human chorionic gonadotropin (hCG) and (ii) possesses a high-affinity receptor which binds holo hCG, and the endogenous ligand, Xm chorionic gonadotropin (xCG), but does not bind human luteinizing hormone (hLH). We have also previously published a 492-bp partial nucleotide sequence of the gene (xcg) coding for xCG. We report herein the entire xcg sequence of 1362 bp, which codes for a 48-kDa protein. This sequence confirmed the 492-bp sequence, as well as two partial amino acid (aa) sequences which we have previously reported. The sequence has a region which is homologous to aa 56-139 of the beta-subunit of hCG, and a second region homologous to the C-terminal tail of hCG. This is the first report of a prokaryotic gene homologous to the hCG beta-subunit-encoding gene.